PREVALENCES OF FELINE LEUKEMIA-VIRUS AND FELINE IMMUNODEFICIENCY VIRUS-INFECTIONS IN CATS IN SYDNEY

Objective To determine prevalences of feline leukaemia virus (FeLV) an d feline immunodeficiency virus (FIV) infections in 'healthy' cats tha t, through acute misadventure or other circumstance, were presented to veterinary practitioners. Prevalences of FeLV and FIV in this populat ion were compared to those in a population of predominantly sick cats. Design and procedures Serum specimens were obtained over a 2-year per iod from 200 cats oldeer than 1 year of age presented to veterinary cl inics for routine procedures, including cat fight injuries or abscesse s, vehicular trauma, neutering, dental scaling, vaccination, grooming or boarding. An additional 894 sera were obtained over approximately t he same period from specimens submitted by veterinarians to a private clinical pathology laboratory, mainly from sick cats suspected of havi ng immune dysfunction, but including some sera from healthy cats bring screened prior to FeLV vaccination. FIV antibody and FeLV antigen wer e detected in samples using commercial enzyme immunoassays. Results Am ongst 200 'healthy' cats, the prevalence of FeLV infection was 0 to 2% , and the prevalence of FIV was 6.5 to 7.5%, depending on the stringen cy of the criteria used to define positivity. FIV infection was signif icantly more prevalent in cats which resided in an inner city environm ent (P = 0.013). Of the 894 serum specimens submitted to the laborator y by practitioners, 11/761 (1.4%) were FeLV positive, while 148/711 (2 0.8%) were FIV positive. The prevalence of FIV was significantly highe r in these predominantly 'sick' cats than in cats seen for routine vet erinary procedures (P < 0.00001), while there was no difference in the prevalence of FeLV (P = 0.75) Conclusions The prevalence of FeLV and FIV in healthy cats may have been substantially overestimated in some previous Australian surveys. FeLV infection would appear to be a rare cause of disease in Australian cats. The higher prevalence of FIV posi tivity in sick as opposed to healthy cats infers that FIV infection co ntributes to the development of disease.