Retrospective and longitudinal study of salmonellosis in captive wildlife in Trinidad

Morbidity and mortality of captive wildlife at the Emperor Valley Zoo, Trin idad from 1993 to 1996 were analysed to determine involvement of Salmonella spp, A 6 mo longitudinal study was conducted to determine the frequency of isolation of Salmonella spp, from apparently healthy; sick and dead wild m ammals. birds, and reptiles. The antibiograms of Salmonella isolates were d etermined using the disc diffusion method. Fecal samples randomly selected from animal enclosures and cloacal swabs of snakes were cultured for Salmon ella spp, following enrichment in tetrathionate and selenite cystine broths . For the 1993-86 period. Salmonella spp. was implicated in 17 (12%) of 141 sick or dead animals and the predominant serotype was S. typhimurium. Duri ng the 6 Ino prospective study in a mean animal population of 1,186, there were 20 (2%) and 14 (1%) animals that were sick and died respectively; Salm onella spp. was implicated in only one mortality. Overall, of 1,012 samples from apparently healthy wildlife cultured, 66 (7%) yielded were S, seigbur g (16 isolates), S, gaminara 24 serotypes of Salmonella. The predominant se rotype samples yielded S. typhimurium. The (6 isolates), and S. thompson (6 isolates). None frequency of isolation of Salmonella spp, in reptiles (14% ) was significantly. higher than found in either mammals (7%) or birds (3%) . Sixty-five (99%) of 66 Salmonella spp, isolates exhibited resistance to o ne or more of the nine antimicrobial agents tested. Resistance was high to cephalothin (92%), moderate to streptomycin (35%) and tetracycline (29%), b ut significantly low to gentamicin (2%), chloramphenicol (0%), and sulphame thoxazole/trimethoprim (0%). The prevalence of asymptomatic infections by S almonella spp, in zoo animals was high and the very high prevalence of anti microbial resistance could be a problem when treating salmonellosis.