Is Tick Fever and Tick Bite Fever the same disease in dogs?
It is not. Tick fever or Babesios in dogs, is not the same disease as Tick bite fever or Erlichioses. Both diseases are transmitted to dogs by ticks, but they are caused by two totally different organisms or parasites and the clinical signs, progress and treatment are very different.
To further confuse the matter, Tick Bite Fever in humans is not the same as Tick Bite Fever in dogs and once again, although transmitted by ticks, is caused by a complete difference parasite. Tick Bite Fever in dogs is not transmissible to humans or vice versa.
So what is Tick Bite Fever in dogs and how can it be treated, and better yet, prevented?
Erlichiosis is a disease of the domestic dog and is common in the warm climate of South Africa. It is a tick born disease, meaning dogs can get infected when an infected tick bites and feeds on them. The organism that is responsible for this disease is called Erlichia canis, but there are many different Erlichia species worldwide. Erlichia is neither a bacteria nor a virus, but rather something in between the two. When a tick feeds on an infected animal, the organism gets transferred to the tick. The tick can carry this organism for up to 5 months and infect many animals as they feed on them. Specific tick species carry this disease and Erlichia is prevalent in areas where these ticks are found. This disease is known worldwide and was studied extensively after the war in Vietnam when hundreds of military dogs succumbed to the disease. It was found that German Shepherd dogs are more susceptible and suffer more severely from this disease.
There are three phases in the disease process:
- Acute phase: The acute phase develops within 1 to 3 weeks after the bite. During this phase the organism enters and multiplies within a certain type of white blood cell, called monocytes. The clinical signs are caused by a widespread vasculitis or inflammation of the veins in the body. It causes blood cell loss or anaemia, and decreases the platelet count. Platelets are responsible for clotting of blood in the body. Signs to look out for during this phase are weakness, lethargy, depression, anorexia and enlarged lymph nodes.
- Subclinical phase: This can last for months to years without any clinical signs noted by owners. During this phase, the animals’ immune system can clear the infection, but if not, it will progress to the next phase.
- Chronic phase: The mortality rate can be high in this phase of the disease. Bone marrow suppression (the body’s blood cell factory) and haemorrhage or bleeding are the main causes of the clinical signs. Signs shown are nose bleeds, or any other form of bleeding and bruising. Severe weight loss, fever, difficult breathing, joint pain with inflammation, neurological signs, kidney failure, eye problems and paralysis, to name a few. If the disease is not treated, it will progress to overall organ failure and death.
Diagnosis and treatment
Because of the non–specific nature of the clinical signs, making a diagnosis of Erlichiosis is not straightforward. A detailed history of your dog’s health, whereabouts and living conditions are extremely important in the diagnostic process. A thorough clinical exam should prompt the vet to do further diagnostic steps to get to a diagnosis. The most basic diagnostic tool is a blood smear. A drop of your pets’ blood is smeared thinly onto a glass slide, stained and then examined under the microscope. The organism multiplies in the white blood cells of the affected animal, and can be seen as a purple inclusion body (almost like a bunch of grapes) in the cytoplasm of a specific type of white blood cell called monocytes. Unfortunately, inclusion bodies are not always visible and very few dogs are dibagnosed this way, therefore other means of detection are needed. Detection of antibodies in the blood is a common way of diagnosing infection and can be done by sending blood to a lab facility. Even this is not 100% accurate and can sometimes give false positive results. Your vet will often look at a full blood count of your animal, and together with the history, clinical presentation and lab tests, will make a diagnosis of Erlichia. Response to treatment is also an important tool to make a final diagnosis. Erlichia is treated with an extended course of doxycycline, an antibiotic. Treatment needs to be continued for at least 4 to 6 weeks. If treatment is stopped prematurely, the disease can continue to the chronic stage.
The saying, “prevention is better than cure”, rings true in this case. Because the disease is transmitted through tick bites, it can to a large extent be prevented through proper tick and flea control. Speak to the vet on your next visit about which products he/she recommends for tick control.
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