Prevalence and carcass contamination with Campylobacter in sheep sent for slaughter in Scotland

Campylobacter species have been identified as the major cause of acute bacterial enteritis in the U.K. It has been suggested that the role of sheep in the epidemiology of Campylobacter has been underestimated. The aim of the present study was to determine the prevalence of Campylobacter in sheep sent for slaughter into an abattoir in Scotland and the prevalence of Campylobacter on the carcasses as a potential risk for human campylobacteriosis. Fecal samples and swabs (from fleeces and carcasses) were collected and processed using standard laboratory methods. The prevalence of Campylobacter obtained was unexpectedly high (49% positives from fecal samples by direct plating; 64% from fecal samples after enrichment; 95% from the fleeces after enrichment and 90% from the carcasses after enrichment) in comparison with the prevalence reported in the literature. It is the first time that such higher prevalence have been reported for Campylobacter isolated from sheep. The results showed that Campylobacter jejuni accounted for 75% of all the positive samples, followed by C. coli (16%), C. upsaliensis (2.52%), C. fetus (1.26%) and Arcobacter cryaerophilus (0.84%). These findings have important implications for public health as C. jejuni is the species of Campylobacter most commonly involved in human campylobacteriosis. Campylobacter spp. isolates obtained during the study were preserved and are available to be used for further analysis. In fact, there has been some interest to use these isolates for multilocus sequence typing analysis. Epidemiological data regarding selected risk factors and the presence of Campylobacter in sheep and sheep carcasses was also obtained and analyzed during this study. The results from the epidemiological analysis are presented in a separate scientific paper including recommendations for the control of Campylobacter on sheep carcasses. The unexpected higher prevalence of Campylobacter in sheep found in this project might serve as motivation for future research studies. Furthermore, the methods used for isolation and identification of Campylobacter from sheep might be applicable to other animal species and/or other sources of Campylobacter.