Haemobartonellosis

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  Feline Infectious Anemia (FIA), the Result of Haemobartonella Infection

Feline Infectious Anemia (FIA) is a blood disease of cats caused by a microscopic parasite called Haemobartonella felis (H. felis). Because of the organism’s name, this disease is also sometimes called haemobartonellosis. This organism attaches to the surface of the cat’s red blood cells, where its presence is eventually detected by the immune system. Once the immune system recognizes the parasite, it attempts to eliminate it by destroying the red blood cells. With destruction of a large number of red cells, anemia may result.

Contributing Factors

Identified risk factors for FIA include anemia, positive feline leukemia virus (FeLV) status, positive feline immunodeficiency virus (FIV) status, access to the outdoors, a history of cat-fight wounds, and lack of vaccinations. Male cats are probably at greater risk.

Cats with FIA should be screened for the presence of immunosuppressive viruses. The primary viruses are FeLV and the FIV. These viruses can serve as stresses which promote development of FIA. If one or both of the viruses is found, the prognosis for recovery is more unpredictable than in the virus-negative cat.

Prevalence

The true prevalence of the disease is unknown because of the difficulty in identifying the organism and its inconsistent presence in the bloodstream. The prevalence is higher in sick cats than in healthy cats. Estimates of its presence in sick cats ranges from 0 – 28% of cats examined.

Clinical Signs

Reported clinical signs include depression, weakness, jaundice, weight loss, anemia, enlargement of the spleen, and death.

Causes/Transmission

Although the method of transmission has not been conclusively demonstrated, it is thought to be spread between cats by blood-sucking insects and, possibly, by wounds from cat fights. Experimentally, the organism has been transmitted between cats by blood transfusion. Newborn kittens may be infected, but it has not been proven if the infection is established through the placenta, during birth, or by nursing the mother.

Diagnosis

Because H. felis can be found on the red blood cells of healthy cats, detection of the organism does not always equate with a diagnosis of FIA. In many cases of FIA, the cat has a concurrent disease or another form of stress. This state of debilitation then triggers H. felis and allows the development of FIA.

Diagnosis of this disease is made from a fresh blood smear which is stained and examined microscopically. If the cat is anemic and large numbers of H. felis are present, the diagnosis of FIA is made. Unfortunately, H. felis is not always present on the cat’s red blood cells because it appears in the blood stream in cycles. If FIA is suspected, it may be necessary to examine several blood samples before H. felis is identified.

Treatment

Treatment is relatively simple and usually successful. Most often, medications in the tetracycline family are used. The drugs are not expected to clear the organism completely but, instead, suppress it’s replication in the cat’s body. Drugs in this group should be given in a liquid formulation to cats. If the cat is given these drugs in tablet from and does not completely swallow the tablet, an esophageal stricture may develop. At the Animal Clinic at Thorndale, we generally will write you a prescription to have the medication formulated in a “cat friendly flavor” liquid. That way you can be certain your cat is taking the medication.

Additional treatments may involve a blood transfusion for severely anemic cats, as well as prednisone for temporary suppression of immune-destruction of the red blood cells.

Prognosis

If treatment is not initiated in the acute phase, up to one-third of all cats with FIA will die. Cats who recover from the early stages of the disease will become chronic carriers of the organism and are thought to be susceptible to relapse with periods of stress or illness. With chronic infection, it may be impossible to detect the organism in the blood because it is present in such low numbers.

Transmission to Humans

This disease is not transmitted to humans.

Prevention

Although there is no way to prevent the disease, chances of contracting the disease may be lessened by keeping cats indoors, preventing fight wounds, providing appropriate vaccination against other diseases, and controlling fleas and ticks.