What is FIV in cats? FIV stands for feline immunodeficiency virus. It is a lentivirus, the same class of virus as HIV. FIV, which can live in many different tissues in cats, typically causes a weakening of the cat’s immune system. How do cats get FIV? One of the tissues in which FIV lives is the salivary glands, so the most common route of infection is a deep bite wound from a FIV-positive cat to another cat. It can also be transmitted via blood, in utero and possibly from milk from an infected mother cat. It is extremely unlikely, if not impossible, for cats to get FIV from just being around infected cats, from sharing food bowls, or from a person touching a FIV-positive cat and then touching a FIV-negative cat. What are the signs of FIV infection? There are no specific signs of FIV infection. FIV-positive cats have a weaker immune system so they are more prone to getting infections such as upper respiratory infections, ringworm and dental disease. Other than that, FIV-positive cats tend to live normal lives and have a normal length of life. How do I know if my cat has FIV? There are no obvious signs of FIV so the only way to know is to do a blood test. The most common screening test is an ELISA test (often called a SNAP test) done by your veterinarian, which looks for antibodies to FIV.
An antibody is a protein made by the cat in response to FIV infection. A cat can test positive as soon as two to four weeks after exposure, but it can take up to eight weeks. Kittens under six months of age may test positive after having received antibodies from their mothers, either in utero or via milk. It can take up to six months for these antibodies to go away. Thus, it is a good idea to retest a kitten who tests positive after he or she has reached six months of age. Can FIV be treated? There are no proven treatments to rid a cat of FIV. Most FIV-positive cats handle the disease well, but it is important to concentrate on treating the secondary illnesses. What can be done to prevent the spread of FIV? Cats should be kept indoors so they do not fight with a FIV-positive cat. Depending on where one lives, the rate of FIV-positive cats ranges from 4 to 24 percent. A FIV-positive cat can live with a FIV-negative cat as long as neither cat is a fighter, or the FIV-positive cat has no teeth. (FIV-positive cats commonly have severe dental disease, which often means it is necessary to remove all their teeth.) There is a vaccine for FIV, but Best Friends does not recommend it because the vaccine does not have the best efficacy and, after a cat is vaccinated for FIV, the cat will test positive for the virus. At this point, no test can differentiate whether a cat tests positive for FIV from the vaccine or from having the infection. If a cat escapes and is picked up by local animal control, and then tested, the cat may be killed because he or she tests positive. Can FIV-negative and FIV-positive cats live together? Yes, as long as the cats get along and do not fight. The risk that a FIV-positive cat could spread the virus to a FIV-negative cat can be minimized by having them live in separate rooms until you are confident that they will not fight with each other. Can FIV-positive cats have a good and long life? FIV-positive cats can live normal lives both in quality and duration. They do take special care in terms of monitoring them for signs of infection and they do have a tendency to have bad dental disease. Download FAQs About Feline Immunodeficiency Virus (FIV) (92.2 KB)
Retroviruses are species-specific. This means a feline retrovirus like FIV will only infect cats; a human retrovirus such as HIV will only infect humans. Retroviruses are made up of RNA. In the host, the RNA is transcribed into DNA and incorporated into the DNA of the host’s cells. Retroviruses are fragile, being easily inactivated by ultraviolet light, heat, detergents, and drying. How is FIV transmitted? FIV is NOT transmitted by prolonged close contact, as is the case for FeLV. FIV is shed in the saliva and is usually transmitted by bite wounds. FIV transmission in utero or through the mother’s milk is very rare. It could possibly occur if the queen is infected during pregnancy or while nursing the kittens. Queens infected with FIV prior to the pregnancy usually have noninfected kittens. How common is FIV? FIV is found worldwide in domestic cats, and also infects wild felines including snow leopards, lions, tigers, jaguars, Florida panthers, and bobcats. Although the virus was first isolated in 1987, we know the virus has existed for many years. It is most common in outdoor, free-roaming cats. In the United States, 1-2 percent of apparently healthy cats are infected with FIV. Male cats are at least twice as likely to become infected with FIV as female cats. Free-roaming cats are also more likely to be infected since they too are more susceptible to bite wounds. Unlike FeLV, FIV infection is rare in catteries since few bite wounds would be expected in a cattery situation. How does the virus cause disease? FIV infection in cats has three stages, just like HIV infection in humans. The initial or acute stage of FIV infection is often characterized by fever, swollen lymph nodes, and a susceptibility to skin or intestinal infections. This stage generally occurs 4-6 weeks after being exposed to the virus. The second stage is a latent or subclinical stage in which we see no signs of disease. This stage can last for many years. During this stage, the immune system may slowly be destroyed. When the immunodeficiency becomes severe, the third stage of infection occurs. The third stage is the final or AIDS-like stage, and occurs most commonly in cats 5-12 years of age. (FeLV is seen most often in cats 1-5 years of age.) During this final, clinical stage, the cat’s immune system is not functioning correctly since the virus kills essential cells in the system. Because of this, the cat is very prone to infections. These infections, which are usually chronic, may be bacterial, fungal, or parasitic. Often, they are caused by organisms which normally do not cause severe disease in cats. But since the immune system cannot keep them in check, they multiply rapidly and cause disease. These are called opportunistic infections. We can see chronic upper respiratory tract infections, intestinal infections, and skin/ear diseases. Certain cancers may develop in some cats; researchers are determining how FIV is involved. Other cats may show neurologic signs although FIV generally has less effect on the nervous system of cats when compared to the effect of HIV in humans. Anemia can occur and may be a result of a parasitic infection. Once a cat is in the late stages of disease, life expectancy is 1 year or less. What are the clinical signs of disease? FIV-infected cats may show nonspecific signs such as lethargy, loss of appetite, fever, swollen lymph nodes (lymphadenopathy), and weight loss. The signs of FIV infection and FeLV infection are very similar.
Although FIV-positive cats can live for many years, your veterinarian needs to know if your cat is FIV-infected to provide the best care, e.g., proper vaccinations and often more intensive treatment of infections. Stress and exposure to ill animals should be avoided. FIV-positive cats should be kept indoors both to protect them from exposure to disease and also to prevent them from spreading FIV to other cats. There are many antiviral medications for people with HIV infection, but currently there are none which are routinely and effectively used in FIV-infected cats. The antiviral drug AZT, which is used in human retrovirus infections has had some success in cats, although it can cause toxic side effects. Certain agents that have used to modify the immune response in FeLV-infected cats include staphylococcal protein (SPA), Propionibacterium acnes (ImmunoRegulin), low doses of oral human alpha interferon, and an aloe derivative called Acemannan. Well-controlled clinic trials of these agents have not been performed. Cats with FIV-related disease will need to be treated according to the signs of disease they are showing. Infections which occur as a result of the immunodeficiency should be treated aggressively. FIV-infected cats with cancer can receive chemotherapy, radiation therapy, or immunotherapy. Supportive care such as fluids, good nutrition, and antibiotics for secondary infections are essential. How is FIV infection prevented and controlled? Testing and identifying positive cats is the only means by which FIV infection can be controlled. Although FIV is less transmissible than FeLV, any FIV-positive cat should be separated from non-infected cats. Cats in the terminal stages of the disease can shed large amounts of the virus in their saliva and can pose a greater threat to uninfected cats. Since cats who roam are more likely to sustain cat bites, cats should be kept inside, or supervised when outside and not be allowed to roam. A vaccine against FIV, produced by Fort Dodge, was approved for use in Spring 2002. It does not provide 100% protection, and vaccinated cats will test positive on the antibody test. The American Association of Feline Practitioners does not currently recommend use of the vaccine. Are there human health risks associated with FIV-infected cats? The retroviruses are species-specific. There is no evidence FIV can be transmitted to mammals other than cats. A potential human health risk can occur from exposure to some of the secondary infections FIV-infected cats may acquire, such as toxoplasmosis.