TARASCANI MAINE COONS

What is FIA?:

Feline infectious anaemia (FIA) is the term used to describe the disease caused by a single-celled parasite called Haemobartonella felis (H. felis, previously known as Eperythrozoon felis) which attaches itself to red blood cells in the cat's body. The cat's own immune system tries to destroy these parasites but, in the process, also destroys the infected red blood cells, causing anaemia.

The H. felis organism is neither a bacteria, a virus or a protozoa (a protozoa is a single-celled animal). It attaches loosely to the membrane of a red blood cell but does not penetrate it. However, on passing through the cat's liver and spleen, the infected red cell is removed from the circulation and destroyed. It is not absolutely clear if the parasite is also destroyed by this process, or if it is able to move onto a new red cell.

Recently, it has been discovered that there are actually two distinct species of haemobartonella organisms that infect cats. These species are collectively known as the feline haemoplasmas and the new names given to the two species are Mycoplasma haemofelis (sometimes called the large strain) and Candidatus Mycoplasma haemominutum (sometimes called the small strain). It is important to be aware of the differences between these species as they have very different effects in cats. M haemofelis often results in anaemia in cats while Candidatus M haemominutum often causes no clinical signs at all.

What are the Symptoms of FIA?:

Because the cat's immune system destroys the infected red blood cells, the cat will suffer from anaemia. If severe enough, it will result in a noticeable paleness to the mouth and conjunctiva (The conjunctiva is the pink membrane that surrounds the eye).

The classical symptoms of this disease are:

• Raised body temperature (and fever in the early stages of infection)
• Loss of appetite
• Anaemia
• Lethargy

Over time these symptoms progress to weight loss and, in the more severe cases, the cat can become jaundiced. Jaundice is easiest to see in the whites of the eyes, which take on a characteristic yellow discolouration. It is caused by the build-up of waste blood pigments in the body.

The cat's spleen may become enlarged, which is often detected by feeling the cat's abdomen, or by x-ray. The breathing may become faster and deeper as the cat tries to compensate for a reduction in the oxygen-carrying capacity of the blood.

M haemofelis can cause anaemia in normal healthy cats. Candidatus M haemominutum may be more of an opportunistic pathogen, causing disease in cats which are stressed or ill due to other diseases, since it has been found that cats infected with feline leukaemia virus (FeLV) or feline immunodeficiency virus (FIV) can develop anaemia due to Candidatus M haemominutum infection.

How is FIA Transmitted?:

Older male cats are most likely to be infected, and fighting is believed to be one of the ways that the parasite may be transmitted between cats. Cats infected with fleas may also be at an increased risk because fleas may transmit infection between cats.

It is also thought likely that transmission from mother to kitten can occur before birth. The situation is complicated by the fact that a high proportion of infected cats can carry the infection without showing any signs of ill health and the absolute diagnosis of the condition is not easy.

Saliva and urine are not thought to be able to transmit the disease.

How is FIA Diagnosed?:

The definitive diagnosis of this condition is quite important as it has serious implications for the long-term health of the cat. Most cats with FIA are noticeably pale on the first examination by a veterinary surgeon. Under these circumstances, a blood test is essential to discover the underlying cause because there are many possible causes of anaemia. At this stage, the most appropriate tests are for haematology (which counts the number of each different types of blood cell), feline leukaemia virus (FeLV), and feline immunodeficiency virus (FIV). Both of these viruses can cause anaemia on their own, and are more common than H. felis. I t is also possible to be infected with FeLV and/or FIV at the same time as H. felis. In these circumstances, the anaemia is likely to be much more severe than with either agent alone and the outlook is much poorer.

Up to 50% of cats that are infected with H. felis will show a falsely negative blood test result. This is because the number of parasites present in the blood varies with time in any individual.

How is FIA Treated?:

• Antibiotics

  Although H. felis is not a bacteria, it is susceptible to a number of antibiotics. It has been shown that although antibiotics can be effective at treating the anaemia, they do not always eliminate infection and cats can remain chronic carriers for a long time. Such carrier cats can appear healthy without clinical signs, but relapses are commonly reported at times of stress.

• Blood transfusions may be required in cases of severe anaemia. Supportive care to encourage the cat to eat and rehydration therapy, in dehydrated cases, are also important.
• Immunosuppressants

  Some cats develop an immune-mediated component to the disease. This means that antibodies are produced against the red blood cell itself, and even normal red blood cells are destroyed. In this case an immunosuppressant drug needs to be given in addition to the antibiotics. This is a steroid hormone with a wide range of effects. It will often cause an increase in appetite and thirst, although cats tolerate steroids very well, especially for the short duration of treatment that is used in this instance.

How can FIA be Prevented?:

Fleas are strongly suspected as being the main method of transmission, and it is therefore essential that all cats that may come into contact with fleas, or other cats that have fleas, are treated with an effective preparation to prevent infestation. In the UK, this practically means any cat that goes outdoors, or that lives with another cat that goes outdoors, should be treated for fleas regularly. Flea collars are not an effective means of flea control. It is also important to keep infected cats away from non-infected ones.

Infected cats should not be used as blood donors.

Outlook for Affected Cats:

In the case of cats co-infected with FeLV/FIV and H. felis, the outlook is very poor. Treatment with the antibiotics mentioned above may help in the short term, but if the cat is severely anaemic, with a poor quality of life, then euthanasia may be the best option.

In the case of cats infected with H. felis alone, the outlook is very much better. Most cases will respond to treatment very satisfactorily, although the possibility of a relapse some time in the future is very real.