The infectious retroviruses feline leukemia virus (FeLV) and feline immunodeficiency virus (FIV) may affect any organ in cats; both can lead to lymphoma, blood dyscrasias, ocular disease, and secondary and opportunistic infections. Guidelines for prevention and management of FeLV and FIV have been published by the American Association of Feline Practitioners (AAFP) and the European Advisory Board on Cat Diseases. Until recently, most of the seroprevalence data for these two viruses in North America have come from the US. Survey data from Canada show that the seroprevalence for both FeLV and FIV infection in Canada appears higher than that reported for the US. In a 2006 study, 18,038 cats were tested in North America, including 325 cats from Canada.1 The seroprevalence of FeLV was 2.3% and the seroprevalence of FIV was 2.5%. Coinfection existed in 0.3% of cats.

The current study summarizes data from various surveys in Canadian provinces from 1989 to 2010. The highest reported seroprevalence of FIV was reported in 2005 in Ottawa as 23% among urban strays and 5.9% in owned cats. A 2009 survey among all provinces reported a seroprevalence of 4.3% for FIV and 3.4% for FeLV.

Testing and isolation of infected cats are important for disease control. Further research into geographic variations in retrovirus seroprevalence is warranted. Screening ELISA testing is readily available; however, independent evaluation of newer test methods (eg, PCR) is not widely available.

Commentary: Testing for and knowing the retrovirus status of all cats are recommended by the AAFP, which also recommends that all cats be tested for FeLV and FIV at appropriate intervals based on individual risk assessment. The AAFP also highly recommends that all kittens be vaccinated against FeLV. Cats with lifestyles that put them at risk should also be vaccinated for FIV. The most current AAFP guidelines can be found at catvets.com. Recommendations from the European Advisory Board on Cat Diseases can be found at abcd-vet.org.—Patricia Thomblison, DVM, MS

Feline leukemia virus and feline immunodeficiency virus in Canada: Recommendations for testing and management. Little S, Bienzle D, Carioto L, et al. CAN VET J 52:849-855, 2011.

1. Seroprevalence of feline leukemia virus and feline immunodeficiency virus infection among cats in North America and risk factors for seropositivity. Levy JK, Scott HM, Lachtara JL, Crawford PC. JAVMA 228:371-376, 2006.