Salmonella environmental persistence informs management relevant to avian and public health

Salmonellosis is a significant public health threat responsible for millions of human cases annually but is also of significance to domestic and wild animals around the globe. While human infections are often foodborne, an increasing number of cases arise from environmental sources and contact with animals, including wild birds. Understanding the persistence of Salmonella in shared environments is critical for mitigating zoonotic transmission risks and understanding transmission dynamics for pets and free-living wildlife. Two experiments were conducted to investigate Salmonella persistence on surfaces relevant to wild bird-people interactions. One was a controlled experiment to compare the persistence of an avian-derived Salmonella Typhimurium isolate on bird feeders made of different materials. A total of 9 (7%) swabs were culture positive for Salmonella. Although there was no statistical difference in prevalence rates and persistence, Salmonella was primarily reisolated from plastic feeders. The second experiment investigated the prevalence and persistence of Salmonella on picnic tables in a South Florida park that were contaminated with bird feces. Salmonella prevalence on the picnic tables was 27%. When tracking fecal piles over time, 33% to 42% of fecal piles were Salmonella culture positive for 1 to 4 days. A total of 13 to 14 serotypes were detected, of which 5 serovars are in the top 20 for human infections. Our trials indicate that Salmonella can persist on bird feeders and picnic tables and precautionary measures should be adopted to reduce exposure. The companion Currents in One Health by Seixas et al, JAVMA, forthcoming 2025, addresses in-depth information about Salmonella epidemiology in free-living birds.