Biliary fever AKA Tick bite fever & “Bosluiskoors”

Biliary is a very common cause of deaths in dogs in SA. Commonly referred to as Tick-bite Fever or “Bosluiskoors” by most pet owners.  It is caused by a tiny parasite called Babesia canis which is introduced into the body by ‘n tick bite, on entering the body it destroys red blood cells.

Clinical signs of disease

The peracute (very sudden and severe) form causes death within a few hours and treatment is of little avail. More commonly dogs suffer from the acute or subacute form. This is recognised by the dog being listless or lethargic, losing its appetite and running a temperature. If your dog is off its food, take a rectal temperature reading. If this is 39 °C or higher you should have the dog examined – do not wait until its mucous membranes become pale, white or yellow, which commonly suggests a more advanced stage of the disease. Fever is present only while the patient is actively fighting the parasite; the disease may be present with a normal (38,5 °C) or subnormal temperature. Yellow faeces and brown or red urine also suggests the presence of biliary fever.


The diagnosis is done via a very simple test at the clinic.  A small drop of blood is collected and a smear made. Once stained, the parasites can be seen in the red blood cells under microscopic evaluation. When evaluating the blood smear, it is also important to check the white blood cells as there is another tick born parasite (Ehrlichia) that often occurs together with the biliary parasites. They often occur together as they are transmitted by the same ticks. This infection has similar symptoms to biliary and can also be found as an infection on its own.


Treatment should only be given after a positive diagnosis has been made by means of a blood test. Usually treatment is effective, depending on several factors, but the majority will respond. In early cases, simple injections are usually sufficient, but in others blood transfusions, electrolyte infusions per vein, liver tonics, blood-building, etc., may be required.

Prevention is better than cure!

Tips to avoid Tick-borne Infection:

  1. Use a preventative tick and flee product. There are many preventative tick and flee products available, ie Frontline, Bravecto & Nexgard.  It is best to consult your Vet about which treatment is best suited for your pet.
  2. Check for ticks regularly, especially in areas where ticks can hide, such as between the toes, the underside of the feet, in the earflaps and around the tail base.
  3. Remove ticks the right way. If you find a tick on your dog, be sure to remove it immediately, but carefully and safely. Always wear gloves and use a tick removing tool. Never pull, rather twist and “unscrew” the tick from the skin. It is important to remove the whole tick including its mouth. Once it’s off, flush it down the toilet. Then disinfect your dog’s skin with soapy water or diluted disinfectant. Monitor the attachment site for the next few days. If you notice any irritation or inflammation of the skin, contact your veterinarian.

Remember: Waiting until your dog exhibits symptoms isn’t the most proactive approach. Tick-borne diseases are harder to treat once a dog is clearly ill.