Epidemiology of Salmonella Species in Diarrheic Sheep and Goats

Abstract

A cross sectional survey study aimed to: 1) Identify the management factors associated with the occurrence of salmonellosis in some diarrheic sheep and goats belonging to mixed reared flocks in Giza governorate, Egypt, 2) Investigate the presence of enterotoxin (stn) gene in the recovered Salmonella spp. strains, and 3) Build a phylogenetic tree for the partial codon sequence of stn gene of some recovered strains in order to provide a scientific basis for the implementation of practical preventive measures. A total number of 518 diarrheic sheep and goats belonging to 7 mixed flocks of sheep and goats were enrolled and from which rectal swabs were collected and subjected to culture for Salmonella spp. Enterotoxin (stn) gene was detected using polymerase chain reaction assay (PCR), and the PCR amplicons of nine randomly selected strains were purified, sequenced and deposited in the GenBank. The obtained data about disease occurrence were statistically analyzed using Chi-square test in order to identify disease-associated factors. The overall prevalence of salmonellosis among diarrheic sheep and goats was 3.86%, and the disease prevalence per each flock ranged from 0% to 7.55%. The factors that were found to be associated with disease occurrence included, absence of isolation of newly- purchased animals and isolation pen for sick animals, over the counter use of antimicrobials, lack of disinfection of feeding utensils and water troughs, and presence of rodents in feed storage area. Enterotoxin (stn) gene was detected in all recovered salmonellae, and the phylogenic analysis of stn gene of the selected strains and the retrieved sequences from GenBank showed the relatedness of the isolated strains to the other strains isolated from different sources. Accordingly, the analysis of disease associated factors and the robust phylogeny findings provide valuable data that will be useful for implementation of preventive measures for salmonellosis in small ruminants.