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Feline Immunodeficiency Virus: Everything You Need to Know 

cat at vet

Feline immunodeficiency virus (FIV) is a relatively rare but serious immune disease specific to cats. It is similar to human immunodeficiency virus (HIV) in people, and you may hear it referred to as feline HIV. The disorder was first identified in the 1980s. While FIV in cats is quite serious, it is fortunately not that common.   

There is no cure for FIV. That being said, there are ways to improve the quality of your cat’s life if they are diagnosed with FIV. Be sure to read our Cat Health Guide for more information about general wellness tips and consult your veterinarian for FIV diagnosis and treatment. 

What is feline immunodeficiency virus? 

FIV is a serious illness that attacks a cat’s immune system. The disease operates by weakening certain white blood cells in your cat’s body. Once FIV has damaged or killed these disease-fighting cells, it is much harder for your pet to fight off common bacteria, viruses and other illnesses.  

Due to their weakened immune system, FIV cats can become extremely ill and even die from common illnesses that typically don’t prove life-threatening for other cats. A simple bacterial infection or foodborne illness may become a fatal disorder in a cat with FIV.  

Most cats with FIV don’t die from FIV itself, but rather from a secondary infection or disease. For this reason, keeping your cat up to date on their preventive care—including any pet vaccines that your veterinarian recommends—is especially important if they have FIV.  

What are the symptoms of FIV? 

Cat FIV infections are not immediately identifiable in most felines. This period of asymptomatic disease is called viral dormancy. It may be months—or even years—before you notice anything is wrong with your cat.  

Once FIV in cats develops into the progressive immuno-compromised stage, symptoms will become more apparent. Typical feline immunodeficiency virus symptoms include: 

  • Inflammation of the gums  
  • Weight loss 
  • Decreased appetite 
  • Swollen lymph nodes 
  • Lethargy 
  • Recurrent fever 
  • Chronic respiratory and/or intestinal disease 

It’s worth noting that the symptoms of FIV can often be explained by other, less serious illnesses. Talk to your cat’s veterinarian about testing before assuming your pet has this serious illness.  

How is FIV diagnosed? 

Veterinarians use blood tests to diagnose FIV. The disease can be identified by a blood test within 2-6 months after exposure. Your veterinarian will take a sample of your pet’s blood and use a test to look for antibodies to the disease. If the antibodies are spotted, your cat will test positive for FIV. One of the most common tests that can be run in the vet clinic is the enzyme-linked immunosorbent assay—often called ELISA. A positive ELISA test should be confirmed by another type of test run at a lab.  

It is recommended that kittens be tested for FIV at least twice in their first year of life, with at least one of those tests being done between 6 and 12 months of age. Accuracy of testing for FIV in kittens improves after 6 months of age. Adult cats that go outdoors or are around cats with an unknown exposure status should be tested at least once a year.

If your cat’s white cell count gets low enough, a vet may diagnose them with feline AIDS—the acquired immunodeficiency syndrome of cats. Your veterinarian may also consider your cat to have advanced to this stage of diagnosis if the collection of their symptoms becomes chronic and serious. However, many cats with FIV never deteriorate to the point of having feline AIDS. 

How contagious is FIV in cats? 

FIV is not as contagious as many other diseases—casual contact is unlikely to lead to transmission. If a cat shares a water bowl or sleeps near another cat who is positive for FIV, they are unlikely to contract FIV.  However, once a cat has been diagnosed with FIV it is recommended to keep them inside away from other cats, just to be safe.

FIV is primarily spread via bite wounds—it is not an airborne disease. The most common way an FIV cat will spread the disease is through fighting with another cat. The disease may also be spread from a mother to her young, and kittens born to an FIV-positive mother may test positive.  

Unfortunately, there is no effective vaccine for cats to help them avoid FIV infection.  

Do FIV cats need special care? 

Yes, pets in the mid to later cat FIV stages will likely need some additional care. There is no cure for this disorder, but you may be able to keep your pet alive for many years. The following are the most important care tips for cats with FIV: 

  • Don’t feed your pet raw meat or unpasteurized food that puts them at risk for foodborne illnesses  
  • Offer a well-balanced and nutrient-rich cat food diet to improve their overall health 
  • Keep your pet away from other animals who may transmit the infection to your cat  
  • Treat any symptoms of a secondary infection quickly to give your cat the best chance of recovery  
  • Keep your pet isolated from other cats whenever possible—especially if they are known fighters—to avoid transmission  
  • Bring your cat to the vet at least every six months for a wellness check; FIV in cats may require more frequent exams as your pet’s condition changes  
  • Consider being open to new therapies. While AZT treatment and other antivirals are not shown to prolong life in cats with FIV, ongoing research may mean more options in the future  

What is the life expectancy of a cat with FIV? 

Most otherwise healthy cats will go on to live an average life span after they are diagnosed with feline immunodeficiency virus. Though 18% of cats with FIV die within five years, most others will survive to enjoy a typical life expectancy. The best thing you can do to prolong the life of a cat with FIV is to keep them from getting a serious secondary infection and quickly treat any problems that do develop.  

Can cats heal from FIV? 

There are currently no treatments that cure FIV, and there are no cat vaccinations available that can prevent it. By keeping your cat indoors, away from other cats and on a healthy diet, you can often prevent your pet from developing a deadly secondary infection. Your cat will never fully recover from FIV, but they can still enjoy a high quality of life.  

Reviewed by Dr. Whitney Miller, DVM, MBA, DACVPM

As Petco’s Chief Veterinarian, Dr. Miller is the lead veterinary subject matter expert, overseeing the company’s standards of excellence in animal care and welfare, growth in pet services and much more. Dr. Miller leads Petco’s medical team, supporting over 200 full-service hospitals and mobile vaccination clinics operating in over 1,000 Petco Pet Care Centers nationwide

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