Salmonella prevalence in laying hen farms and estimation of effective tools for controlling Salmonella infections
2020
Sasaki, Y. (Natuinal Institute of Health Sciences, Kawasaki, Kanagawa (Japan)) | Yonemitsu, K. | Uema, M. | Igimi, S. | Asakura, H.
This survey was conducted to determine Salmonella prevalence and to identify effective tools for controlling Salmonella infections in laying hen farms. Fresh cecal samples were obtained from a total of 56 laying hen farms between October 2017 and November 2019. Salmonella strains were isolated from nine laying hen flocks (8.0 %, 9/112 flocks) from seven farms. Salmonella prevalence in flocks injected with inactivated Salmonella vaccines (5.3 %, 5/95 flocks) was significantly lower than that in unvaccinated flocks (23.5 %, 4/17 flocks). Trivalent inactivated Salmonella vaccines consisting of Salmonella Enteritidis (O9 group), S. Typhimurium (O4 group), and S. Infantis (O7 group) were used in 82 flocks (73.2 %). Although Salmonella were isolated from five flocks injected with the trivalent vaccines, the O-antigens of Salmonella isolates from four flocks were of O8 and O13 groups (S. Altona, S. Corvallis, S. Albany, and 13,23:y:-). The O-antigen from the remaining one flock was from the O4 group (S. Haifa). On the other hand, O-antigens of Salmonella from four unvaccinated flocks were of O7 (S. Thompson and S. Infantis) and O18 (S. Cerro) groups. These results suggest that inactivated Salmonella vaccines are among the effective tools for controlling Salmonella infections in laying hen farms.
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