It has the potential to interfere with the cat's immune system and can be fatal.

The virus is in the same class as the HIV virus that affects people, but FIV is not transmissible to humans.

About 30 per cent of cats carry FIV. It is transmitted mainly through bite wounds.

This means cats that are often outdoors, which are more likely to roam and therefore more likely to get into fights with other cats, are more at risk.

Once infected, the virus lives in the cat's blood stream and is carried by the cat for the rest of their life.

Some cats that are FIV positive never show any sign of disease.

This is why the virus spreads so quickly, as cats that are not known to be infected are let roam around and then fight and spread the virus.

The first symptoms of FIV in a cat are often non-specific. They include fever, lethargy, loss of appetite, diarrhea and swollen lymph nodes.

These can progress further to weight loss, sores in around the mouth and other ongoing infections. The cat's immune system becomes so weak that the condition can become fatal.

There is no immediate treatment for FIV, only the secondary infections can be treated.

Luckily, FIV is preventable. It's recommended a vaccination is given to all cats that have contact with the outdoors.

If you have an adult cat that has never been vaccinated, your vet will do a quick blood test to ensure your cat does not already have the virus.

Then it is three injections of the vaccination given at two-week intervals. After this, initial course the vaccination should be given yearly.