Prevalence of feline immunodeficiency virus and Toxoplasma gondii in feral cats on St. Kitts, West Indies.
Toxoplasma gondii (T. gondii) is a cosmopolitan protozoan parasite that infects all warm-blooded species including humans. The definitive hosts of T. gondii are felid vertebrates including the domestic cat. Domestic cats shed oocysts for approximately two weeks in their feces after the primary infection. It has been shown that feline immunodeficiency virus (FIV) positive cats have a higher prevalence of and a higher titer of antibodies to T. gondii than those of FIV-negative cats. The main purposes of this study were to determine FIV prevalence and to investigate the oocysts shedding in FIV-positive and FIV-negative feral cats on St. Kitts. Fecal samples were collected from feral cats while their FIV statues were determined using a commercial SNAP kit. Total fecal DNA of each cat was tested for the presence of T. gondii DNA using a polymerase chain reaction (PCR) consistently detecting one genome equivalent. A FIV-positive status was detected in 18 of 105 (17.1%, 95% confidence interval (CI): 9.9%-24.3%) feral cats sampled. Furthermore, males were three times more likely to be FIV positive than females (p=0.017) with an odds ratio of 3.93 (95% CI: 1.20-12.89). Adults were found to have at least twice the prevalence of FIV compared to cats younger than one year of age (p=0.056) with an odds ratio of 3.07 (95% CI: 0.94-10.00). Toxoplasma gondii DNA was not detected in the feces of any of the 18 FIV-positive (95% CI: 0%-0.18%) and 87 FIV-negative cats (95% CI: 0%-0.04%). A follow-up study with a much bigger sample size is needed to prove or disprove the hypothesis that FIV-positive cats have a higher prevalence of shedding T. gondii oocysts than FIV-negative cats.