By Jean Hofve, DVM

Feline Immunodeficiency Virus (FIV) is a relatively “new” cat disease; it was first discovered in domestic cats around 1975. Since then it has been found that many big cats (more than 80% of Serengeti lions, for instance) also harbor this virus. In big cats, the disease seems to be benign and rarely causes overt signs.

FIV in domestic cats

In domestic cats, FIV is primarily transmitted by bite wounds. Thus, it commonly affects mainly outdoor cats, and male cats much more frequently than females. It is not uncommon in feral cat colonies, but it does seem to exist in “pockets” rather than being distributed more generally. That is, it may infect several cats in one neighborhood or one colony, but not another one nearby.

Like most viruses, FIV is specific to its host species and infects only cats; it is not contagious to people. FIV is found in 1-1/2 to 3% of all cats in the U.S. The incidence of the disease has not changed significantly over the years. The actual rate of transmission between cats is not really known. It is likely that many cats who are exposed to the disease never become truly infected. In some cases the amount of exposure may not be enough to harm the cat, or the immune system is strong enough to fight it off.

FIV is a relative of the lentivirus (“slow” virus) that causes AIDS. In fact, FIV is often referred to as “Feline AIDS”. Unlike AIDS, however, one pharmaceutical company has produced a vaccine for the disease. Unfortunately, the vaccine has many problems, and may end up killing many more cats than it protects.

The FIV vaccine – helpful or harmful?

There are two basic types of vaccines. Modified live vaccines (MLVs) contain live virus particles that have been altered through various techniques so that it is no longer infectious, but will still reproduce itself in the animal. These vaccines generally produce long-lasting immunity. The feline distemper vaccine is an example of an MLV. The other major type is the killed vaccine. Killed vaccines contain virus particles that have been completely inactivated and cannot reproduce. In order to produce sufficient antibodies, a variety of agents are added to the vaccine to “stimulate” the immune system. These agents are called “adjuvants.” Certain adjuvants have been implicated as causing vaccine-associated fibrosarcoma, a particularly malignant and hard-to-treat type of cancer. Killed vaccines include the rabies and feline leukemia vaccines. Both of these vaccines are known to cause fibrosarcomas. The FIV vaccine is a killed vaccine, means that it, too, is likely to cause tumor formation.

The FIV vaccine is not very effective, and may not protect the cat at all because it only covers a few of the many virus strains that exist. Research suggests that giving the FIV vaccine can actually make the cat sicker!

But the most dangerous problem with the FIV vaccine is that a vaccinated cat will test positive for FIV on all currently available tests, even the most sensitive ones. If a vaccinated cat becomes ill, there is no way of knowing whether or not he actually has active FIV. The vaccine manufacturer (Fort Dodge) admits that this is a problem, but says that, hopefully, in the future, a test may be developed that can distinguish between a vaccinated cat and an infected one. This never happened. For now, if an FIV-vaccinated cat is unfortunate enough to become lost and end up in a shelter that tests for FIV, he will most likely be euthanized. Feline experts do NOT recommend this vaccine.

Is FIV a death sentence?

When FIV was first discovered, veterinarians recommended immediate euthanasia for any cat testing positive. When I volunteered at a local clinic before vet schooll, I remember one of the techs sobbing as the head vet insisted on killing her beautiful young FIV+ cat, to “protect” the other cats in her home. Fortunately, we have learned much more about the disease since then!

Like the Serengeti lions, many FIV+ cats live long lives without ever developing symptoms of the disease. Some of these may have been “false positives”; that is, the FIV blood test was erroneously positive. As many as 30% of positive FIV tests are erroneous. Ideally, all positive results should be confirmed with a more sensitive test. Unfortunately, in the money-conscious shelter environment, the more expensive confirmatory test may not be an option. Kittens may test positive when young because they carry their mother’s antibodies, and these can persist for many months. However, after 6 months of age, a positive test indicates infection.

Most FIV+ cats could be adopted and live with FIV-negative cats with very little risk of transmitting the disease. Because FIV is only transmitted through bite wounds, a non-aggressive FIV+ cat would not put other cats at risk. Sadly, most FIV+ cats in shelters are euthanized, or segregated and “warehoused” for the rest of their lives with little chance of adoption.

Dr. Don Hamilton, veterinarian, homeopath, and author of Homeopathic Care for Cats and Dogs, says, “Of course, it is critical to remember that these viruses are primarily only a problem in immunosuppressed cats. Keeping a cat healthy with good food, and avoidance of stressors, like vaccination, is more important for viruses like FeLV and FIV.” In other words, while these diseases are infectious and present in many environments, most healthy cats who are exposed, will not get sick. Supporting your cat’s general health with proper diet and minimal vaccines are the best preventatives for FIV. Keeping cats indoors, of course, reduces or eliminates the risk of exposure to FIV.

FIV is not a death sentence. However, sensible precautions should be taken. FIV+ cats should be kept strictly indoors to eliminate the risk of transmitting the disease to other cats through fighting, as well as to reduce exposure to secondary infections that could harm the cat.

Helping your FIV+ cat stay healthy

FIV primarily affects the immune system, which results in lowered resistance to infections. Like AIDS, there may be a long latent period where the cat is apparently healthy. Because of their weakened immunity, many FIV+ cats ultimately succumb to secondary viral or bacterial infections that would be relatively harmless in a normal cat.

Because a stressed immune system is more prone to infection, keeping an FIV+ cat’s stress level to a minimum is essential. Cats are territorial; the more cats in a household, the more stress is placed on each individual cat to maintain its position and boundaries. This can lead to aggression as well as stress: not good for anyone! While well-meaning rescuers want to save the maximum number of cats, if there is an FIV+ cat in the picture, it may be wisest to not take in any more cats, and to adopt out those who are eligible.

Extra-special care should be taken to keep the environment (water and food bowls, litter boxes, bedding, toys, etc.) clean so that bacteria and other viruses can’t take advantage of the FIV+ cat’s weaker immune system. Diluted household bleach (about 4 oz of bleach to a gallon of water) is one of the best disinfectants known to man, and will kill virtually all infectious organisms. The FIV virus itself is not hardy, and does not live more than a few hours when exposed to the environment.

In addition to managing the environment, flower essences can be helpful to the FIV+ cat to enable him to cope with his environment and the disease. We recommend Spirit Essences remedies.

It is important to support the immune system with good nutrition (there are several articles on nutrition in our Article Library and Bookstore), antioxidant supplements, probiotics, and other immune-boosting treatments such as homeopathy and acupuncture. However, because the immune defenses of the FIV+ cat may be weak or inadequate, we don’t recommend a raw meat diet as the first step toward improving nutrition. Homemade is great, but because of contamination problems in the meat-packing industry, it’s best to start out using cooked meat and gradually move to raw as the cat’s health improves.

Medical care for your FIV+ cat

Conventional medicine has little to offer FIV+ cats. Interferon appeared promising in early trials but has since proven completely ineffective. Antibiotic therapy can be used for secondary infections, and steroids may be used to combat pain or wasting in order to improve quality of life in severely affected cats.

A major symptom of FIV is severe gingivitis (inflammation of the gum tissue around the teeth), usually attributed to a deep viral or bacterial infection. A fraction of cow’s milk, lactoferrin, may be useful for treating this symptom.

Another common symptom is anemia, or low numbers of red blood cells. This can be treated with drugs that stimulate the bone marrow, but serious side effects are common.

Fever, weight loss, and poor coat condition are common signs, as are chronic or recurrent infections of the respiratory tract, bladder, and skin. It is important for the guardian to watch the FIV+ cat closely and act as soon as any symptoms are noticeable so as to maximize the benefits of treatment.

Many FIV+ cats live normal lives and never show signs of the disease. However, once a cat develops symptoms, the odds are that, in spite of our best care, he will ultimately lose the battle against the disease. Love and supportive care are the best weapons in our arsenal, but even these cannot prevent the disease from running its course. Sadly, it is our responsibility as caretakers to consider what the end should be like. In many cases, these cats will suffer terribly before the disease itself ends the fight, and humane euthanasia is often the best option.

It’s important to determine ahead of time what the criteria will be for this decision. These may include: when the cat is not eating or drinking, or is hiding constantly, taking no interest in surroundings, not responding to affection—any signs that feel appropriate to you may be your signal that enough is enough, and it’s time for a peaceful and loving release. It is ultimately the greatest gift of love you can give.

Do you really know what's in your cat's food?

Signup now and find out! Get our free Pet Food Label Quiz!

I agree to have my personal information transfered to GetResponse ( more information )

You can unsubscribe at any time.