The Feline Immunodeficiency Virus is a slow virus that affects a cat’s immune system over a period of years. FIV is a cat-only disease that cannot be spread to humans or other animals. FIV cats most often live long, healthy, and relatively normal lives with no symptoms at all.
The disease has a wide range of effects. The cat can fight off the infection and become totally immune, can become a healthy carrier that never gets sick itself, or a mid-level case in which the cat has a compromised immune system.
FIV is not easily passed between cats. It cannot be spread casually – like in litter boxes, food and water bowls, or when snuggling and playing. The virus can be spread through blood transfusions, badly infected gums, in-utero from mother to offspring, or penetrating bite wounds (typically associated with unneutered tom cats). A neutered cat in a home is extremely unlikely to infect other cats, if properly introduced.
FIV-positive cats should be kept as healthy as possible, feeding them a high quality diet. As with all cats, they should be kept indoors and free from stress. Treat any secondary problems, such as an upper respiratory infection, as soon as they arise.
FIV is difficult to transmit; the main route is via a bite where the virus is actually injected into the bloodstream.
There is often confusion between FIV and FeLV; this is particularly the case regarding the transmission of the virus.
The FIV virus is present in the saliva, and for transmission to another cat to take place, the live virus has to enter the bloodstream of the recipient cat.
There are two main reasons why FIV isn’t transmitted via shared bowls or mutual grooming as is sometimes wrongly suggested:
Firstly the virus is very fragile, and does not live for long once outside the body. It is destroyed by drying, light, heat, and basic detergents. Normally, the virus will be long-dead before any surfaces come to be cleaned – it is the initial drying that kills off the vast majority of the virus, and this will usually happen in seconds.
This is why the route of transmission is primarily via a bite, where the still-wet saliva containing the live virus is effectively injected through the skin directly into contact with the blood of the recipient cat.
The second reason is that the mucous membrane is a fairly effective barrier to the virus, so even if some virus does enter the cat’s mouth, it is very unlikely to cross the mucous membrane, so will likely die within the stomach. It has been suggested that, for the virus to actually infect a cat when taken in through the mouth, there would need to be ten thousand times as much virus present for it to achieve a cross infection.
Interestingly, this is confirmed by the fact that kittens born to an FIV+ mother are rarely infected with the virus. although the kittens are not infected directly in the womb, as the placenta will protect them, the virus is present in the mother’s milk, so all kittens will have prolonged exposure to the live virus in their digestive systems, yet it is very uncommon for the kitten to actually become infected. This is a testament to how effective the mucous membrane must be in preventing transmission.
It is for these reasons that the often-prescribed “keep separate from other cats” is NOT valid. FIV cats can live communally with non-FIV cats with very little risk of the virus being transmitted between them, unless the cat is a fighter and gives another cat a serious bite, which is rare with properly introduced household cats. The vast majority of cats, once neutered, will not bite other cats they live with; they may play and scrap, but this rarely leads to the serious bite required to inject the virus. There are numerous examples of households with large numbers of cats living together with FIV-positive cats without the virus being transmitted. A slow and careful introduction is required when bringing any new cat into an existing household, especially so with an FIV cat.
Caring for cats with FIV or FeLV
The goal of caring for FeLV and FIV infected cats is to keep them healthy, detect problems early, and treat the associated diseases promptly and aggressively so that the cats can enjoy the maximum quantity and quality of life possible.