Feline Immunodeficiency Virus, abbreviated as FIV, is sometimes referred to as feline AIDS. This is a bit of a misnomer.
FIV is actually a feline immunodeficiency virus, a retrovirus which attacks the immune system much like HIV does in humans.
Feline AIDS is a different condition, just as AIDS in humans is different from HIV in humans.
It is important to note that although these viruses have similar names, and are in the same family, they cannot be transmitted from cat to human, or from human to cat. These viruses are what is called “species specific,” meaning that they can only infect one species of living organism.
This does not mean that humans cannot catch any diseases from cats: when a cat that has developed a secondary infection because of feline AIDS, toxoplasmosis for example, there is a possibility that disease can be transmitted to humans.
FIV is, however, contagious to other cats. FIV is usually spread from one cat to another during fighting when one cat bites another. It is more common for male cats to have FIV since they are more susceptible to fighting. Indoor cats are also far less likely to catch FIV because they are exposed to fewer other cats.