Adopting a FIV Positive Cat

Is it safe to add a Feline Immunodeficiency Virus (FIV) positive cat to your home?

In an effort to improve the lives of special needs cats living in shelters and rescue organizations, many cat lovers consider adopting a cat that has tested positive for FIV. But does bringing a FIV+ cat home put other pets and family members at risk?

FIV Vaccine Myths

There is a vaccine available that can help prevent FIV infection, but it is very controversial among feline practitioners. The vaccine typically involves an initial vaccine, and then boosters administered approximately 3 weeks apart and yearly, if the risk for exposure remains. It isn’t the most effective vaccine, and FIV isn’t a real risk for most indoor cats, so vets tend to avoid discussing it with cat parents.

As with other vaccines, the FIV vaccine causes the body to produce antibodies (cells that can recognize FIV and protect the body from infection). However, current FIV tests cannot tell the difference between FIV antibodies obtained through vaccination and those obtained through natural exposure to the disease. This means that once a cat is vaccinated against FIV, there is no reliable way to tell if the cat is FIV (+) or merely FIV-vaccinated. This becomes a huge concern if a roaming cat is picked up by a shelter and subsequently tested for FIV, which is a common practice at shelters. Some shelters automatically euthanize FIV (+) cats that are picked up.

You can see the issue here, not to mention the medical concern of not knowing if your cats have contracted FIV if they become sick.

The other concern is that the vaccine is marginally efficacious at best, even when it does help. There are different strains of the virus, and the vaccine doesn’t protect against them all.
If you are interested in the vaccine, you should first find out what strain the FIV+ cat has to see if the vaccine is even mildly protective against it. Otherwise, you may wrongly believe you are protecting your cats against the FIV virus.

Finally, the vaccine is adjuvanted and adjuvants cause chronic inflammation at the injection site, which can lead to vaccine-associated sarcoma formation, a type of aggressive cancer.

The Truth About FIV Transmission

FIV is generally transmitted to a cat through direct contact with saliva from an infected cat. Most cats are exposed through bite wounds sustained during fights with FIV-infected cats.

While FIV isn’t very easily transmitted among cats, this doesn’t mean that unsupervised cohabitation is recommended. Keeping FIV positive cats separate from FIV negative cats is the only way to safely have them share a home and prevent transmission.

Keeping different water bowls, food bowls, and litter boxes should help with territorial aggression. Feliway diffusers (a feline pheromone) are often helpful for reducing cats’ anxiety levels, but they are not a guarantee for household peace. Some cats become more prone to aggression as they age so this is also something to consider.

The Verdict on FIV

While the number of FIV+ cats euthanized in shelters is heartbreaking, adopting a cat with FIV is not something many vets will endorse. Ultimately, the choice is yours and it can be done with cautious separation, but you should be fully aware of the risks.

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