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  • Writer's pictureDrs. Frans, Bianca, Danielle & Rene

Bosluiskoors / Biliary Fever or Babesia by Dr. Danielle van der Ryst




What is Biliary Fever or Bosluiskoors and how is it transmitted?

Babesia is a parasite, that is transmitted via tick bites, that infects the red blood cells of dogs. These parasites replicate inside the red blood cells before rupturing the cells and moving on to the next cell.


What clinical signs can you expect?

As the parasites infect the red blood cells, the body will start to see these infected cells as foreign and as such will launch an attack on them. This attack results in the destruction of red blood cells.

Red blood cells are the main cell involved in the transport of oxygen and nutrients to the rest of the body.


Symptoms you can expect:

· Weakness

· Shortness of breath

· Fever

· Anorexic

· Anaemia

· Yellow or pale gums

· Dark red urine

· Other signs can include: Muscle pain, neurological signs, vomiting, renal failure and liver failure


Signs and symptoms may vary according to the degree of destruction of the red blood cells and your dogs’ ability to make new red blood cells. The most consistent signs are anorexia and weakness.

Normal gums:

Pale gums:

Yellow / Icteric gums:

How we make a diagnosis?

A diagnosis will be made with the use of a blood smear, that is viewed under a microscope and clinical signs. As the parasites associated with Babesia may not always be present when examined the first time follow-up microscope smears might be needed or even sent away to the lab to look for the parasite.



Once the diagnosis is made, we will need to evaluate the degree of red blood cell destruction by doing a few in house tests. This will also tell us if a blood transfusion is needed or not.

Sometimes we can get other tick-borne diseases in conjunction with Biliary, like Ehrlichia Canis or Bosluisbytkoors which will need to be addressed seperately.


Is there any treatment and or prevention?

Treatment will start with an anti-parasitic drug administered by your veterinarian to kill the parasites in the effected red blood cells. These drug can be very dangerous if used incorrectly and we always recommend treatment be done under the care of a veterinarian.

Depending on the degree of red blood cell destruction, your dog may need a blood transfusion or supportive care like intravenous fluids. If this is needed your dog might be very sick and will need to stay over at your vet for monitoring and further treatment, to prevent shock and further organ damage like liver failure or kidney failure.


Unfortunately, if the disease has been left to progress for too long or if there are any complications, your dog may still die, even if vigorous treatment is implemented.


As such prevention is of critical importance. Prevention is done by giving anti-tick and flea treatment.


There are traditional topical treatments like Frontline which has a residual effect for 1 month or oral options like:

· Bravecto

(effective for 3months)

· Nexguard

(effective for 1month)

· Simparica

(effective for 1month)

· Seresto collar

(effective for 8months but dog has to have the collar on at all times for effectivity)


Older remedies like dips only kill ticks that are on the pet at that moment and has no long lasting prevention.








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