Comparison of the association of age with the infection of Salmonella and Salmonella enterica Serovar Typhimurium in Pekin ducks and Roman geese.

Nontyphoid Salmonella have a broad host range in poultry and mammals, and serovar Typhimurium is a threat to public health. In this study, normal and sick ducks and geese were collected from 12 farms in Taiwan to investigate the age-associated infection of Salmonella and Salmonella Typhimurium in Roman geese (Anser anser domesticus) and Pekin ducks (Anas platyrhynchos domesticus). In normal birds, the prevalence of Salmonella differed between species, and with age [e.g., 1-wk group, 37.5% (30/80) for ducks and 5.2% (6/116) for goslings (P < 0.05) vs. 4-wk group, 1% (1/96) for ducks and 12.1% (21/174) for geese]. Salmonella Typhimurium was identified from the visceral organs of moribund young geese suffering with colibacillosis and riemerellosis isolated from 2 goose farms (farm A and B, respectively). At farm B, 22.9% (27/118) of 4-wk geese with diarrhea were Salmonella Typhimurium-positive compared with 4.6% (8/174) of 4-wk normal geese. All Salmonella Typhimurium strains except one harbored a 94.7-kb virulence plasmid. Subcutaneous injection of Salmonella Typhimurium isolate 91NGL1 resulted in different clinical signs and pathogenesis between ducks and geese. In addition, the mean infectivity dose ratios of ducks to geese were 3.2 and 85.0 for 4- and 12-d birds, respectively, suggesting that goslings were more susceptible to Salmonella Typhimurium and resistance to Salmonella Typhimurium increased with age, especially for ducks. Therefore, Salmonella Typhimurium infection should be more common in goose farms than in duck farms, especially in the younger birds.