25 September 2026
A nationwide study published in Poultry Science provides an extensive overview of Salmonella epidemiology in commercial broiler breeder flocks in Israel between 2008 and 2018. The study was conducted by researchers Anat Wiseman, Hadas Poria Daly, and Ehud Elnekave from the Poultry Health Laboratories of the Egg and Poultry Board and the Koret School of Veterinary Medicine at the Hebrew University of Jerusalem.
Analyzing data from the national surveillance program, encompassing a full census of 4,100 flocks across 142 farms and 64,217 environmental test results, the researchers found that, on average, 29.6% of flocks and 59.6% of farms tested positive for Salmonella at least once annually. Cumulatively over the 11-year study period, 40.0% of flocks and 91.5% of farms tested positive at least once. These flock-level rates are comparable to levels observed in North America and Australia, but substantially exceed those reported in the European Union (~2%).
- The likelihood of detection peaked in the autumn compared to winter, spring, and summer.
- Younger flocks (≤45 weeks of age, coinciding with the onset and peak of laying) had significantly higher odds of testing positive compared to older flocks (>45 weeks).
- Flocks of the Ross breed showed a significantly higher risk of infection compared to Cobb and other breeds.
- The Central district exhibited higher detection odds than the Southern district.
- Samples collected by official Israeli Veterinary Services (IVS) inspectors yielded a higher detection rate than those taken by poultry growers.
- Approximately 70% of positive flocks experienced repeated detections in subsequent samplings. Older age at first detection (>45 weeks) and the Ross breed were significantly associated with increased odds of repeated detections.
A total of 91 distinct serotypes were identified, with five dominant serotypes accounting for 67% of all isolates: S. Infantis (29.0%), S. Hadar (12.2%), S. Kentucky (11.9%), S. Muenchen (8.1%), and S. Virchow (6.1%).
S. Infantis: Infantis peaked in 2011, accounting for 46.3% of isolates. Following the mandatory vaccination of all breeding flocks against S. Infantis introduced in late 2011, its prevalence declined to 6.7% by 2018.
S. Muenchen: Concurrently, S. Muenchen rose sharply from 1.9% in 2008 to 31.7% in 2018, becoming the dominant serotype in broiler breeders - largely driven by the acquisition of the multidrug-resistant megaplasmid pESI.
When comparing poultry isolates with human clinical surveillance data, the researchers noted a marked overlap among major serotypes - notably Infantis, Muenchen, Hadar, and Virchow - reinforcing the broiler production chain's role as a potential zoonotic transmission route. Conversely, S. Enteritidis and S. Typhimurium, which represent leading causes of human salmonellosis, were virtually absent in broiler breeders (0.1% each). This finding demonstrates the effectiveness of the national policy mandating the culling of breeding flocks infected with these two serovars (and a strict vaccination protocol – N.E), indicating that table eggs, rather than poultry meat, serve as their primary reservoir.
Wiseman et al (2026). Salmonella in broiler breeder flocks in Israel during 2008–2018: Prevalence, risk factors and repeated detections. Poultry Science, 105, 107766.
