Feline Infectious Anaemia

What causes feline infectious anaemia (FIA)?

FIA is caused by a very specialised group of bacteria called mycoplasmas, which attack the cat's red blood cells, leading to anaemia. There are many types of mycoplasmas which vary in their severity with some causing no clinical signs at all.

How would an owner recognise FIA in the cat?

Cats are very good at hiding anaemia until it is quite severe. The earliest indication may be pallor of the mucous membranes; the conjunctiva (lining of the eye), gums, and tongue appear white or pale instead of the normal pink colour. It can be difficult to assess the mucous membranes in some cats because compared to dogs and people even in normal cats their gums can appear quite pale. Anaemia is not the only cause of pale gums; anything that causes the blood pressure to fall may give the gums a paler than normal colour.

Another indication of anaemia can be ‘pica’ where the cat likes to eat unusual things and may be noticed licking stones or eating its cat litter. As the anaemia becomes more severe the cat may become lethargic and breathless if stressed or exerted. In FIA a poor hair coat, poor appetite, weight loss, high temperatures, occasionally jaundice may be seen.

How is FIA diagnosed?

In the past, the diagnosis of FIA was based on finding the organism on specially prepared and stained blood films however this method is very unreliable. A test that detects the DNA of the organism in the blood is now available from some veterinary laboratories. This test also determines which type of mycoplasmas is present and the amount of the DNA which can help to determine whether or not the infection is likely to be significant.

Can FIA be treated?

FIA is treated with specific types of antibiotics. The treatment is very effective but the drugs do not reliably eliminate the parasite from the body. Sometimes infection can recur once treatment is stopped so careful monitoring of blood tests is required. In severe cases where the cat becomes weak due to very severe anaemia, a blood transfusion may be required.

Does a diagnosis of FIA have any implications for my other cats?

Although FIA is a disease caused by an infectious agent, it may not prove to be a problem in other cats living in the same household. The way it is spread between cats is not certain. Cat bites and fleas may spread the parasite but other methods may also be involved. Attempts to reduce fighting between cats in the household and rigorous flea control are important in reducing the risk of spread of this infection. Heavy flea infestations may also make anaemia more severe, particularly in kittens.