FIV in Cats

Dr. Jason Gagné, DVM, DACVIM
By Dr. Jason Gagné, DVM, DACVIM
Updated: 5/20/20242-4 minutes
Woman with a cat

Feline immunodeficiency virus (FIV) is a major viral infection in cats. Although it is similar to HIV (AIDS) in people, FIV is species-specific, which means it can only be transmitted from cat to cat, not to humans or other animals. This is why it can also be known as “Feline AIDS.”

What is FIV?

FIV is a lentivirus. Lentiviruses typically only cause disease slowly and thus infected cats may remain healthy for many years before showing signs of disease. Once a cat has been infected with FIV, the infection is usually permanent and needs to be managed rather than cured.

How Can My Cat Contract FIV?

FIV is present in the blood and saliva of infected cats, but as it cannot survive for long outside the body and requires a high dose to cause an infection, it is not easily transmitted from cat to cat.

FIV is most commonly spread through a bite from another cat; the virus in the saliva of an infected feline is introduced directly into the blood of the cat it bites. For this reason, male cats that fight often are most likely to be infected.

The virus cannot be transmitted via food, feeding bowls, bedding or hands, so it’s unlikely that cats in a household would spread it to each other (provided they don’t fight).

Occasionally, infection is transmitted from an infected mother cat to her kittens during the birthing process or via her milk.

Sexual contact is not a major means of spreading FIV in cats.

How Does FIV Cause Cat Diseases?

Many FIV-infected cats are able to live happily with the virus for a long period of time, and in some cats FIV will never cause any clinical disease.

FIV in cats infects cells of the immune system (white blood cells), affecting their normal function.

This means that as the disease progresses, germs found in the everyday environment (where they usually do not affect healthy animals) can cause severe illness in cats with a weakened immune system caused by FIV. These secondary infections are responsible for many of the cat diseases associated with FIV.

FIV Symptoms

Although there are no specific symptoms associated with FIV in cats, signs may include:

  • Weight loss
  • Lethargy
  • Fever
  • Gingivitis and stomatitis (inflammation of the gums and mouth)
  • Enlarged lymph nodes
  • Chronic or recurrent intestinal, respiratory, ocular or skin disease
  • Neurological disease (in some cats the virus can affect the brain)

What Treatments Are Available for FIV?

The main goal when managing an FIV-positive cat is to prevent the spread of infection to other cats. It’s also important to maintain a good quality of life for the infected cat.

FIV positive cats should be neutered and kept indoors to reduce the risk of fighting and spreading infection.

Maintaining good health by vaccinating and using regular flea and worm control, in addition to feeding your cat a high-quality diet, is also crucial. Avoiding raw food helps reduce the exposure to pathogens which may be harmful to the cat.

Some antiviral medications used in human patients with HIV infection (such as interferons and AZT) have been shown to help some cats with FIV infection but these can be expensive. It’s important to only give medicine to cats that has been prescribed by your veterinarian.

It can be upsetting to receive a positive FIV diagnosis for your cat, but with good preventative healthcare and support from your veterinarian, most cats with FIV can live happy and healthy lives for many years.

Want more feline health tips? Check out our cat health articles for advice from our experts.

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