Overview

There are many infectious diseases that may cause anemia in cats. The disease most commonly known as “feline infectious anemia” is caused by a parasitic bacterium (Mycoplasma haemofelis), which infects the red blood cells of the host and result in anemia when the host’s immune system begins to attack the affected red blood cells. The bacterium is transmitted via fleas, ticks, lice, or mosquitoes, as well as through fighting-related injuries. Outdoor cats, cats with a history of fighting, and cats with incomplete vaccination histories are especially at risk. The disease often appears in conjunction with feline leukemia virus, possibly because the compromised immune system allows the parasitic bacterium to reproduce more rapidly. However, normal cats with healthy immune systems are just as likely to contract feline infectious anemia..

It can take up to a month after initial infection for symptoms to appear; in the month after symptoms first present themselves mortality can be very high, and relapse after recover is possible if the cat is subjected to excess stress.

The disease is recently re-named to “feline hemotropic mycoplasmosis” to distinguish it from other infectious, anemia-causing diseases, as well as to reflect the agent that causes the infection. However it is still most well-known as feline infectious anemia. There is a similar disease in dogs, however at this time the evidence suggest that the infection cannot spread across the species line.

Symptoms and Diagnosis

In mild cases symptoms include loss of appetite and lethargy. More seriously anemic cats are pale in the mucus membranes, and may appear jaundice. Weight loss, rapid heart beats and rapid respiratory rates are other signs of severe anemia. Some cats may start eating dirt and litter in attempt to replenish the iron content in their blood. Blood tests will show low red cell counts and very active bone marrow – a sign that the animal is compensating for the loss of red blood cells.

Diagnosis can be difficult since the bacterium in question lacks cell walls and therefore cannot be cultured. Repeated observations of blood samples are necessary in order to detect the presence of infected red blood cells. PCR tests are the most reliable in detecting feline infectious anemia.

Treatment

Antibiotics such as doxycycline or enrofoxacin can be used to eliminate the bacterium from the bloodstream. The full course of treatment generally last for three weeks. Sometimes an immunosuppressant is also used in order to stop the cat’s immune system from attacking its own red blood cells. In very severe cases blood transfusion is required. While recovered cats might become carriers of the disease, prognosis is generally very good if symptoms are caught in time.

Cats that are kept indoors and have regular vaccinations are generally much less likely to contract this disease.