Abstract
Raillietiella orientalis is a hematophagous pentastome that infects the respiratory tracts of its definitive host, most commonly snakes. Infections are associated with morbidity and mortality in native snakes in the United States, where R. orientalis is considered invasive. Raillietiella orientalis has been detected in snakes throughout Florida, mostly documented by opportunistic sampling of road-killed snakes since 2022 by Snake Lungworm Alliance and Monitoring (SLAM). To date, SLAM members have evaluated and sampled 1,537 snakes across the southeastern United States. SLAM has documented an expansion of 80 km northeast and 435 km northwest of the previously established range of R. orientalis , extended the known definitive host range to 19 native snake species and one native lizard, and documented R. orientalis in the pet trade. Here, we used SLAM’s snake dissection database to assess infection patterns in native snake species across latitudes, species, and body sizes. We found that R. orientalis infections are still limited to Florida, where 29.5% (228/773) of all individuals were infected. Sixteen of 33 (48%) snake species sampled exhibited R. orientalis infection, with the highest prevalences in eastern racers ( Coluber constrictor ; 61%), pygmy rattlesnakes ( Sistrurus miliarius ; 45%), banded water snakes ( Nerodia fasciata ; 42%), and common garter snakes ( Thamnophis sirtalis ; 33%). In Florida, lower latitude was a significant predictor of infection for Florida cottonmouths ( Agkistrodon conanti ), eastern racers, banded water snakes, rat snakes ( Pantherophis quadrivittatus/alleghaniensis ), and common garter snakes. Longer snout-vent length (SVL) was a significant predictor of infection for pygmy rattlesnakes, banded water snakes, and eastern racers, consistent with older snakes having more opportunity to develop infections. The influences of species, latitude, and SVL on R. orientalis infection highlight potential risk factors for wild snakes and are important considerations in future pathogen and conservation assessments.