Cats and FIV: Symptoms, Causes, and Treatments


In this Article

  • What Are the Symptoms of Cat FIV?
  • How Is Cat FIV Transmitted?
  • How Do You Diagnose Cat FIV?
  • What Are the Treatments for Cat FIV?

Feline immunodeficiency virus, or cat FIV, is a retrovirus infection first discovered in cats in the U.S. The virus is often referred to as cat HIV or cat AIDS because it has a similar effect on felines. FIV-positive cats may have the virus in their system for years before showing signs of illness. 

The virus works by killing or damaging cells in a cat’s immune system, often targeting white blood cells. The ongoing damage of FIV in cats eventually leads to a weakening of the immune system. Once that happens, cats with FIV can become vulnerable to secondary infections.

People often think that FIV and the feline leukemia virus are the same illnesses because they can cause similar symptoms in cats. While both derive from the retrovirus family, they are different diseases. 

What Are the Symptoms of Cat FIV?

Because the cat FIV virus can move slowly in a cat’s system, your cat may go on for years without exhibiting any noticeable symptoms. Once a cat starts showing signs of illness, the disease can cause bouts of illness followed by long periods of apparent good health. 

It is a good idea to take your cat in for a vet exam if they start showing any of the following FIV symptoms:  

  • Poor coat condition
  • Fever that keeps coming back
  • Lack of appetite
  • Inflammation in the mouth and gums
  • Chronic or recurrent infections in the eyes, skin, upper respiratory tract, or bladder
  • Constant diarrhea
  • Persistent eye problems
  • Seizures
  • Behavioral changes
  • Signs of neurological disorders  

Symptoms of FIV in cats can also include slow and steady weight loss. Many felines infected with the illness end up developing some form of cancer or blood disease. 

How Is Cat FIV Transmitted?

Most cases of cat FIV come through an infected cat passing it to another through a deep bite. That makes outdoor cats especially vulnerable as they may end up in a territorial dispute that leads to such an injury. A mother cat infected with the cat FIV virus can pass it to her kittens. While FIV is contagious, cats typically do not transmit the virus by sharing an eating bowl with other cats or through other feline contact actions like:  

  • Social grooming
  • Sneezing
  • Sharing a litter box   

A cat can’t transmit the FIV virus to a human. They can only pass FIV on to another cat. You can help prevent your cat from contracting the virus by:  

  • Keep them indoors to avoid potential contact with infected cats.
  • Put a leash on your cat when you walk them outside.
  • Verify that any cats that will be around your pet for prolonged periods have tested negative for FIV.
  • Make sure recently adopted cats get tested for FIV.
  • While FIV vaccination is not usually advised, you can discuss with your veterinarian.  

FIV infections are most common among middle-aged cats between 5 and 10 years of age. Male cats are twice as likely as females to become infected with FIV.

How Do You Diagnose Cat FIV?

If you start seeing potential signs of the FIV cat virus in your pet, you should have them examined by a veterinarian. It is a good idea to make a note of the cat FIV symptoms you’ve observed and pass that on to the doctor. It would also help if you keep your cat from going outside until you receive a confirmation on whether they have FIV. That way, you can prevent your pet from potentially spreading the virus to other cats. 

Vets typically diagnose FIV in cats by performing blood tests that look for specific antibodies present in an infected cat’s blood. Your doctor may opt for additional testing before settling on a diagnosis of FIV. It is especially important to have pregnant cats evaluated for the virus because they can pass FIV to their kittens. 

What Are the Treatments for Cat FIV?

There is no antiviral remedy available specifically for the treatment of FIV in cats. Most vets put their focus on trying to keep a cat asymptomatic for an extended period. One study found that FIV-positive cats live for an average of 5 years after their diagnosis, but their prognosis can vary greatly.

If FIV symptoms start to show up, they treat any secondary illnesses that result from the virus. Treatments often recommended to help cats with FIV include:  

  • Medications to help with any secondary infections
  • Fluid and electrolyte replacement therapy
  • Parasite control
  • Drugs to boost the immune system
  • Drugs that help with inflammation
  • A nutritional diet that is easy on the cat’s system  

Your vet may also recommend the following tips for caring for FIV-positive cats:  

  • Keep the cat indoors to protect their immune system and prevent them from infecting other cats.
  • Neuter male cats to prevent territorial behavior.
  • Spay female cats to prevent FIV from being passed to future offspring.
  • Watch for any changes in the cat’s behavior or health.
  • Take the cat in at least two times per year for a vet checkup that includes a urinalysis and blood count.
  • Eliminate raw foods and eggs from their diet.  

Antiviral therapies like interferons or antiviral drugs like AZT (azidothymidine) can help extend the periods when your cat does not have symptoms. Early treatment of FIV can extend an FIV-infected cat’s life expectancy and allow them to have a fairly good quality of life.

Show Sources


ASPCA: “Common Cat Diseases.”

Cornell University College of Veterinary Medicine: “Feline Immunodeficiency Virus.” 

International Cat Care: “Feline Immunodeficiency Virus (FIV).”

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