Abstract

Salmonella spp. are frequently shed by wildlife including turtles, but S. enterica subsp. enterica serovar Typhimurium is rare in the latter. Moreover, the presence of lesions associated with Salmonella is unusual in chelonians. Using necropsy, immunohistochemistry, PCR, and culture, we showed that 11% of apparently healthy pelagic and 57% of stranded olive ridley turtles (Lepidochelys olivacea) on the Pacific coast of Central America, the continental United States, and Hawaii had renal granulomas associated with S. enterica ser. Typhimurium. The extent of renal lesions ranged from mild, focal granulomas to severe nephritis. Some animals were found during mass mortality events in Central America, suggesting that salmonellosis may have been a contributing cause. S. enterica ser. Typhimurium was the only species of Salmonella detected in olive ridley turtles, and phylogenetic analyses from whole-genome sequencing data showed that the isolates from olive ridley turtles formed a single clade distinct from other strains of S. enterica ser. Typhimurium. Although S. enterica ser. Typhimurium is known in coastal environments, its presence in olive ridley turtles within the oceanic environment is unexpected. Further study is warranted to determine the origin and host specificity of the olive ridley turtles S. enterica ser. Typhimurium strain as well as the potential role of salmonellosis in olive ridley turtle conservation. In addition, S. enterica ser. Typhimurium is one of the more common non-typhoidal Salmonella in humans, and olive ridley eggs are commonly harvested for human consumption in Central America, thus a potential for human exposure exists.