Tick Bite Fever

Biliary Parasites are protozoan parasites (single-celled organisms) and they were first discovered at the end of the 19th Century.  Two sub-species occur in Dogs.

• Babsia Canis Rossi is transmitted by yellow dog tick (Hyaemaphysalis elliptica, previously known as H. leachi) and frequently results in fatal infections, even after treatment.  The kennel tick (Rhipicephalus sanguineus) may possibly also be involved in the transmission of B. canis rossi.
• Babesia canis vogeli is transmitted by the kennel tick and most commonly results in subclinical (inapparent) infections.

The tick becomes infected when it ingests infected red blood cells (containing daughter cells) by taking a blood meal from an infected dog.  The biliary parasite reproduces sexually within the tick and the sporozoite stage of the biliary parasite then becomes localised within the salivary glands of the tick. Actual transmission of the biliary parasite from the tick to the dog therefore only occurs a few days (48 hours) after the tick has attached.  Within the dog the biliary parasites infect the dog's red blood cells, where asexual multiplication takes place, resulting in 2 (sometimes 4 or rarely 16) daughter cells.  These infected red blood cells rupture and each individual daughter cells re-infects a new red blood cell.

The signs can be divided into uncomplicated (typical) and complicated (atypical).

Uncomplicated

The uncomplicated form involves, listlessness, loss of appetite, fever, jaundice (yellow discolouration of the gums and the inner eyelids), collapse, pale mucous membranes of both the gums and the inner eyelids (this may be masked by jaundice); red wine coloured urine, enlarged spleen, and increased heart rate and respiratory (breathing) rate.

Complicated - Organ involvement

These complicated cases arise due to the dysfunction of multiple organs including the kidneys, liver, lungs, brain, immune system, stomach and intestines, pancreas, muscles and blood system.  A concurrent ehrlichiosis infection, caused by Enrlichia canis is another complicating factor.  Ehrlichiosis is a disease that is transmitted by the kennel tick.  Signs of an ehrlichiosis infection may last either a few days (acute) or even a few weeks to months (chronic).  The acute form involves all of the above as well as bleeding tendencies and even other concurrent infections.  Concurrent babesiosis and ehrlichiosis infects are possible, as the kennel tick and the yellow dog tick have overlapping distributions and have been collected from the same hosts.

These complicated cases don't simply recover with the injection of an anti-protozoan drug.  Additional treatment may involve any of the following: blood transfusion; oxygen supplementation; fluid therapy; glucose supplementation;  fluid therapy; glucose supplementation; potassium supplementation; cortisone treatment; liver supportive treatment; treatment to try and promote urine production in cases with kidney failure; further kidney supportive treatment; plasma transfusions; nutritional support which may include tube feeding; attempted treatment of cerebral cases with oxygen, sedatives and drugs to decrease the brain swelling, anti-inflammatory drugs; pain killers; mechanical ventilation.

These complicated cases are considered common by approximately  26% of veterinary practitioners in South Africa.  Deaths due to biliary, caused by B. canis rossi, frange from approximately 5 - 7% among admitted cases.

Dr Sunelle Strydom qualified as a veterinarian in 2004 at the Faculty of Veterinary Science, University of Pretoria.  She has a passion for writing and the sharing of knowledge to promote animal health and welfare.  She has written several articles for KUSA Dogs in Africa as well as for Vra vir Faffa on the Landbouweekblad website at www.landbou.com

For additional information on Biliary

Other articles which may be of interest:

Itchy Dog

Dog Mites

Ticks

Dog Health Conditions