FIV and FeLV are incurable viruses that only affect cats. Humans cannot catch or transmit these viruses. Not all cats that become infected will develop the disease.
Cats who test positive for FIV often live long, healthy lives. Many veterinary spay and neuter clinics do not test for FeLV or FIV, because most community cats enjoy excellent health and are no more likely to be infected with disease than owned cats. In fact, owned cats and community cats contract FeLV and FIV at an equally low rate (about 4%)*.
The San Francisco SPCA Community Cats Program does not promote the testing community cats for FIV and FeLV for multiple reasons:
- The percentage of community cats infected with either FeLV or FIV is low. Studies detected FeLV in 4.3% of cats; FIV in 3.5%. This is similar to the rate in owned cats. Several large-scale spay and neuter clinics in the U.S. report only a 1-2% incidence of FeLV in the early years when every cat is tested*.
- Test results can be unreliable and can result in false positives. Cats testing positive should be re-tested at least 28 days after the cat’s last possible exposure to the virus.
- Spaying or neutering cats inhibits the spread of the viruses. Since spaying and neutering reduces or eliminates the primary modes of transmission, such as fighting and breeding, infected cats pose less risk to other cats.
- Infected cats are often asymptomatic and can remain healthy with no sign of illness for many years or for their entire life; considering all factors, more cats likely die from having positive test results than die from FIV-related disease.
- Testing can be prohibitively expensive for a TNR program. The cost of testing (and often re-testing because of false positive test results) could possibly hinder the success of a spay and neuter program. Resources are best applied to spaying and neutering more cats. Increasing the number of cats who are spayed or neutered decreases the incidence of virus transmission.
- FIV tests do not differentiate between FIV infection and FIV vaccination. A positive test could result in euthanizing vaccinated cats who are not infected.
The San Francisco SPCA does not support the euthanasia of healthy cats who test positive for FeLV and FIV. The American Association of Feline Practitioners agrees, recommending against routine euthanasia of healthy FeLV- and FIV-positive cats. Cats showing signs of illness or injury should be trapped and taken to a veterinarian for medical treatment.