Prevalence of and examination of exposure factors for Salmonella on commercial egg-laying farms in Barbados.

During January-March 2009, an outbreak of Salmonella was diagnosed in four commercial egg-laying farms in Barbados. During the outbreak, 511 layers died while 3257 layers were voluntarily culled from one affected farm. Salmonella ser Enteritidis was identified in avian tissues (ovaries, liver, and uterus), and egg samples submitted to the Ministry of Agriculture, Food, Fisheries, and Water Resource Management (MAFFW) Veterinary Services (VS) Laboratory by managers of the affected farms. As a result of this outbreak, MAFFW VS conducted a survey to investigate the prevalence of Salmonella on commercial egg-laying farms in Barbados. In addition, the relationships between farm-level exposure factors and diagnosis of Salmonella were examined. This paper describes the results of this survey. Nineteen of 26 farms (73%; 95% CI=56-90%) were classified as positive for Salmonella. The odds of testing positive for Salmonella were 10 times higher in large farms, compared to small farms (OR=10.80; 95% CI=1.01, 115.10; p=0.04). More small farms (8/11) cleaned and disinfected poultry facilities quarterly or more often than large farms did (1/10) (p<0.01). Prevalence of Salmonella in commercial egg-laying farms in Barbados is high. Salmonella ser Enteritidis was the most common serotype identified in study farms, and this is a public health issue of concern. This is the first prevalence survey of Salmonella in egg-laying farms in Barbados. Study results can be used as a baseline for future control programmes aimed at reducing the prevalence of Salmonella in egg-laying farms in the country.