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What Is FIV in Cats? An Overview for Cat Owners

fluffy cat with yellow eyes and stripes

Like humans, cats are susceptible to a variety of infectious diseases. FIV is just one of the diseases your cat may encounter throughout its life, although it can also be easily prevented. 

What is FIV in cats? How is it transmitted? Are there factors that put your cat more at risk for contracting it, and what symptoms should you be on the lookout for? 

We’ve got an overview of FIV that every pet parent should be familiar with (especially if you don’t have strictly indoor cats).

What Is FIV in Cats?

FIV is short for feline immunodeficiency virus, and it is one of the most common infectious diseases of cats globally. We’ve known about FIV in cats since the mid-1980s, and researchers estimate that up to five percent of the feline population will show evidence of exposure. 

FIV is a retrovirus, meaning it uses RNA to “sneak” its blueprint into a cat’s DNA and then tricks the body into replicating it like other genetic material. The virus works similarly to HIV (human immunodeficiency virus), weakening the immune system and leaving the host susceptible to secondary infections. 

Like HIV, FIV can remain dormant in the system for years and may never cause problems. However, it can also progress quickly and wreak havoc in multiple body systems. 

While FIV is similar to HIV, it can not be transmitted from cats to humans. There are also multiple strains (or subtypes) of FIV, some of which have been  shown to be more harmful than others. However, these subtypes aren’t usually specifically tested for as treatment and management remain the same.

How Is FIV Transmitted?

Cats can become infected with FIV in a few different ways. The primary mode of transmission is through contact with infected saliva, where the FIV virus is shed. 

However, FIV is rarely transmitted by casual contact, and cats are more likely to become infected after being bitten (as the saliva allows the virus to enter the body through the open bite wound).

Less frequently, cats can become infected through sexual transmission or after being born to an infected mother cat (via the placenta or through nursing). 

Because of its specific mode of transmission, cats that are the most likely to be infected with FIV include:

  • Outdoor cats
  • Male cats (especially those who are unneutered)
  • Cats with a history of cat bite abscesses 

Spaying and neutering, as well as keeping your cats indoors, can be an effective way to reduce your cat’s exposure potential. Plus, outdoor cats have a significantly lower lifespan than indoor cats, so restricting their ability to go outdoors unaccompanied can also expand their lifespan (and reduce your anxiety level).

It’s also important to note that there is a vaccine available against FIV, which is part of most feline wellness visits. While the FIV vaccine doesn’t protect cats 100 percent, it remains the most effective way to prevent FIV. 

What Are the Symptoms of FIV?

There are three phases to FIV infection — acute, latent (asymptomatic), and progressive. 

The acute phase, which occurs one to three months after the initial infection, is often very mild and attributed to other causes unless you know your cat has been exposed. Symptoms are usually limited to swollen lymph nodes and low-grade fever; even the most vigilant pet parent may miss them if they don’t know what they’re looking for. 

After that, cats can remain asymptomatic for years; some may never exhibit signs of exposure at all and live completely normal, happy lives. The virus is still present, though, and often continues to slowly replicate in the system. Even asymptomatic cats can show blood work abnormalities, like decreased white blood cells or an increased protein level. 

For those who enter the progressive phase of FIV, signs of illness don’t come from the disease itself but from secondary infections they have picked up due to their vulnerable immune system. 

FIV-infected cats in the progressive phase are also at an increased risk of developing certain cancers. The progressive phase is also known as the terminal phase because the survival rate significantly decreases. The goal of FIV treatment and management is to avoid this phase. 

Upset Stomach

FIV often makes cats more susceptible to gastrointestinal issues like vomiting and diarrhea. Because these issues can quickly become chronic, cats with FIV infection may also begin to experience weight loss. 

Upset stomachs can be difficult to recognize in cats, especially if you’re not regularly checking their litter box. Cats who vomit without an obvious trigger (like eating too fast or a food indiscretion), may lick their lips or “hard” swallow frequently or have bowel accidents should be seen by a veterinarian. 

However, it isn’t just an upset stomach that may make an FIV-positive cat lose weight. FIV can also make cats more vulnerable to oral issues, including gingivitis (inflammation of the gums) and stomatitis (inflammation of the mouth). These conditions can make it painful for your cat to eat, leading to weight loss.

Runny Nose

Many cats with FIV will develop a runny nose or congestion, a condition known as rhinitis. Nasal discharge is often watery and clear but can become thicker and turn green or yellow if an infection is present. 

Sneezing is also common, although often unproductive. Some cats may also paw at their face.

Rhinitis is another symptom of FIV that can look like many other common feline health issues, like allergies. However, if your cat’s runny or stuffy nose becomes chronic, it requires a trip to the veterinarian to discuss it further. 

Irritated Eyes

Chronic conjunctivitis (recurrent infection of the thin membrane around the eyes) can be another sign that your cat is dealing with an FIV infection. Symptoms like squinting (of one or both eyes), abnormal discharge, and third eyelid visibility are frequently seen. 

However, conjunctivitis is something that most cats will develop at some point in their lives, so it can be easily missed as a red flag for FIV unless you’re aware of potential exposure.  

How Is FIV Treated?

There is no cure for FIV. However, plenty of FIV-positive cats continue to have a high quality of life and no impact on their lifespan. The key is getting a proper diagnosis and staying vigilant for any signs of secondary issues. 

Cats with FIV do best with frequent vet visits, a healthy diet (avoiding raw foods), and a focus on wellness-related preventives like parasite control and routine vaccinations.

Diagnosis starts with a visit to your veterinarian’s office and a “spot” test using an ELISA (enzyme-linked immunosorbent assay) technique. ELISA blood tests check for the presence of antibodies to FIV, which are produced by the immune system after the infection has occurred. 

Your veterinarian may also check for other infections that can mimic FIV, including feline leukemia virus (FeLV) and feline herpesvirus (FHV). Routine blood work is also a normal part of FIV work-up, as it closely looks at white blood cells, liver and kidney function, iron storage, etc. 

Once a cat has been diagnosed with FIV, management becomes monitoring for secondary infections and treating them quickly when they do occur. In many cases, this means antibiotics, which only temporarily treat the issue. Some veterinarians have had success with human anti-HIV medications (like AZT), but research is still ongoing into their effectiveness.

Keeping your cat’s stress level low can also help with FIV management. Stress (especially chronic stress) can lower your cat’s immune system even further, making them even more susceptible to secondary issues. 

Finding ways to reduce stress, like making environmental changes or using feline-specific CBD products, can help keep their immune system strong so they can more effectively fight off infection.

Signs of stress in cats can be as simple as your cat hiding. Some cats even experience separation anxiety, the same as dogs. Knowing what’s normal for your cat gives you a jumpstart on more quickly identifying issues and working to find a solution. 

Like us, stress can come from anywhere and is often specific to your cat’s personality and environment — there are no one-size-fits-all triggers.

In addition, FIV-infected cats should be kept indoors. Not only does going outside increase their likelihood of developing secondary infections, but it also increases the likelihood that they’ll expose another cat to FIV. 

FIV-positive cats do best when they’re the only cat in the household. If you have other cats that are not positive for FIV, they should be kept separate (this includes food and water bowls and litter boxes). While casual contact (like grooming) only rarely leads to FIV infection, that’s a risk that you’ll need to decide on your own and discuss with your veterinarian.

The Bottom Line

What is FIV in cats? Although this immunosuppressive virus is one of the most common feline infections worldwide, you can also prevent it with a simple vaccine. 

However, many FIV-positive cats still go on to lead normal, healthy lives. The key is staying vigilant for any signs of secondary infections, reducing their stress level, and following your veterinarian’s recommendations.  


Feline Immunodeficiency Virus (FIV) | Cornell University College of Veterinary Medicine 

Conjunctivitis | Cornell University College of Veterinary Medicine 

Rhinitis and Sinusitis in Cats – Cat Owners | Merck Veterinary Manual