Serologic survey of trichinellosis in wild mammals kept in a Mexico City Zoo.
A serologic survey of Trichinella infection was carried out to determine the prevalence of this parasitosis among wild mammals kept in captivity at the Chapultepec Zoo. This was prompted by the necropsy finding of a heavy Trichinella infection in a Canadian polar bear (Ursus maritimus) that had been kept at the Zoo for more than 11 years. The parasites recovered were identified as T. nativa (T2). A serologic study based on ELISA and Western blot analysis was performed in serum samples from two polar bears (U. maritimus), six wolves (Canis lupus); nine foxes (Urocyon cinereoargenteus); seven coyotes (Canis latrans); nine jaguars (Panthera onca); ten lions (Panthera leo); 11 tigers (Panthera tigris); six panthers (Panthera pardus); eight leopards (Panthera pardus); two lynxes (Lynx rufus); five pumas (Felis concolor); one yagouaroundi (Felis yagouaroundi); and one ocelot (Felis pardalis). In these assays, 25% and 27% of the samples studied were positive using total muscle larva extract from T. nativa (T2) or T. spiralis (T1), respectively. When T. spiralis (T1) excretory/secretory products or surface/stichosomal antigens were used, 15 and 13% positivity was obtained respectively. The reactivity rates obtained among the different groups varied from 11 to 83%, wolves having the highest infection rate. Western blot analysis of positive ELISA sera showed an antigenic recognition pattern characteristic of animals infected with Trichinella.