What Do I Need to Know About FIV in Cats
Medically Reviewed by Dr. Sarah Jenkins, DVM, Feline Internal Medicine Specialist
Understanding FIV
Feline Immunodeficiency Virus (FIV) is a lentivirus that affects cats worldwide. Often called “cat AIDS” due to its similarity to human HIV, FIV weakens a cat’s immune system over time, making them more susceptible to infections and certain cancers. Despite this serious diagnosis, many FIV-positive cats live long, healthy, and happy lives with proper care and management.
Understanding FIV helps cat owners make informed decisions about care and reduce unnecessary fear surrounding the diagnosis. It’s important to note that FIV is species-specific—it cannot be transmitted to humans or other non-feline pets.
How FIV Spreads
FIV is primarily transmitted through deep bite wounds, which is why outdoor male cats who fight are at higher risk. Casual contact like sharing food bowls, grooming, or touching does not efficiently spread the virus. The virus is present in saliva but at much lower concentrations than in blood.
Other transmission routes include from an infected mother to her kittens during birth or nursing (though this is less common), and through blood transfusions from infected donors (which is why blood for transfusions should always be screened).
The Phases of FIV Infection
Acute Phase
Shortly after infection, some cats may show mild symptoms such as fever, lethargy, and swollen lymph nodes. However, many cats show no symptoms at all during this phase, which can last a few weeks to several months.
Asymptomatic Phase
Following the acute phase, cats enter a long period where the virus is present but they appear healthy. This phase can last for years, during which cats may show no signs of illness whatsoever.
Progressive Phase
Over time, the virus weakens the immune system, and cats become more susceptible to secondary infections. Symptoms may begin to appear as the immune system deteriorates.
Common Health Issues in FIV-Positive Cats
FIV affects the immune system, so cats may experience recurring or persistent infections including dental disease, respiratory infections, skin problems, and urinary tract infections. Other potential issues include chronic diarrhea, weight loss, cancer (particularly lymphoma), neurological problems, and anemia.
Diagnosis and Testing
FIV is diagnosed through blood tests that detect antibodies to the virus. The most common test is the ELISA (enzyme-linked immunosorbent assay), which can be performed in most veterinary clinics. Positive results may be confirmed with additional tests such as Western blot or IFA (immunofluorescence assay).
Kittens under six months may test positive due to maternal antibodies and should be retested after six months of age. Cats who have been vaccinated against FIV will test positive on standard tests, which is why keeping records of vaccination is important.
Living with an FIV-Positive Cat
With proper care, FIV-positive cats can live many years. Key aspects of management include keeping cats indoors to prevent exposure to other infections and to protect other cats, providing a nutritious diet, regular veterinary check-ups, prompt treatment of any infections, maintaining good dental hygiene, and monitoring weight and appetite.
Most veterinarians recommend feeding FIV-positive cats high-quality commercial food, though some debate exists about raw food diets due to potential bacterial risks.
FIV and Other Cats
If you have multiple cats, the risk of transmission through casual contact is low. However, the risk increases if cats fight. Most veterinary organizations do not recommend isolating FIV-positive cats from other household cats if they get along well and do not fight. However, some owners choose separation as an extra precaution.
Prevention
The best prevention is keeping cats indoors and away from potential fighters. A vaccine for FIV exists but is not considered core and does not provide complete protection. The vaccine may also cause cats to test positive on standard tests. Discuss the pros and cons of vaccination with your veterinarian.
What FIV Does Not Mean
An FIV diagnosis does not mean your cat is dying. Many FIV-positive cats live normal lifespans and die from unrelated causes. It also does not mean your cat will immediately become ill—the progression to illness often takes years, if it occurs at all. With good care and monitoring, most FIV-positive cats enjoy excellent quality of life.
Disclaimer: This article is for informational purposes only and does not constitute professional veterinary advice. If you have questions about FIV testing, prevention, or caring for an FIV-positive cat, please consult a qualified veterinarian for personalized guidance.