Blood parasites in cats

In the context of South African companion animal veterinary medicine, blood parasites are frequently seen in dogs. Most have at least heard about “Biliary” or “Tick-bite Fever” and, seasonally, it appears to reach epidemic proportions. But what about cats? Do they run a similar risk? Two diseases are of serious concern.

Feline Infectious Anaemia: This sneaky disease is caused by a bacterium called Mycoplasma haemofelis and is transmitted to cats through fleas, tick or mosquito bites. Mycoplasma then follows a similar strategy to parasites, attaching to red blood cells of the host. In response to this your cat’s immune system then attacks and destroys affected red cells. Once a critical level of red blood cells has been destroyed, patients start to display clinical sings of anaemia (pale or yellow mucous membranes, lethargy, anorexia and weight loss). Frustratingly, this organism may remain unnoticed for weeks and diagnosis through blood smears or external laboratory tests remain problematic. Fortunately patients respond well to, albeit prolonged, antibiotic and corticosteroid therapy. Proper flea and tick control and prevention, however, remains the first and most important weapon of choice.

Mycoplasma (Fig 1)

Mycoplasma sp. (Photo courtesy of Lab.Med.Vet)

Feline Biliary: Caused by Babesia felis (not the same parasite found in dogs), Biliary once again follows a silent route until finally detected. The parasite is transmitted by ticks and causes vague signs of anorexia, lethargy and weakness. Patients may appear unkempt and not as thoroughly groomed as expected. Fortunately this disease appears to be limited to coastal areas and local cats appear to harbour a degree of immunity. Inland cats, visiting coastal areas with their owners, are at particular risk as are any cats suffering from immunosuppressive disorders such as feline leukaemia virus (FeLV) or feline immunodeficiency virus (FIV,feline AIDS). Diagnosis, once again, remains problematic. Parasites affect and inhabit red blood cells and assistance by external laboratories is required for a firm diagnosis. Patients discovered to harbour the parasite, respond well to treatment, but must be discovered in time. Patients suffering from FeLV or FIV show a typically poor response and carry the worst prognosis.

Babesia felis

Babesia Felis (Photo courtesy of StudyBlue)

Both these diseases are unfortunately prevalent in our region and need our attention. Prevention through the application of appropriate tick and flea control, remains paramount in these cases.