My dog’s nose seems to be all clogged up and hard and he is not well at all

Canine distemper

Following recent outbreaks of Distemper (Hondesiekte in Afrikaans) in Kwa Zulu Natal and Gauteng, it is important to have an understanding of this disease which is fatal in half of all cases of dogs that contract the disease.

What causes Distemper?

Distemper is a virus disease caused by the Canine Distemper Virus or CDV. This virus is a morbillivirus in the Paramyxoviridae family which is a virus group that affects humans, vertebrates and birds. This specific virus is not transmissible to humans but specifically targets dogs hence the name “Canine” Distemper Virus. The virus is closely related to measles virus in humans, and also to rinderpest virus in cattle, which at the beginning of the previous century almost killed the entire cattle population of Southern Africa. It’s a nasty virus.

What are the symptoms of Distemper?

The virus attacks mainly the respiratory system (from the nose right into the lungs), the gastro-intestinal system (from the mouth, through the stomach into the small and large intestines) and the central nervous system (mainly the brain). This means that the symptoms associated with the disease will be related to problems with these three main systems. In acute to subacute infections the dog will usually develop a fever within a day or two from being infected. The dog will go off its food and become weak and lethargic

Respiratory system symptoms may include a clogged up nose typically with mucous or slime that becomes hard, and hardening of the nose itself. This is a very telling symptom of Distemper but is by no means the only, or most typical, presentation of the disease. A dog with distemper may have a perfectly normal nose and still have the disease. Many times there will also be a discharge in the corners of the eyes. Other respiratory symptoms include coughing, sneezing and difficult breathing if the virus attacks the lungs.

If the gastrointestinal systems is affected you may see vomiting and/or diarrhoea.

If the central nervous system is involved you may have muscle tremors, a dog which seems disorientated and walks around as if they are drunk (ataxia), hind limbs which are dragged or seem lazy (paresis), a dog which cannot get up or falls down when they do get up (paralysis), and even seizures. Other symptoms which are not immediately visible and which only the vet may be able to pick up are lesions on the retina at the back of the eye, or an inflammation in the front of the eye called anterior uveitis. Hardening of the footpads  (hyperkeratosis) was previously quite common because of the strains of virus involved, but seem to be less common these days.

How is Distemper diagnosed?

There are several blood tests which can be done by the vet, but it is a difficult disease to diagnose because unlike a disease like biliary or tick fever in dogs where you can see the parasite in the blood with a bloodsmear, in Distemper, as with all other virus diseases, you cannot see the virus as it is simply too small. The trouble with the blood tests are that they are often not conclusive. The reason for this is that some of the tests, test if the dog is building up antibodies (“soldier”) against the virus. However a dog that may previously have been vaccinated may show antibodies and not have the disease. Sometimes the dog may die acutely before the body was able to produce neutralising antibodies, so in that case the test may be negative, yet the dog still had the disease.

Another type of blood test where the white and red blood cells are counted and where the white cells are less than usual, called lymphopenia,  may give an indication that the dog has a virus disease but it will not tell which virus the dog has.

If the dog has central nervous system symptoms, the fluid around the brain and spine called Cerebro Spinal Fluid (CSF) may contain antibodies but once again it may not be 100% diagnostic. There are other tests which can be run on the CSF (cell or protein content) which may be indicative, but does not conclusively confirm that the dog has Distemper.

There are a number of other diseases which can present with similar symptoms which the vet will have to rule out. On the respiratory side there is Kennel Cough or other upper respiratory tract infections. On the intestinal side there is Parvovirus and Coronavirus, parasitism like worms or Giardia, bacterial infections, toxin ingestion or inflammatory bowel disease. On the neurological side there is granulomatous meningoencephalitis, protozoal encephalitis (toxoplasmosis, neosporosis, babesia), cryptococcus or other infections (meningitis, Ehrlichiosis), pug dog encephalitis and lead or other poisoning.

Clearly Distemper is not a simple disease to diagnose and the vet will often have to rely on the age of the dog, its history, the results of the clinical tests and the appearance of the clinical symptoms, to make a diagnosis of Distemper.

How is Distemper transferred?

The virus is typically inhaled through the air from other sick dogs and also from physical contact with infected animals. The virus can survive for a period of time in the environment and if a dog which carries the virus sniffed around or spent time in a certain environment, it will leave tiny, tiny droplets (aerosol) which contain the virus in that area, which can then infect other dogs. A dog which is infected will inhale or ingest the virus and the virus will quickly spread through the mucous membranes to the local lymphnodes (these are like the remote “army bases” of the body which has to protect the body against invasions) where it will multiply and within one week the whole body will be infected.

How is Distemper treated?

Vets have over the years tried antiviral drugs of which there are very few anyway,  and none have been effective. As with almost all virus diseases one has to support the body in its own fight against the virus because it is only once the body has been successful to produce antibodies (the “soldier cells” which kill the “terrorist” or virus), that the dog will be able to overcome the disease. Often, when the body is attacked by viruses and the immune system is fighting hard to overcome the infection, bacteria will cause a secondary infection and make the whole situation worse. Therefore antibiotics are often administered even though it will do nothing against the virus, but at least it will help the body fight off opportunistic bacterial infections and help the body to overcome the disease. Other treatment depends largely on which systems are affected and to what extent. The vet will typically give symptomatic treatment, for example if the dog has seizures, the vet may administer a drug to help contain the seizures and make them less violent. Certain drugs should not be given and it is important to consult with the vet in case you think your dog may suffer from Distemper.

Can Distemper spread to humans or cats?

In the past it was suspected that the Canine Distemper Virus can cause Multiple Sclerosis in humans. However this has been proven NOT to be the case and as far as we know the disease cannot spread from dogs to humans. Similarly, as far as we know, this disease cannot be transferred to domestic cats.

What is the prognosis should my dog contract Distemper?

Unfortunately the prognosis is not good and the mortality rate is 50%. It will be very difficult for the vet to tell whether your dog will fall in the 50% that will survive or the 50% that will not make it. The vet will have to assess the extent and severity of the clinical symptoms and the progression of the disease and based on that, will advise you whether treatment has any chance of success or not. An important thing to remember is that even though the disease may not appear to be very far advanced when you first present your dog to the vet, and there seems to be early good response to treatment, like the clogging of the nose and the discharge in the eyes clearing up, the dog may still develop fatal central nervous system signs later on. It is important to understand that the vet has no control over which way the disease may go and will do his or her best with your animal’s best interest at heart, when recommending treatment or not.

Can Distemper be prevented?

A resounding yes! Vaccination has been hugely effective in almost eradicating this disease and all dogs should be vaccinated, preferably yearly at the same time as their annual health exam. Your vet will give you more specific advice related to the area you live in and the risk factors involved and should the vet think that annual vaccination is not necessary, the vet will advise you accordingly.

Puppies and old dogs are more commonly affected and all puppies should go through an initial vaccination program from 6 weeks onwards to provide protection. Puppies born from mothers who were vaccinated and had antibodies will get this protection from the initial milk or colostrum from the mother in the first few days after birth. The protection provided through the mother’s milk will start waning after six weeks and this is why vets normally start vaccinating at this time, and repeating the vaccination three or four times with booster vaccinations with monthly intervals and then yearly thereafter.

What do I do if I suspect my dog to have Distemper?

Get them to the vet as soon as you can. Home remedies or treatment is unlikely to give your dog a fighting chance. Proper supportive and secondary infection treatment remains the mainstay of treatment.

Most importantly, have your dog vaccinated. Prevention is always better than cure!

© 2019 The Code Company Vetwebsites

My older German Shepherd Dog seems to be getting weak in its hindquarters

This article outlines a genetic disorder that mainly German Shepherd dogs are prone to. There are other breeds affected by this condition too like Chesapeake Bay Retrievers, Corgis, Boxers, Wirehaired Fox Terriers and Rhodesian Ridgebacks, however, the disease is mostly seen in German Shepherds.

If one breaks down the name of the disease it describes what happens with the disease. Degeneration refers to a breaking down or deterioration of something. That “something” in this case is myelin which is the insulating sheath around neurons in the spinal cord. Neurons are the “electrical wires” of the nervous system and one can compare myelin to the insulating plastic around the wires, almost like one would find with an electrical cord. Whenever a term is followed by “pathy” it refers to a disease or disorder in a certain part of the body. In this case the spinal cord.

Degenerative Myelopathy is a debilitating condition for which there is no cure but only the potential to slow down the progress.

The occurs typically in older German Shepherd Dogs. The average age at which clinical signs start and progress is from 8 to 12 years of age. This is not a condition with rapid onset but instead is slowly progressive with clinical signs worsening with time. Degenerative myelopathy starts out as a very slowly progressive hind limb weakness and loss of function of the back legs called paresis. It is commonly confused with hip pain because the symptoms can mimic hip dysplasia, another debilitating condition with a high incidence in German Shepherds.

The condition is the result of a demyelination (loss of protective cover) and nerve degeneration of the spinal cord in the region of the mid to hind back. This degeneration is something referred to as an ascending lesion meaning that it starts at the tail end of the spinal cord and works its way towards the head. The underlying cause of the disease is thought to be a genetic mutation (change) of the SOD1 gene. This gene is responsible for the protection of cells against certain particles that damage the DNA of cells. The name given to the damaging particles are free radicles. Under normal circumstances the SOD1 gene produces a free radicle scavenger i.e. it helps to clean up the system and prevents damage to the sheath surrounding the nerves.

The way in which the defect is inherited determines whether a particular dog is at a high risk of getting the disease or if they are a carrier of the genetic mutation without showing clinical signs. An individual dog has to carry 2 copies of the mutation in the genes of the cells of their bodies for it to cause the disease. There is no sex predilection, so male or female dogs may be affected equally. What is interesting about the disease is that even if an individual dog has both copies of the mutated gene and they are at very high risk of developing the disease, there are still other factors that influence whether or not they do contract the disease and to what extent they do.  

As mentioned previously this a slowly progressive condition that has a time frame of about 3 years before severe debilitating disease sets in. The clinical signs noticed in dogs include the following:

After 6 to 12 months of contracting the disease, you will notice weakness and partial loss of function of the back legs. Your dog may seem weak and wobbly on the back legs and they may struggle to get up or be slower to get up that what they used to be. When they run, their back legs may sway abnormally.

After 9 to 18 months on contracting the disease, the back legs start to get even weaker and collapse under the dog from time to time. If one assesses the reflexes in the back legs like the patella reflex, you will find that they are abnormal and weakened.

After 12 to 24 months of contracting the disease, the front legs start to become affected and you may notice that your dog starts losing their normal co-ordination and function. By this point, the hind legs are very weak and your dog may struggle to stand and use their legs correctly. Unfortunately, the nerve degeneration also influences bladder and bowel control and they will start to urinate and defecate involuntarily. This is known as urine and faecal incontinence.

After 24 to 36 month of contracting the disease, and if the dog was able to come this far and still cope with the disease, they develop tetraplegia or quadriplegia which is a paralysis that causes partial or total loss of use of all their limbs and body. The loss is usually sensory and motor, which means that both sensation and control are lost, or put a different way, the dog does not know where its legs are and even if they did, they do not have the ability to correct it. Clearly a very unhappy situation.

The way in which this condition is diagnosed by the vet is through a number of tests as well as the typical clinical signs and also the breed of your dog. These, together with the thorough history of the condition, should provide the veterinarian with some very important clues to what is going on with your dog. The important diseases or differential diagnoses to rule out are spinal disc disease (like a slipped disc) and conditions affecting the lower part of the spine where the hips meet the spine, like hip dysplasia or joint disease. The biggest difference with degenerative myelopathy and the other conditions is that degenerative myelopathy is painless because it is the loss of sensation and function which underlies this disease. Special tests such as MRI’s may be done to visualise the damage within the spinal cord and there is also a DNA test available to check if your dog has the genetic mutation discussed earlier.

Unfortunately, there is no specific treatment available. Certain supplements can be used in an attempt to slow down the condition, such as vitamin E and aminocaproic acid. The vitamin E is an essential vitamin which helps various systems in the body to protect it from these damaging free radicles. The aminocaproic acid is an agent used to prevent the breakdown of clots in the bloodstream. The reasoning behind using this is that it is believed that the spinal cord may be indirectly attacked by the body’s own immune system. Antibodies in the bloodstream attach to the foreign material within the bloodstream forming complexes and these stimulate a response from the immune system. These complexes are usually removed by the liver and spleen. Sometimes they can stick to the walls of blood vessels, damage the walls and stimulate the formation of blood clots. The breakdown of these clots are associated with inflammation and this may result in damage to the surrounding tissues, so-called collateral damage. If this happens in the sensitive tissues of the spinal cord, the damage is devastating because the nervous tissue is not able to regenerate and repair itself. The thinking behind using aminocaproic acid is to inhibit clot breakdown in these delicate tissues.

Lastly and most importantly, the most effective treatment for this condition and the only one proven to actually slow down the progress is the use of physiotherapy and hydrotherapy. Another key factor is, the sooner the dog is diagnosed and treatment started, the better the progress of the disease can be slowed, and the more time the vet can give you with your dog. Unfortunately, the sad truth is that eventually, the disease will lead to complete paralysis and eventually, in most cases, euthanasia.

Genetic disorders like degenerative myelopathy can only be prevented by not breeding with animals where there is a family history of the disease. Make sure if you buy a puppy, that you get references on a breeder before you buy.

©2018 Vetwebsites The Code Company (Pty) Ltd

I found a lump on my animal’s skin. Is it cancer?

Finding a lump or a bump in your pet which you have never noticed before, can cause serious worry for pet owners. This article will highlight what to watch out for when to take your pet to the vet and the process veterinarians follow when approaching any lump found on a pet.

Firstly, it is always important to remember that you can never tell how serious a mass on your pet is by simply feeling it and judging by its size. Dynamite can often come in small packages and some of the most aggressive skin cancers may present as a simple small raised area on the skin. Generally, lumps on a cat tend to be more dangerous and they are not something to be ignored. All growths have to start small but may grow very rapidly. Lumps come in all shapes and sizes and for that reason, it is always best to get any lump on the skin or underneath the skin checked by the veterinarian as soon as you discover it. This will provide peace of mind to you as an owner if it is simply a dermal cyst or a small wart-like growth, both of which will not cause any major health issues for your pet. Alternatively, if it is something more aggressive and dangerous, it is always better to start treatment as soon as possible. If it is determined to be a bad type of growth (malignant), the sooner it is diagnosed the better the prognosis for both removing it surgically or starting any other form of treatment.

When you bring your animal to the vet there are a few questions the vet will ask that are essential to determine when and if the lump will be removed.

1. When did you notice the mass and has it grown since noticing it? Masses that grow quickly will invariably need to be removed regardless of the cells that make up the mass. The reason for this is that it will only continue to enlarge and may eventually lead to impaired function of the area of the body it is growing from or may cause discomfort and become more difficult to remove later on.

2. Is the lump bothering your pet, are they scratching, biting or licking it? Any lump that bothers your pet is causing them discomfort and this is the last thing we want. It also predisposes them to infections in the area as the licking and scratching will traumatise the mass with a subsequent breakdown in the skin’s protective barrier.

3. Has your pet ever had any other masses that were of concern? Certain growths on the skin, mast cell tumours for example, do have a tendency to regrow or spread to other areas. Once the vet has gained sufficient information from the pet owner, a more in-depth assessment of the lump will commence.

Usually, a visit to the vet will start with the vet obtaining a history from you regarding the pet’s health which will then be followed by a physical clinical examination of your pet. The vet will then examine the appearance of the lump and determine if there are any other lumps present on or under the skin. The appearance of a mass may give a clue as to what the mass might be. A small round firm lump may simply be a cyst. Small superficial wart-like growths on the skin surface are often benign and only need to be monitored. If they are injured or bleed, they may have to be removed. A dermal cyst may eventually rupture discharging its contents and resolve on its own.  A dermal cyst may however re-occur and the only way to get rid of it for good will be to surgically remove it. Once the vet has had a look at the appearance of the mass they will then most likely perform a fine needle aspirate. This procedure involves placing a needle into the mass with a syringe attached to the needle. The plunger of the syringe is drawn back and with some luck, a small sample of the cells making up the lump will be drawn into the needle. Once this small sample of cells is obtained it is sprayed onto a glass slide for fixing, staining and observation under a microscope. It is rare for the vet to make a definitive diagnosis of what type of growth and how aggressive it is with a single or even multiple fine needle aspirates. However, the small sample of cells obtained may give the vet an idea of the type of cells making up the growth and how urgently it needs to be removed, if at all. There are three types of lumps which can generally be identified more accurately based on these small samples which are, lipomas (which is a benign fatty growth not considered to be a cancer), mast cell tumours (which is a bad type of cancer) and a melanomas (which is a really bad type of cancer). The exclusion of these three types of growths already helps somewhat in determining a prognosis. If it does turn out to be a mast cell tumour or a melanoma, the grade and the subtype of these masses will still need to be determined so just identifying it is not enough. Generally, the vet can determine the type of cells present, for example, a round cell tumour, which may be present in a number of specific growths, but the final diagnosis of which type of round cell tumour and the stage cancer can only be definitively identified by histopathology. Histopathology is where either the full growth or a portion of it is removed surgically and sent to a specialist pathologist who then examines the tissue sample sent with high-resolution microscopy and makes a definitive diagnosis. Round cell tumours generally have to be removed surgically as they grow quickly and are locally invasive into surrounding tissues. Other cell types that may be seen are spindle cells, epithelial cells, glandular cells, fat cells etc. If a cyst is aspirated then one will only see cyst material or debris and no obvious cells. If these lumps are subsequently gently squeezed, the contents of the cysts will be extruded.

Any lump or bump which is cancerous should be surgically removed and sent for histopathology for definitive diagnosis and grading. This is also important to ensure that the surgical margins are clear which means that all cancer cells were removed and none of the growth was left behind. This is particularly important for very aggressive tumours such as mast cell tumours, as they invade the surrounding tissue easily and to a large extent. To remove these tumours, a margin of 3 cm around the entire mass, and 2 tissue planes deep have to be removed by the surgeon. The resulting wound to be closed after surgical removal of a tumour can be very extensive with a high risk of post-operative complications. It is with these masses, as you could imagine, that the smaller the growth, the better it is to catch it early.

Instances where you would not remove lumps and bumps include

  1. cases of wart-like growths on the skin called adenoma’s. Unless they have been traumatised by the animal scratching, biting or licking them or where they have grown too large, it does not have to be removed.
  2. dermal cysts come and go and unless the owner wants them permanently removed, they do not need to be surgically removed.
  3. the very common growth known as a lipoma, which is a soft lump underneath the skin which is usually not firmly attached to the underlying tissues and do not seem to bother the animal at all. A lipoma is, in essence, a tumour of fatty tissue, but it is benign and only grows locally.

Lipomas are generally benign, well-encapsulated growths which do not invade surrounding tissues and they can sometimes grow very large, sometimes up to the size of a rugby ball, without posing any systemic risk to the animal. The problem is that they become a physical problem which interferes with the animal’s sitting or lying down or movement. Smaller lipomas can initially be monitored and not removed, but should they continue to grow, it is advisable to get them surgically removed before they start to interfere with your pets ability to move and live a normal comfortable life.

In conclusion, when you find a lump or bump on your pet, rather take them to the vet to have it checked out so that it can be diagnosed and treated. If advised by the veterinarian to remove the growth, it is always better to do it sooner rather than later. Lastly, remember that no growth is too small to be ignored.

© 2018 Vetwebsites – The Code Company Trading (Pty) Ltd

Can my kitten make me sick?

There are many diseases that can be transmitted from animals to humans. These diseases are called zoonotic diseases. Although the list below is by no means comprehensive, some of the more common diseases that we can get from our household pets are:

  • Ringworm, which is a fungal infection of the skin
  • Hook worm, roundworm and tapeworm infection
  • Toxoplasmosis
  • Cat scratch disease
  • Scabies, a mite that causes severe itchiness and skin lesions

In this article we are going to look at cat scratch disease (CSD), the cause of it, the symptoms and how to prevent it. Cat scratch disease, or cat scratch fever, is caused by an organism called Bartonella henselae or formerly called Rochalimaea henselae. It is a small anaerobic (organism which does not need oxygen to survive), gram-negative, non-motile bacterium. Domestic cats are the natural hosts for this organism and the animal from which humans can contract the disease (also known as the vector). If a cat harbors this bacterium, the cat very rarely shows any signs of the disease which is described as asymptomatic. It is therefore impossible to tell if a cat is infected with this organism without further testing. Fleas are the organism responsible for transmission of the disease between cats and therefore flea control is one of the best ways to prevent this disease. The infection rate is much higher in a population of cats that are flea ridden and can be as high as 61%. As a cat scratches and bites at fleas, the organism gets stuck between their teeth and under their nails. Kittens younger than 12 months are 15 times more likely to carry the infection than adult cats.

Cats transmit the disease to humans when they bite or scratch a person, causing a break in the skin. There is no evidence to suggest that fleas can transmit the disease directly to humans through a flea bite. Bacteria are also found on the coat of infected cats and can be transmitted to a person with open wounds on their skin by just stroking or holding an infected cat. Bacteria enter the wound of the affected human and causes local inflammation with swelling and redness of the area. A vesicle or an erythematous papule (a small blister almost like a pimple) may form at the site of initial infection during the progression of the infection. Soon after the initial bite or scratch, people develop signs of fever, headaches, decreased appetite, nausea, muscle pain, chills and joint pain. There is a swelling of the lymph glands closest to the area where the initial bite occurred. This is also known as a regional lymphadenopathy. The lymph glands become enlarged and painful and the nodes glands most commonly affected are in the armpit, the groin and the junction between the neck and jaw.

Cat scratch fever is a self-limiting disease in people with a healthy immune system. The disease resolves without specific treatment within 6 to 12 weeks. In children younger than 5 years as well as immune compromised people, complications can occur. Impaired immune systems can be the result of HIV infection or cancer patients receiving chemotherapy. In these cases treatment is necessary and this entails putting the patient on a course of antibiotic tablets which has to be prescribed by a medical doctor. Complications that can occur in patients with weakened immune systems are the following:

  • Meningoencephalitis (infection of the membrane around the brain)
  • Encephalopathy (infection of the brain itself)
  • Seizures
  • Endocarditis (infection of the heart)
  • Granulomatous conjunctivitis (infection in the eye)
  • Optic neuritis (damage to the main nerve running from the brain to the eye)

The best way to avoid this disease is to avoid situations where you can be bitten by a cat. Kittens are often playful and rough play frequently results in scratches or even bites. When bitten or scratched, it is important to wash the wound thoroughly under running water and cleaning it with a disinfectant. Never let cats lick open wounds on your skin. Since the disease is transmitted to cats by fleas, good tick and flea control is very important in your cat. It is important to take note that you should treat all your animals (dogs, cats and any other animals you may have) for fleas, even if you find just one flea on only one animal in your household. It is often difficult to see fleas on your cat because by grooming themselves they actually often catch and shallow fleas during the process. It is advised that people with weakened immune systems adopt cats that are older than one year of age, since kittens are the most likely carriers of the disease. Keeping your cat’s nails trimmed can also help prevent infection.

If you experience any of the above named symptoms after being bitten or scratched by your cat, it is strongly advised that you see your doctor.

© 2018 Vetwebsites – The Code Company Trading (Pty.) Ltd.

My dog is scooting on its backside and I think it has worms

Many veterinarians are presented by concerned pet owners about the animal’s scooting or dragging their backsides along the ground by holding the back legs up in the air and pulling themselves forward by the front legs whilst remaining in a seated position. The owner often thinks that the animal may have worms and is trying to get the worms out their backside by dragging it along the ground. Although this is quite possible to be the case, especially in the case of tapeworm infestation, it is unlikely to be the cause. The most common cause for this behaviour is uncomfortable anal glands.

Anal sac disease is the most common disease entity of the anal region in dogs. The anal sacs, commonly referred to as anal glands, are located on either side of the anus at 4 ’o clock and 8 ’o clock and are present in cats and dogs. The sacs are reservoirs for a secretion produced by glands within the wall of the sacs. The sacs have little ducts, which open just within the anus and connect the sacs to the outside. The secretion is released when the animal passes stool or when they are scared or nervous. It is often yellowy brown to grey and foul smelling to us, but it is an important scent marker in dogs. These are the same glands that are responsible for the foul smell secreted by skunks when they are threatened.

The sacs can become inflamed, infected and blocked and occasionally tumours can form within them. Small breed dogs appear predisposed to anal sac disease, although medium and large breed dogs can be affected too.

Why do the anal sacs cause a problem in dogs?

Anal sac disease is relatively common in dogs. The anal glands become blocked or impacted due to the ducts becoming inflamed. The anal gland secretion thickens and the sacs become full and swollen. The glands can be described as being inspissated. It can become painful for the animal to pass a stool or defaecate. If the sac is not emptied, the contents are a perfect medium for bacterial growth and for an abscess to form. The abscess will appear as a red, painful and swollen area on one or both sides of the anus. Sometimes, the abscess can burst. If left untreated, the abscess can spread infection to the anus and rectum.

What clinical signs can you expect?

Clinical signs are associated with pain when the patient sits or passes a stool. Commonly, anal gland disease will present with the dog licking the area around the anus, scooting (rubbing the anus along the ground) and the animal may experience pain when passing stool. Sometimes, an abscess may form that then bursts. Blood or pus may be seen around the anus.

What treatment is there for anal sac disease?

On clinical examination, the veterinarian will perform a digital exam of the rectum. This is very useful as the sacs can be nicely felt or palpated. The vet will try and express the glands. If there is an abscess or a tumour, this is not always possible. Normal anal sac fluid is thin and the sacs are easily expressed. The anal sac fluid can become very thick and difficult to express. If the sacs are just inflamed, they may need to be expressed manually over a few days. In the case of an abscess, antibiotics and anti-inflammatories may be required. Sometimes, antibiotics may be instilled into the sac for a few days. In some very severe cases and in the case of anal sac tumours the sac and duct will need to be removed surgically by a veterinary surgeon.

Can anal sac disease become a chronic problem?

Some dogs can have recurrent anal sac impactions or abscess. Overweight dogs tend to be overrepresented, as the sacs do not always empty completely. With each impaction or abscess, the sacs can become scarred and so making emptying even more difficult. The anal sacs may need to be manually expressed more regularly and in chronic cases surgically removing the gland may be an option. Adding fibre to the diet to bulk up the faeces may assist in emptying the sacs as the stool passes through the anus. Speak to your vet about your pet’s nutrition to ensure you are using the best diet possible to counter this disease.

Although the anal sac secretion is an important territorial scent marker, it is not important in the domestic dog, so removing the sac should not cause any adverse effects if done correctly.

Even though anal sac disease is the most common reason dogs scoot, one has to always ensure that it is not in actual fact worms that cause this behaviour. It is sound practice to deworm your dogs and cats at least three to four times a year with a good broad spectrum dewormer you can get from the vet.

© 2018 Vetwebsites – The Code Company Trading (Pty.) Ltd.

Is your pet safe?

Fatal Diseases that can easily be prevented

There are some fairly common fatal diseases in animals which can and should be prevented wherever possible. This article looks at how these diseases present, what they lead to and most importantly how they could be prevented. Today we have more information about our animals and the diseases they may suffer from than ever before. With this knowledge comes the means of preventing these conditions that years ago would have meant certain death to our beloved pets. The most important means of disease prevention readily available to us is vaccination. A simple annual health check and vaccinations can help ensure your pet lives a long and healthy life. Other important means of prevention includes regular deworming as well as tick and flea treatment.

Here are just a few of the conditions our animals can be prevented from getting:

Rabies (affects dogs and cats)

Rabies is a viral disease affecting the brain and spinal cord of all mammals, including cats, dogs and importantly humans as well. This is a fatal condition for which there is no cure once infection has taken hold. It is important to remember that the idea we have of rabies and how an infected animal may present and act may only be half the story.  A rabies infected animal (domestic and wild animals alike) can present in one of two forms – the commonly known aggressive form, and the lesser known ‘dumb’ form. The aggressive form will be the animal that appears very aggressive, tries to bite and often is salivating at the mouth. The ‘dumb’ form is unusual and not well known because animals appear tame, calm, docile and even slightly sedated. These animals may have excessive salivation but not always. This animal appears calm until approached and then will just as easily bite you. Both forms have the same end result for the infected animal or human – severe inflammation and damage to the nervous system resulting in death. Rabies is transmitted through contact with an infected animal’s saliva, most often through a bite but other contact may also result in infection. In the event contact is made with any body fluids of an infected animal there is a risk for infection.

Treatment: None

Prevention: Vaccination

Distemper (this is a disease that only affects dogs)

Distemper is a serious viral disease that is highly contagious and for which there is no known treatment. This virus is transmitted through direct or indirect contact with infected animals, and may even be transmitted via the air. This virus first attacks the tonsils and lymphatic system (the body’s drainage and filter system) and then spreads to the gastrointestinal, respiratory, urogenital (kidneys and bladder system) and nervous systems. Initially the dog is feverish and un-well and there may be vomiting and diarrhea. Later there is progression to involve other internal organs and systems including the brain which may lead to seizures, behavioural changes, paralysis etc. Animals may also develop hard thickened foot pads. Most animals diagnosed with distemper need to be euthanised.

Treatment: None

Prevention: Vaccination

Parvoviral infection (CatFlu) in dogs

Parvovirus infection is mainly a problem in young unvaccinated puppies but can also affect dogs of any age if they have not been vaccinated. Initially is was thought that dogs contracted this disease from cats but this is not true and cats are not affected by this disease at all. The small and very tough virus that causes this disease attacks and destroys the intestines, resulting in vomiting, lack of appetite, and a severe watery bloody diarrhea. Even with intensive treatment puppies often succumb to dehydration with loss of nutrients and electrolytes essential for life. Treatment is costly, intensive and can still result in the death of your pup. Parvo is a preventable disease, with adequate vaccination of mom, ensuring she passes on essential protective antibodies to her pups. Once the pups are born they have to undergo a complete puppy vaccination program from 6 weeks of age onwards to ensure they remain protected at all times.

Treatment: Intensive therapy with intravenous fluids by having the dog on a drip, antibiotics (which cannot kill the virus but protect against bacteria infecting the animal whilst the virus is causing damage, drugs to prevent vomiting, electrolyte supplementation, nasogastric tube feeding and monitoring of electrolytes, proteins and blood counts

Prevention: Vaccination

Infectious Canine Hepatitis (affects dogs)

Infectious canine hepatitis (ICH) is a worldwide, contagious disease of dogs with clinical signs varying from a mild fever and red mucous membranes to severe depression, white blood cells deficiency, and bleeding tendencies. It is also carried by a number of wild canids (dog like animals) such as foxes, wolves and others. These carriers don’t often show clinical signs of the disease but are important in its spread to our dogs. As suggested by the name this virus attacks the liver primarily and results in varying degrees of damage which leads to clinical disease. The disease in a dog can vary from a mild fever from which they can potentially recover with supportive treatment, to death (especially in younger animals). The main route of infection occurs through ingestion (either directly/indirectly) of urine, feces, or saliva of infected dogs. Dogs that have survived infection shed the virus in their urine for more than 6 months. 

Treatment: Supportive and symptomatic treatment which includes fluid therapy (placing them on a drip), antibiotics to prevent secondary invasion of the body by bacteria and controlling the bleeding tendencies that result from the damaged liver which amongst other things produce the clotting factors which prevent an animal from bleeding spontaneously.

Prevention: In recent years there has been a reduction in the incidence of this disease as a direct result of active vaccination programs. Vaccination is the only sure way of preventing the disease and with the many carriers of the disease it is important our animals are continuously protected.

Feline Panleukopenia (affects cats)

Feline panleukopenia is a highly contagious, often fatal, viral disease of cats that is seen worldwide with kittens being the most severely affected. The virus is very resistant and can persist in the environment for a long time. Cats are infected by exposure to the stools or other secretions of infected animals or contaminated objects. The virus infects and destroys actively dividing cells in bone marrow, lymphoid tissues, intestinal cells, and in young animals the nervous system. It may also lead to abortions in pregnant cats. Animals infected with this virus may die acutely, or may present with fever, weakness and later vomiting and diarrhea. On examination they often have painful abdomens. They can also appear anemic (pale). Eventually affected animals become systemically ill and septic, eventually resulting in their death. In young kittens affected with the virus they can show a variety of nervous signs such as ataxia and tremors with increasing severity depending on the age of the kitten when infected and the extent of damage to the nervous tissue.

Treatment: Supportive and symptomatic treatment with fluid therapy, antibiotics (to prevent secondary bacterial infection), checking electrolytes and other body systems on an ongoing basis until the animal is better. Some animals may even require blood transfusions with severely anemia. The outcome of treatment cannot be guaranteed.

Prevention: Vaccination.

If you are in any doubt as to when your animals should be vaccinated or what diseases they should be vaccinated against, please phone the veterinarian to book an appointment and to make sure you keep your animals safe from potentially fatal diseases.

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Feline Leukaemia Virus (FeLV) infection in cats

Introduction

Feline leukaemia (FELV) is a disease of cats caused by a virus called a retrovirus. It is called a retrovirus because of the method it uses to replicate inside the cat. It is the same type of virus as the human immunodeficiency virus and although there are a lot of disease similarities, several studies have shown that the disease is not transmissible to humans. FeLV is one of the most dangerous diseases that affect cats and is a major cause of death in cats. Fortunately the prevalence of the disease has decreased in recent years due to the use of vaccines against the disease and the ability of vets to diagnose the disease early and accurately.

How do cats contract Feline Leukaemia?

The disease is more prevalent in cats between one and six years of age and is more often seen in males than females. The virus is present in high quantities in the saliva of an infected cat, but also in smaller quantities in the stool and urine. The virus gets transmitted through cats biting each other as well as through grooming each other. In a few circumstances it can also spread between cats by sharing food and water dishes. It can also be transmitted from the mother to a foetus inside the womb, as well as through milk from the queen to the kitten once the kittens are born. If one considers the way the virus spreads it should be clear that multi-cat households will be more affected than single cat households. Cats that roam outdoors are also more exposed in terms of getting into contact with other infected cats.  If your cat is infected with Feline Leukaemia at an age younger than 8 months it is most likely that the disease was contracted from the mother. If a cat gets sick with Feline Leukaemia after 8 months of age it is more likely that the infection was contracted from other cats in the household or roaming cats.

What does Feline Leukaemia do?

Not all cats that get infected with the FeLV virus develop severe disease. With initial infection the cat’s immune system may fight the virus and get rid of it completely. In other circumstances the cat’s immune response is not adequate and the virus infects tissues like lymph nodes and the bone marrow. The virus can lie dormant in these cells for years, not causing disease but if the cat is stressed or the immune system challenged, the virus may start replicating and cause full blown and serious disease.

There are four different subgroups of the virus causing different disease processes in the cat’s body. A cat can be infected with one, two or all four of the different types. The different types are called FeLV-A, FeLV-B, FeLV-C and FeLV-T. FeLV-A is found in almost all naturally infected cats and tends to be less severe disease than viruses of the other subgroups. FeLV-B causes cancer in cats and occurs in about 50% of cats with FeLV. FeLV-C affects the bone marrow and red blood cells and can cause severe anaemia or low red blood cell count. FeLV-T causes a severe drop in immunity because it destroys white blood cells called T-lymhpocytes which play an important role in the defence mechanisms of the cat’s body. 

The clinical signs which cats will show depend on what type of subgroup virus it is infected with. The signs seen most often are loss of appetite or anorexia, depression, weight loss, unexplained fever, poor coat, infections in the mouth like gingivitis (or gum infection), eye infections, diarrhoea and enlarged lymphnodes. Typically the virus causes a slow deterioration of the cat’s health over a number of months. Owners will often notice that the cat will be more listless, skip meals more often and show slow weight loss. The cat will have minor ailments more often due to the decreased immune system and will need to be taken to the vet more often. These symptoms will alert the vet to test for this virus.

How is Feline Leukaemia diagnosed?

Fortunately we live in an age where there are much more efficient methods to diagnose FeLV now than in the past. It can be done with a simple test at the vet, called a FELV snap test or Elisa test. All that is required for this test is for the vets to take a small blood sample from the cat and do the test with the results being available within a few minutes. If the results are not clear or definitive or if one needs to know what stage the infection is in, another test can be done at a laboratory for which blood needs to be sent away. This test is called an IFA or immunofluorescence assay test. It is important to realise that other common infections needs to be ruled out first. A full blood count and organ function test will often be done at the same time as  this will provide the vet with information on how the virus has affected the different body systems at the time of making the diagnosis. It will also serve as a reference point for future monitoring of the disease to see how the virus progresses and may serve as a prognostic indicator.

Treatment options for Feline Leukaemia

Sadly there is no cure for full blown Feline Leukaemia. Cats can only be treated symptomatically and made as comfortable for as long as possible. Infected cats will need extra attention and need to be taken to the vet more frequently for regular health checks. Their basic health care like deworming, flea treatment and vaccinations needs to be done regularly. With regular vet visits the vet can pick up any problems early and start treatment as soon as possible. Regular blood tests should be done to determine deterioration as early as possible. It is recommended to visits the vet at least every 6 months if your cat is diagnosed with FeLV infection.

Because the immune system of affected cats is compromised, these cats may often require treatment with antibiotics for secondary bacterial infections. It is important to give antibiotics for at least 7 to 14 days to prevent the build-up of antibiotic resistance. Blood transfusions can be given to anaemic patients and chemotherapy is an option for cats with cancer. It is important to remember that these treatments do not provide a cure, but alleviates the symptoms of the disease to some extent and make life more comfortable for infected cats. Unfortunately 85% of persistently infected cats die within 3 years of being diagnosed.

Infected cats should always be placed on a good quality diet. Never feed a raw diet as this can introduce infections. They should be kept indoors to protect them from any infections but also to prevent the spreading of the disease to other cats. FeLV infected cats should be kept as stress free as possible. They also tend to do better in a single-cat household rather than in a multi-cat household. Never introduce a new cat into the household with an already infected cat, as this may lead to increased stress and fighting and transfer of the disease.

How to prevent healthy cats from getting infected with FeLV?

The most important method to prevent infection is to keep cats indoors and not let them roam. There are also vaccinations available against FeLV. Before having your cat vaccinated, you have to have them tested for FeLV first. When introducing a new cat into the household, always have them tested for FeLV beforehand. When one of the cats in a multicat household is diagnosed with FeLV, have all the cats tested and vaccinate all the unaffected cats. There has been no benefit shown to vaccinate an already infected cat. If at all possible it will always be beneficial to separate an infected cat from other cats.

Feline Leukaemia may be a terrible disease but it is by no means an immediate death sentence when a cat is diagnosed with the disease. With modern advances in veterinary medicine and care, infected cats can live a good quality life for years after they were initially diagnosed.

© 2018 Vetwebsites – The Code Company Trading (Pty.) Ltd.

 

 

Frequently Asked Questions about Rabies

Aggressive Cat with RabiesHow often must I vaccinate my dog?
Puppies should be vaccinated at 3 months old with a booster vaccination required a month later and a booster given within 12 months of original vaccination. Thereafter animals who live in Rabies endemic areas like KwaZulu Natal should be given a rabies vaccination every year and animals living in non-Rabies endemic areas every 3 years by law,  but preferably also yearly, because in places like Johannesburg which is non-Rabies endemic there have been several outbreaks of Rabies in the past few years.

My child was bitten by a mouse (shrew, rat or monkey). Must he or she receive anti-rabies treatment?
If bitten by shrew or rat then contracting rabies is not likely, however, seek medical attention to treat bite wound as they can become infected. If bitten by a monkey, depending on the behaviour of the animal, anti-rabies treatment may be indicated, seek medical attention.

Must I have my cat vaccinated against rabies?
Yes. Rabies vaccination is required by law every 3 years, however preferably should be done annually.

I have been bitten by a dog. The dog is very aggressive and frequently bites people. What must I do?
Treat the wound immediately by flushing the wound for 5 – 10 minutes. Seek medical attention immediately where the doctor will determine whether vaccination and RIG therapy is required. Whereabouts and description of the aggressive dog should be reported to the authorities as a dog has bitten many people and is a risk to the population.  

I was bitten by a rabid dog four days ago and I was given rabies vaccine within a day of the incident but no RIG was administered. What must I do now?
RIG therapy is required. It can be given up to 7 days after the 1st vaccination. A person that has received RIG therapy should be observed afterwards for an hour for any harmful side effects

My farm staff dug up the carcass of a rabies-positive cow that had been buried a day ago. The staff then consumed the meat of this carcass. What must be done now?
Seek medical attention IMMEDIATELY. The farm staff will probably require vaccinations and RIG therapy. Destroy the remaining meat from the rabies positive cow by either burning or burying.

We have been drinking the milk of a rabid cow up to the day she was destroyed. What should be done?
Seek medical attention IMMEDIATELY.  Vaccination and RIG will post probably be indicated. Bury the remaining milk from the rabies positive cow.

What is the earliest age that I may vaccinate my puppy or kitten of rabies?
3 months

Is it safe to give rabies vaccine at the same time as other dog vaccines, e.g. distemper, parvo and hepatitis?
Yes

What side-effects will rabies vaccination have on my animal?
Animals may vomit,  have facial swelling, fever or lethargy. In rare instances, animals may experience anaphylactic shock, paralysis or death. However, the side effects of the rabies vaccine rarely occur and should not prevent you from getting your animals vaccinated regularly.

One of my dogs is positive for rabies. What should I do about my other animals?
It depends on your remaining dogs’ vaccination history. If your dogs have had no vaccinations then they will be humanely destroyed. If they have had rabies vaccinations by a registered veterinarian or authorised official and you have proof of these vaccinations, then the dogs will receive a rabies vaccination booster on day 0 and day 3, the dogs will be placed in quarantine for 6 months, and if there is no change in behaviour, then the dogs can be released from quarantine.

How soon after vaccination are my dogs protected against rabies?
7 – 10 days

Should wild animals which are kept as pets be vaccinated against rabies?
Wild animals should be vaccinated against rabies however the immune response would be unknown as current rabies vaccine is tested for domestic animals.

My cow was positive for rabies. What must I do about this cow’s calf and the other cattle that were in contact with this cow?
Contact your state veterinarian. He/she will decide if humane slaughter or isolation and vaccination is necessary.

My dog and cat were vaccinated during a rabies campaign. However, I do not have any documentary proof that vaccination was done. Should there be contact with rabid animals, what is their vaccination status?
Your dogs’ and cats’ vaccination history is considered unknown and would, therefore, be considered not up to date. Blood can be taken and a rabies titre determined. If greater then 0.5iu/ml then this indicates that the animal has adequate protection against rabies, and should be kept isolated from other animals for 6 months, if there is no change in behaviour then the animal can be released.  If the titre is less then 0.5iu/ml, contact your State Veterinarian to find out the next step as there was the only contact between your pets and a rabid animal and no report of a bite. The next step could be quarantine or humane destruction.  Getting and keeping a formal record of Rabies vaccination is critically important and as it is governed by law it is like driving without a driver’s licence.

Can rabies be transmitted between people?
Yes but only if a rabid human bites another person or receives an organ/blood transfusion from a rabid human.

I was bitten by a mongoose two weeks ago. What should I do?
Seek medical attention immediately even 2 weeks after the bite. Wound treatment, vaccination and RIG therapy can be started.

Can birds contract rabies?
No

What part do bats play in rabies transmission in South Africa?
The risk of rabies transmission is highest in bats that feed on blood. Vampire bats are not found in South Africa. It is unlikely that a bat that usually feeds on fruit, insects or pollen would contract rabies. However, bats are mammals and can, therefore, contract Rabies and an accidental scratch or bite from infected bats could potentially cause rabies in a person.  Rabid animals lose their fear of humans and as unsolicited aggression is a known symptom of Rabies, it should always be considered a possibility if a human is bitten by a bat.

Can clinical rabies in humans be treated?
The treatment for clinical rabies involves sedation, pain management, and the maintenance of fluid and electrolyte balance. There is no cure for clinical rabies in humans and in most cases the disease is fatal. Family members should be informed of the poor prognosis and receive the necessary counselling and support that they need.

© 2018 Vetwebsites – The Code Company Trading (Pty.) Ltd.

Rabies

Rabies, a fatal disease of humans and all other mammals, is caused by a virus which has been associated with animal bites for more than 3 000 years and it is the oldest infectious disease known to medical science. Dogs have long been recognised as the main transmitters of the disease to people. When compared with other formidable human diseases such as Bubonic Plague and Smallpox, and animal diseases such as Rinderpest and Anthrax, Rabies has probably never caused comparably high numbers of deaths in humans and animals. However, the horrendous manner in which Rabies manifests itself in its victims continues to attract the attention of scientists, health and veterinary workers. The true scale of Rabies in South Africa remains clouded by the many thousands of people protected by post-exposure treatment each year after Rabies exposure and the undiagnosed human and animal Rabies cases not reflected in official statistics.

Animal Rabies is endemic throughout South Africa and the disease is currently responsible for the laboratory confirmed deaths of between 10 and 30 people each year. Tragically, with very few exceptions, those who succumbed to the disease over the past decade did not receive the correct post-exposure prophylaxis and died following bites by rabid dogs.

There have been several new and exciting developments in our knowledge of the disease and in measures used to control Rabies in South African animals. The use of monoclonal antibody typing, together with gene sequencing technology, have revealed several different strains of the Rabies virus, some of which appear to show clear host preferences. The entire country was declared Rabies-endemic during 1999 and it is now compulsory for all dogs and cats to be vaccinated at least once every three years.

Shedding of virus in saliva usually occurs simultaneously with, or soon after, the appearance of clinical signs and progressive with death usually within 10 days in animals and five days or less of the onset of Rabies symptoms in humans (J.D Godlonton, personal communication).

Following central nervous system infection, the virus is transported centrifugally along cranial nerves and along motor and sensory pathways as well as the spinal cord. This results in the presence of viral particles in peripheral nerve tracts in many tissues, particularly those of the head. Therefore, a diagnosis of Rabies may sometimes be possible by examination of skin sections, where antigen can be detected within nerve tracts, or corneal smears.

In all mammalian species the host is not infectious for most of the incubation period. Rabies infection is fatal in all species and no species is known to have a carrier state where virus is shed in the absence of clinical signs or imminent clinical signs. Exceptional and rare cases of human survivors have been recorded in a handful of cases where the patients did receive some prophylaxis but had severe residual neurological sequelae. To date only one case of a human survivor has been recorded in a patient who did not have any history of prophylaxis. The reason for the patient’s recovery is still being investigated and disputed.

Animal and human Rabies vaccines consist of inactivated whole-virus antigens on a cell culture or neural tissue substrate and, in the case of more modern cell-culture vaccines, partially purified to remove unnecessary proteins. Generally, veterinary pre-exposure vaccination, while human vaccines, which are considerably more expensive to produce, are used post-exposure. Pre-exposure vaccination may be recommended in people at high risk. There are no records of human Rabies cases that have occurred in people fully vaccinated according to World Health Organisation (WHO) recommendations.

Post-exposure prophylaxis of humans, using vaccine and immunoglobulin according to WHO recommendations, provides rapid and effective protection if administered soon after exposure. The most frequent causes of failure of post-exposure prophylaxis are delays in administering the first failure vaccine dose or immunoglobulin, failure to complete the vaccine course and failure correct wound management. Infiltration of the wound with immunoglobulin does not interfere with stimulation of the immune system by vaccine, which is administered at a site distant from the wound.

Rabies appears to spread fairly well within bat-eared fox populations, yet transmission of infections to other species is relatively rare. The underlying reasons for this are still to be elucidated. Population dynamics (including population turnover) and the distribution of susceptible animals are extremely important factors determining the prevalence of Rabies in other species, and the bat-eard fox is no exception.

The most important maintenance host of mongoose Rabies is the yellow mongoose, Cynictis penicillata, a diurnal animal that lives in colonies of 10 or more individuals. The disease has been endemic in yellow mongoose populations for decades and possibly centuries. Attempts by veterinary authorities to control the disease by depopulation, for example by gassing burrows and trapping, have only had a transient effect. These measures may ultimately have accelerated the spread of the disease by increasing the territories of yellow mongoose colonies with concomitant increase movement. Spreading infection to suricates, which are migratory herpestids living in groups of up to 30 individuals, and ground-squirrel populations are fairly common, because these species often share warrens or live in close proximity to yellow mongoose colonies.

Humans and domestic animals such as sheep, cattle and dogs have been infected and succumbed to mongoose Rabies virus but are regarded as dead-end hosts because spread within these species is rare.

Clinical signs

Apart from behavioural changes, there are no definitive, species specific clinical signs of Rabies. Although certain clinical signs are more frequent than others, even the most experienced diagnostician may make an incorrect diagnosis when presented with an unusual case. Rabies can mimic many other diseases but it always has a neurological component.

Because Rabies affects the central nervous system, it is nearly always associated with behavioural changes that may manifest in many different ways. Classically, Rabies has been described as having a prodromal phase followed by either an excitive furious form, or a paralytic dumb form.

The veterinarian is, however, rarely afforded the opportunity to observe an animal throughout the clinical course of disease and diagnosis is often made after minimal observation, especially in endemic areas where Rabies awareness is heightened.

Dogs:

Change in temperament, attacking and biting anything (often injuring mouth and breaking teeth), exaggerated responses to sound and light, restlessness, nervousness, snapping at imaginary flying insects, disorientation, wandering aimlessly, a fixed stare, drooling saliva, hoarse howling, choking sounds, “bone in throat” syndrome, a febrile reaction, uncoordinated actions and progressive paralysis, dilated pupils, irritability, photophobia, infliction of self-injury, convulsions, and muscle spasms.

Cats:

Generally aggressive, uncoordinated , frothing, muscular tremors, dilated pupils, staring, a threatening posture, abnormal vocalisation, lack of response to owners, unprovoked attacks, biting (sometimes without releasing grip), convulsions, paralysis, coma, hiding away, some cats appear unusually affectionate and purr, or extend and retract their claws.

Cattle:

Several animals may have clinical signs at the same time, a typical hoarse bellow, aggressive particularly on provocation, vicious attacks on inanimate objects, butting other cattle, attacking humans, wind-sucking, “bone in throat” syndrome, separate themselves from rest of herd, anorexia, knuckling of fetlocks especially hind limbs, swaying gait, tail and posterior limb paralysis, jaw and tongue paralysis, profuse salivation, dragging hooves, pseudo-oestrous, hypersexual behaviour, decreased milk production, dilated pupils, fixed stare, grinding teeth, pica, tenesmus with diarrhoea, frequent urination, loss of condition, and emphysema.

Sheep / goats:

Symptoms resemble those of cattle but hypersexual behaviour, sexual excitement, incessant bleating, aggression, aimless running, pawing and paddling, and grinding of teeth are prominent.

Horses:

Febrile reactions, altered behaviour, biting of wound site, aggression, thrashing, paralysis, and inability to swallow.

Pigs:

Hiding in corners of pen, hypersexual behaviour, aggression, biting, and may kill off springs.

Wild animals:

Often lose fear of humans.

Yellow mongooses generally demonstrate tame behaviour, but some are very aggressive.

Jackal are usually aggressive, and lose fear of humans.

Wild cats display similar behaviour or domestic cats. Badgets are usually victim and fierce.

Kudu salivate profusely, may be paralysed, docile, tame, even entering houses. Duiker are sometimes very aggressive.

Diagnosis

Confirmation of a clinical diagnosis of Rabies cannot be made by gross pathology or histology. Specific test must demonstrate the presence of Rabies antigen. Animals displaying signs of neurological disease, and all stray and wild animals suspected of exposing humans to Rabies infection, should be euthanized for examination. The Directorate Veterinary Services may hold suspected cats and dogs in quarantine for observation by a veterinarian for a period of at least 10 days. Animals displaying signs of illness during the period of observation are euthanased for laboratory examination. A vaccination history may be of some assistance during the assessment but greater reliance should be placed on the animal’s clinical picture. Although the inactivated veterinary vaccines used in South Africa are known to be extremely effective for periods exceeding three years following vaccination, there are compelling reasons for avoiding undue reliance on vaccination history alone.

These include:

  • The incorrect vaccine may have been administered
  • The incorrect dosage and route may have been used
  • The vaccine may have been incorrectly handled or stored
  • The animal may have been misidentified
  • Vaccination may have been performed after infection had already occurred
  • The animal may have been immuno-suppressed
  • The animal may have been diseased or in poor condition when vaccinated
  • The animal may have been diseased or in poor condition when vaccinated
  • The animal may have been very young at vaccination and nod boosted at three months.

Prevention of Rabies

Pre-exposure vaccination

A number of recently developed, highly effective, thermo stable, inactivated vaccines are available in South Africa for veterinary use. The duration of immunity conferred varies from one to three years. Most veterinary vaccines are only registered for use in specific species, for example dogs. Although there are no safety limitations to their use, their efficiency in other species, for example mongoose, is not guaranteed. All Rabies vaccines registered for human and animal use must conform to established potency standards. A minimum antigenic potency of 2,5 IU per dose is mandatory.

The vaccines may be used in young pups, but they must be boosted at three months of age and again within the following year. Revaccination must be carried out every three years thereafter. Cattle and sheep may be vaccinated annually or every two to three years, depending on the vaccine manufacturer’s instructions. Some farmers inoculate their herds every year in jackal and dog Rabies endemic areas with these inexpensive vaccines as they consider this practice to be economically sound.

Following an outbreak in domestic livestock, vaccination of animals without visible bite wounds is strongly recommended. In cases where bite wounds are visible, or there is direct evidence that an animal was bitten, the animal should immediately be isolated and destroyed.

Post-exposure prophylaxis

Post-exposure prophylaxis (PEP) of bite-contact unvaccinated carnivores, including dogs and cats, is not recommended in South Africa. Preliminary reports indicate that antibodies in the form of anti-Rabies immunoglobulin (RIG) in combination with vaccine yielded poor results. The use of PEP in animals is not without risk and is not recommended for use in animals in South Africa.

Rabies in Humans

Epidemiology of human Rabies

Rabies is an ongoing scourge exacting an unnecessarily large toll on human life. The World Health Organization estimates about 55 000 human deaths in canine Rabies endemic areas (31 000 in Asian countries and 24 000 in African countries) annually. Rabies virus is transmitted via the saliva of infected animals and has the highest case fatality rate of any known human infection if the disease has manifested. Once the virus has entered the central nervous system of the host, the resulting encephalomyelitis is fatal. Fortunately the availability has prevented many fatalities and almost 10 million people receive post-exposure prophylaxis annually after potential Rabies exposure, mostly following dog bites.

Distribution in South Africa

During the first half of the 20th century most human Rabies cases in South Africa resulted from herpestid, particularly yellow mongoose, bites in the central plateau areas. However, following the introduction of canid virus into Limpopo Province in the late 1940s, and later into KwaZulu-Natal in 1961, dogs became the most important source of human infection. In recent years the last majority of South African human Rabies cases have followed bites from infected dogs in KwaZulu-Natal. An outbreak of Rabies in dogs coincided with a dramatic increase in the number of human cases in the Limpopo Province in 2006.

Most victims have been children under the age of 10 years. Children are particularly vulnerable because of their height, inquisitive nature, interest in animals and inability to protect themselves. Surveillance of human Rabies is poor in many parts of South Africa and it is likely that the situation may be worse than that reflected by official notifications. A careful history taken from a victim’s family has demonstrated a high sensitivity for diagnosing Rabies in other African settings and may prove a useful approach in areas suspected of having Rabies cases that have not been notified.

Canine vaccine delivery targeted to highest risk populations and broad intersectoral collaboration are believed to have contributed to the marked reduction in human Rabies in KwaZulu-Natal during the latter part of the 1990s.

Transmission to humans

Human Rabies cases result from viral introduction through broken skin or mucosa through encounters with rabid animals, particularly bites, but also scratches and nicks. Virus is usually present in the saliva of the affected animal during clinical disease but secretion may be intermittent. Experimental demonstration of virus in salivary glands or saliva several days before risk of transmission during slaughtering, these cases are usually classified as category 2 exposures and require the administration of vaccine, or when physical injuries have been acquired during slaughtering as category 3 exposures.

As all mammals are susceptible to Rabies, any infected mammal could potentially transmit Rabies to humans. However mice, rats, shrews and monkeys have yet to be incriminated as vectors of Rabies in South Africa. Rats and mice, particularly those kept as pets, frequently inflict retaliatory bites on children when cornered and caught. Rabies infection has never been shown to transmit Rabies virus in South Africa, they are however vectors of Rabies related viruses such as Duvenhage virus and Lagos bat virus.

Preventing human Rabies

Rabies is one of the top 10 global infectious causes of mortality and one of the most amenable to available preventative measures. Primary care providers can play a crucial role in preventing Rabies, by providing accurate prevention messages including the avoidance of suspicious animals, immunising people at high risk of Rabies exposure, ensuring optimal wound management, and correctly administering immunoglobulin and Rabies vaccine after suspected exposure to Rabies virus.

Pre-exposure prophylaxis

A recent review found that at current Rabies vaccine prices, routine use of pre-exposure vaccinations is generally not cost-effective. There are, however, particular high-risk situations where pre-exposure vaccination is cost-effective and it would ne negligent not to recommend it. In South Africa the cost of pre-exposure prophylaxis is borne by vaccine recipients or their employers.

Pre-exposure vaccinations involves administration of Rabies vaccine on days 0, 7 and 28 (or day 21). Variation of a few days in the timing of second and third doses does not, however, affect the immune response. Currently, two vaccines are licensed for use in South Africa, the purified chick embryo cell culture vaccine and the purified vero-cell culture vaccine. These vaccines are considered safe and effective when administered according to the guidelines put forward by the World Health Organization.

Practically all human Rabies cases result from introduction of virus through broken skin by the bite of a Rabies infected mammal

Rabies vaccine induces an active immune response that includes the production of neutralising antibodies. The antibody response requires approximately seven to 10 days develop. The duration of persistence of this booster vaccinations. Routine serological measurements of the vaccine recipient’s blood can indicate the presence of levels considered adequate for protection. Virus neutralizing antibody levels of greater than 0.5 IU/ml are considered to be protective by the World Health Organization. A small study confirmed rapid boosting of antibodies up to 19 years after a previous vaccine course.

As it has repeatedly been found that people with intact immune systems experience a satisfactory response to approved vaccines, it is only necessary to demonstrate an adequate serological response in immunocompromised individuals or those working with live virus and those who are blood donors for Rabies vaccines products. Rabies-neutralising antibodies are analysed by a neutralisation test. Two booster vaccinations (day 0 and day 3) should be administered to all vaccinated individuals that has had risk of exposure to rabid animals irrespective of their antibody titres and they should not receive immunoglobulin.

Although a two-dose schedule (days 0 and 28) has also been investigated, results have confirmed the superior long-term immunogenicity of the three-dose approach for pre-exposure prophylaxis.

High-risk occupational groups

People with increased occupational risk of exposure to infection, such as veterinary staff, wildlife handlers, laboratory personnel working with Rabies virus or animal welfare staff, should receive pre-exposure prophylaxis. This should preferably be by administration of three doses vaccine into the deltoid muscle on days 0, 7 and 28 (or day 21).

Because the virus may be present in the saliva of patients with Rabies, there is a potential risk of health worker exposure.

Human to human transmission has however never been reported under these circumstances. Infection control measures to protect health workers caring for patients with Rabies should be instituted to protect against bites and exposure to infected saliva: gowns, gloves and goggles. Post-exposure prophylaxis with Rabies vaccine may be considered in selected cases if there has been significant exposure i.e. bite from an infected patient. Surveillance staff responsible for bleeding dogs as a plague indicator species in Rabies endemic areas are another occupational group that clearly merit pre-exposure vaccination.

Children in Rabies-endemic areas

Routine vaccination could be beneficial for children in countries where Rabies is enzootic. As children are particularly vulnerable and experience a higher frequency of bites to the head and neck as a result of their inclination of Rabies vaccine in the Childhood Expanded Programme on Immunisation in Rabies Vero cell vaccine with diphtheria, tetanus, whole-cell pertussis and inactivated poliomyelitis vaccine and administering these vaccines at two, three and four months, or alternatively at two and four months, resulted in all infants developing protective antibody concentrations against all five diseases with no serious adverse events. A larger trial, also in Vietnamese infants, comparing intramuscular and intradermal vaccine administration demonstrated that both routes provided acceptable antibody titres (0.5 IU/ml).

Unfortunately current vaccine costs prohibit routine childhood vaccination against Rabies. There is, however, a clear mandate for children to be formally educated on Rabies transmission, the disease and prevention, particularly as educational interventions have proven effective in reducing the number of dog bites in children.

Rabies and travellers

Rabies in an important disease for the burgeoning travelling community. In the United States, for example, 37% of people dying from Rabies are infected in foreign countries. Canine Rabies is endemic in some of the developing countries of Asia, Africa and South America. This poses a risk to travellers, particularly in the backpacking or adventure category. Unfortunately discussion on reducing Rabies risk is one of the topics often neglected by travel medicine advisors during pre-travel consultations. Travelling to these areas must be educated concerning their risk of Rabies exposure and informed regarding local reservoir species so that they can avoid contact with potentially rabid animals. They should also receive instruction on correct wound cleaning, the importance of correct post-exposure prophylaxis with vaccine and immunoglobulin, and their availability at the traveller’s destination.

Travellers with potential occupational exposure should certainly receive appropriate three-dose pre-exposure vaccination and this should also be considered for all long-term expatriate residents in high-risk areas, particularly those living in close proximity to the local population and their dogs.

Debate continues over the merit of administering routine pre-exposure vaccination for other categories of international travellers to Rabies-endemic countries. The rate of animal bite exposure in international travellers has been estimated to be two to four people per thousand and in the majority of these cases there is some concern about Rabies infection. However, where correct post-exposure prophylaxis is available, this is effective in preventing Rabies and pre-exposure vaccination is of less importance. Although local reactions, such as pain, swelling and itching, occur in most vaccine recipients and mild systemic reactions, such as headaches, nausea, muscle aches, abdominal pain and dizziness are reported by 5 to 40% of people vaccinated, serious adverse events are rare. The major constraint against routine administration remains the cost of pre-exposure vaccination. The cost, for example, of preventing Rabies in United States tourists to Thailand by routine pre-exposure vaccination was estimated at between US$ to 50 million per Rabies death prevented.

The death of a human from Rabies should be viewed as a health failure

On the other hand, areas where stray dogs are a problem are often the specific areas where canine Rabies is endemic, and efficacious vaccines and immunoglobulin are not available.

Fraudulent vaccines, nerve-tissue derived vaccines and equine immunoglobulin commonly associated with severe adverse reactions may be used in these countries. In certain areas tourists are frequently exposed to dogs, for example a survey of European travellers in Thailand found that in less than a three week period 1.3% of tourists experienced dog bites and 8,9% dog licks. Advantages of pre-exposure Rabies vaccination include requiring only two boosters, on day 0 and 3, if there is an exposure, no need for immunoglobulin, and diminished concern about inadequate therapy and vaccine failure.

Advice and vaccination should be adapted to the individual needs and exposure risks of traveller, taking into account the area visited, local Rabies epidemiology, mode of travel, and underlying medical conditions and medication. Travellers who are immunocompromised by disease or selected medications are a group deserving particular attention as immune response to vaccine for which Rabies pre-exposed vaccination is indicted. When this is not possible, immunocompromised individuals who are their antibody titres checked post-vaccination.

Management of humans exposed to Rabies

The death of a person from Rabies should be viewed as a health system failure. This contention is supported by e review of failure post-exposure prophylaxis in Thailand, which found that delays, failure to provide post-exposure prophylaxis or deviations from the recommended regimen contributed directly to the deaths of young children.

Findings from studies in South Africa and Thailand have highlighted deficiencies in health workers’ knowledge on managing suspected Rabies exposures.

It is therefore recommended that a confidential enquiry routinely be conducted to establish avoidable factors which may have contributed to the death.

Although no controlled human trial of Rabies post-exposure prophylaxis utilising wound treatment, immunoglobulin and vaccination has been conducted and such a study would be unethical, extensive global experience provides convincing support for this approach.

There is a critical need for veterinary and health workers to be adequately trained on assessing Rabies risk and appropriate response. It is also imperative that health and veterinary workers involved in managing human cases with potential exposure to Rabies virus remain in close communication so that patient management can be modified by data about the source animal. The health worker is obligated to make contact with the responsible state veterinarian. Laboratory-confirmed human Rabies and exposure to proven rabid animals is notifiable in South Africa.

Assessing risk after exposure

Important factors that assist decisions on prophylaxis, include details of the nature of the contact and the implicated animal’s behaviour. It is imperative that prophylaxis be instituted as soon as possible after exposure to Rabies in the animal. Ideally post-exposure prophylaxis should be administered to all bite victims, but availability and costs of the biological is a problem. The approach adopted in South Africa on providing prophylaxis to those individuals at high risk of Rabies infection.

To reduce the risk of Rabies, it is important that thorough cleaning of the bite wound is initiated as soon as possible

Judgement on whether to initiate post-exposure prophylaxis is assisted by an estimation of risk based on the following criteria, with a high risk of exposure necessitating vaccination:

  • Type of contact. Bats may be involved in transmitting Rabies-related viruses, i.e. Duvenhage and Lagos Bat virus, and any encounters should be considered. Small rodents e.g. Mice rats commonly found in an around dwellings are not typically associated with Rabies. To date in South Africa there has only been one transmission of Rabies associated with a bite from a baboon.
  • Incidence of Rabies in the animal’s district of origin
  • Animal’s behaviour (any abnormal behaviour could indicate Rabies)
  • Species of animal involved
  • Vaccination status of animal (if not vaccinated, then higher risk)*
  • Results of Rabies laboratory testing (a negative result from an approved Rabies veterinary laboratory indicates a lower risk)
  • When the biting animal cannot be traced, caught or identified, or the brain is not available for laboratory examination, it should be assumed that the animal was rabid.
  • An animal vaccinated before 3 months of age with no booster may not be protected from Rabies.

There is no blood test for the human victim that can confirm or exclude transmission of Rabies virus from an infected animal.

Any decision to provide post-exposure prophylaxis is made on the risks of the exposure to the human victim. Post-exposure prophylaxis should not be delayed pending the results of Rabies laboratory tests in the animal.

The most important criteria are the non-availability for assessment of the biting animal in an endemic area, abnormal behaviour in the animal and type of contact. If in doubt, it is preferable to vaccine.

In the case of AIDS patients (or otherwise immunosuppressed patients) it is particularly important to focus on thorough wound care when a Rabies virus exposure is suspected. The immune response to Rabies vaccine has been shown to be decreased in HIV infected persons. It is therefore advised that human Rabies immunoglobulin be administered together with vaccine not only for category 3, but also for all category 2 exposures for these patients. No other administration is currently advised.

Management of the wound

To reduce the risk of Rabies, it is important that thorough cleaning of the bite wound in initiated as soon as possible. The bite wound should ne copiously flushed immediately for 5 to 10 minutes with water or soap and water, while irrigation of deep puncture wound, for example following a feline bite, should be performed using a syringe. If antiseptic is available, for example a 1 in 20 dilution of 5% chlorhexidine in water, then this may be added to the water. Bleeding should be encouraged and wound suturing should preferably be avoided or delayed. Applying an iodine-based disinfectant or 70% alcohol to the wound after flushing is also indicated, as these chemicals inactivate Rabies virus.

To lessen the risk of bacterial infection, antibiotic therapy should be considered. As most infections following mammalian bites comprise multiple pathogens, with mixed aerobic and aerobic species, it is essential that therapy should be selected appropriately. In addition to the usual aerobic and anaerobic Pasteurella multocida, which is isolated in 20 to 30% of dog-bite wounds, and is particularly associated with cat bites, and a cause serious infection with severe complications, and Capnocytophaga canimorsus, which can induce sepsis following apparently minor bites particularly in immunocompromised individuals particularly those without a functioning spleen.

Antibiotic therapy is modified in line with laboratory culture susceptibility results when a patient requires hospitalisation as a result of severe local or systemic sepsis. Additional indications for hospitalisations include penetrating injuries of tendons, joints or the central nervous system, severe bites to hands or head and neck, patients requiring reconstructive plastic surgery with certain high-risk medical conditions, for example diabetes, asplenia, and peripheral vascular disease.

The administration of anti Rabies immunoglobulin complements Rabies vaccination in situations where viral transmission may have occurred

To prevent tetanus, a booster dose of tetanus toxoid (TT) absorbed vaccine (0.5 ml intramuscular) should be given at the time of wound treatment in individuals who have completed a primary course of tetanus vaccination. Most adult tetanus cases occur in people who do not have a vaccination history. However, the benefits of regular tetanus boosting throughout adult life are sufficient to justify the costs of an administration programme and potential sensitivity reactions.

Human anti Rrabies immunoglobulin

The administration of anti Rabies immunoglobulin (RIG) complements Rabies vaccination in situations where viral transmission may have occurred, as production of vaccine-induced neutralising antibodies take seven to 10 days after vaccination. RIG is safe and provides rapid passive immunity that persists with a half-life of approximately three weeks.

The human RIG currently used in South Africa is produced by fractionation of pooled serum from immunised persons. The introduction of human RIG proved a valuable replacement to the previously used anti-Rabies serum prepared in horses. Although the latter was effective and is still used in many developing countries, it may induce serum sickness. To ensure between 2 and 8°C during handling and storage. All patients who have received RIG should be observed for an hour thereafter. An emergency pack for treating anaphylaxis should be available.

The dosage of human RIG currently available in South Africa is 20 International Units (IO) per kg body-mass. RIG is supplied in 2 ml ampoules with a virus-neutralising antibody content of 300IU. Preferably the complete dose of RIG should be infiltrated into the depth of the wound or tissue immediately adjacent to the wound. Where this is not anatomically possible, the remaining RIG may be injected intramuscularly into the deltoid muscle. RIG was traditionally administered into the buttocks, but there is evidence of low circulating Rabies neutralising anti-Rabies following RIG injection into gluteal fat. With multiple wounds, where the dose of RIG based on body mass is insufficient to infiltrate all wounds, the dose must be diluted up to 50% in saline to allow infiltration of all wounds. Failure to infiltrate all wounds is believed to have contributed to the deaths of a number of children. Local anaesthetic agents should not be used to facilitate RIG administration.

RIG is administered on the day of initial patient presentation, traditionally referred to as a day 0, with the first dose of vaccine but at separate injection sites. This is irrespective of the time elapsed since exposure, which represents a departure from the previous recommendation that RIG should only be given to patients presenting within a week of exposure. If RIG is not available when vaccination is initiated, it may be administered up to day 7 after the administration of the first vaccine. RIG administration is not recommended prior to vaccination, nor is it currently recommended for individuals who have received pre-exposure vaccination as it is believed that RIG may interfere with the rapid anamnestic response to vaccine.

Rabies vaccines

Rabies vaccine, when given post-exposure, induces immunity within seven to 10 days. Two cell-culture vaccines are currently registered for use in South Africa, i.e. purified chick embryo cell culture vaccine (PCECV) and purified Vero-cell Rabies vaccine (PRVR), and are highly purified and inactivated vaccines that meet the WHO potency standard of greater or equal to 2,5 IU per dose.

All persons judged to be at high risk for Rabies exposure should be vaccinated, with treatment being initiated as soon as possible even if there has been a delay in presentation to the health service. The treatment/prophylaxis schedules presented here are based on the most recent WHO recommendations, and are valid for the cell-culture vaccines registered in South Africa. However, it must be emphasized that the Essen intramuscular regimen is the only recommended schedule and administration route for South Africa, and expert advice should be sought before using an alternative regimen. The vaccination schedule may be discontinued if the suspected source animal remains healthy for 10 days after the exposure or if an approved veterinary laboraoty reports the brain specimen from the animal as negative.

Rabies Legislation

Human Rabies and the law

There are a number of important legal considerations relating to the diagnosis, management reporting of Rabies in humans in South Africa.

Negligence

When deciding whether a doctor has been negligent the court issues whether the doctor concerned acted as a “reasonable medical practitioner would have done under the same circumstances”. Four questions are usually considered; if the first two are satisfied then the accused person is said to have owed the injured person a “duty of care”. Whether this has been breached is determined by answering the next questions.

The questions are:

  • Would a reasonable medical practitioner in the same position have foreseen harm?
  • Would a reasonable medical practitioner have taken steps to guard against occurrence of harm?
  • What steps would a reasonable medical practitioner have taken to prevent the harm?
  • Did the accused take these steps?

The more serious the potential results, and the greater the likelihood that harm will occur, the greater the possibility that the courts will impose a duty of care.

Therefore, with the existence of national guideline on the management of persons potentially exposed to Rabies in South Africa, breach of these guidelines, for example failure to adequately treat the wound, failure to notify a state veterinarian or police officer about the existence of a potentially rabid animal, failure to complete the correct regimen of post-exposure prophylaxis, would most likely be considered unreasonable care and therefore negligence.

The Health Act (Act No. 63 of 1977)

In terms of section 45 of the Health Act (Act No. 63 of 1977) Rabies is a notifiable disease. It is therefore required that the responsible local or provincial authority and state veterinarian be informed of any human tabbies case, death or contact on the prescribed form, GW17/5/ Rabies is unique as it is the ONLY notifiable disease where contact by a person with an infected animal is also notifiable.

Post mortem

A suspected Rabies should be considered as due to an unnatural cause. A definitive diagnosis is of particular importance where an animal owner may be liable for not ensuring that his/her dog or cat was vaccinated according to legal requirements. A post-mortem should be requested and although relatives should be counselled, consent to conduct the post-mortem is not necessary.

Animal Rabies and the law

The Animal Diseases Act (Act No. 35 of 1984) provides for the control of specific animal diseases and for measures to promote animal health. The Minister of Agriculture may make regulations for accomplishing the purposes of the Act and has determined that Rabies control measures should be applied throughout the country. The decision was based on the geographical distribution of animal Rabies cases diagnosed over a five year period from 1995 to 1999.

The Animal Disease Regulations identify Rabies as a controlled animal disease.

The information in this article comes from The Guide for the Medical, Veterinary and Allied Professions compiled by the Department of Agriculture, Forestry and Fisheries, Republic of South Africa.

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Pregnant women have to watch out for this bug carried by cats

Introduction

Toxoplasma gondii is a tiny organism, slightly bigger than a bacterium, called a protozoa. This parasite has a worldwide distribution, except in the absence of cats. Cats are the only animals capable of completing the life cycle of this organism. Other warm blooded animals, including cats can serve as intermediate hosts for the parasite. The organism has a very high prevalence, but rarely causes clinical disease in dogs and cats. This is an important parasite to be aware of due to the fact that it is an important zoonosis, meaning it is an animal disease that can be transmitted to humans.

Life Cycle

Cats are the only hosts capable of passing oocysts, or eggs, of the Toxoplasma parasite in their stool. These eggs are environmentally resistant and can stay in the environment for an extended period of time. They are even resistant to multiple disinfectants. Once these eggs are ingested by a cat, they penetrate the gut lining and start replicating inside cells. More eggs will form and be released into the cat’s stool. Sometimes the eggs will penetrate deeper into the gut wall and develop into a more active form called tachyzoites that replicates quickly and may cause a slight small intestinal diarrhoea. In other animals like the dog, eggs will not be excreted, and the active parasite will form tissue cysts inside cells of the body. The active parasites replicate rapidly in the cells of the liver, lungs, pancreas and nervous system. These cells are destroyed by the rapid replication and this leads to clinical disease and even death of the host animal.

When the immune response is adequate it slows down parasite replication and they go into a dormant, or resting phase by forming cysts inside tissues of the host’s body. Parasites inside the cysts divide slowly. These cysts usually form in tissue of the central nervous system or muscle. Animals either get infected by ingesting eggs shed in stool of cats or by ingesting cysts in the tissues of infected animals. Cats do not commonly eat their own stool (called coprophagia), and are usually infected through ingestion of tissue cysts of infected animals when they hunt. It has been noted that mice infected with tissue cysts become fearless of cats and therefore become easy prey. Kittens can be infected through the placenta or through the milk when they are suckling from the infected mother. The infection in kittens is often severe and they can die acutely from infection involving the liver or lungs.

Symptoms of Toxoplasma

Most cats infected with Toxoplasma will not show any signs of the disease. Cats that do show signs of disease often suffer with underlying infections of other viruses like feline leukaemia virus, feline immunodeficiency virus or feline infectious peritonitis. These infections impair their immune systems and prevents it from controlling the disease in the early stages. This is also true for immuno-compromised dogs such as those infected with canine distemper. The first clinical signs or symptoms that cats will show include depression, loss of appetite and fever. Later on as the disease progresses and depending on where the organisms are located they can become hypothermic (low body temperature), the abdomen can fill with fluid, they can become jaundiced (yellow) and may battle to breath.. Dogs and cats can become chronically infected and will show signs of eye infections (uveitis), muscle twitching, balance problems with swerving of the hindquarters (ataxia), seizures, pancreatitis and jaundice otherwise known as icterus. The neurological signs depend on where the tissue cysts form and how big they get. Muscles may also be affected together with the central nervous system and can lead to a stiff gait, weakness of voluntary movement (paresis), total loss of muscle function (paralysis), and seizures.

Diagnosis of Toxoplasma

Toxoplasma is difficult to diagnose due to infected animals often now showing any signs of the disease and because of the non-specific symptoms infected animals that do show signs have. Basic laboratory tests of the blood will give non-specific results like low red blood cell count or anaemia, increased or decreased white blood cells counts, protein in urine, increased liver and kidney enzymes. None of these results are specific to this disease. The only way a definite diagnosis can be made is by detecting the antibodies to the organism in tissue fluids like lung fluids and cerebrospinal fluid. Sometimes the eggs can be found in a cat’s stool, but this is not a very reliable way to make a diagnosis as the eggs cannot easily be distinguished from worm eggs and a cat will not always be shedding eggs at the same time he or she is showing clinical signs. Measurement of antibodies called IgG and IgM in the blood can help support the diagnoses of Toxoplasma when the patient is showing clinical signs related to Toxoplasma infection but due to the fact that healthy cats can also show high levels of both IgG and IgM, it is not a reliable method of diagnosis.

The most reliable method to make a diagnosis currently is to show high levels of IgM in cerebrospinal fluid of a patient showing related clinical signs.

Treatment of Toxoplasma

Supportive care for very ill patients is important and treatment should be started as soon as possible. The treatment of choice is an antibiotic called clindamycin but there are other combinations of antibiotics that can be used as well. Patients usually respond quickly to treatment, and failure of improvement of clinical signs within a few days usually means the diagnosis should be questioned.

Spread to humans

The most common way humans get infected is through contaminated soil. Unwashed fruit and vegetables can play a big role, as well as eating uncooked meat, especially lamb and pork. Another way of getting infected is by ingesting unpasteurised dairy products, especially goat’s milk. Mothers infected with Toxoplasma while pregnant can lead to clinical Toxoplasmosis in the foetus through transplacental infection. This can cause stillbirths, central nervous system disease and eye disease. Pregnant woman should not clean cat litter boxes or do gardening or if they have to, always wear rubber gloves. They should only eat cooked meat and wash fruit and vegetables well before use. It is also useful to keep children’s sandboxes covered to prevent cats soiling it. Due to the high prevalence of the disease it is difficult to prevent infection in cats. The only way will be to prevent cats from roaming and hunting, which is an almost impossible task! Clinical disease is also noted in immuno-compromised patients such as those with HIV and cancer. In these patients nervous system may be affected and people can die from an infection with Toxoplasma.

As with all matters related to pets, the general principles of hygiene must always be observed and regular visits to the vet for annual health check-ups and vaccinations where and when relevant, will help detect potential problems early on, so one can act pro-actively if need be.

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