Abstract
Raillietiella orientalis is an invasive pulmonary parasite that is native to Southeast
Asia and Africa and is rapidly spreading throughout Florida since its initial
identification in South Florida in 2012. This obligate parasite utilizes invertebrates,
anurans, and lizards as intermediate hosts and most often infects snakes as definitive
hosts. While parasitism causes minimal fitness consequences to snakes in the native
range of R. orientalis, in the introduced range it can cause severe infections in native
snake species, sometimes leading to mortality. Through collaborative and opportunistic
sampling, we examined snakes in the southeastern United States for R. orientalis
infection. We documented 14 new Florida county records of R. orientalis infection
in snakes sampled from August 2022 through October 2024. These new localities
fill gaps in the known geographic range of R. orientalis in Florida and extend the
parasite’s range 435 km northwest into the Florida panhandle. We also document
R. orientalis infections in four wild-caught snakes from South Florida that entered
the pet trade. Human-aided dispersal of intermediate hosts and snakes, including those
in the pet trade, is likely to rapidly increase the geographic range and conservation
threat of this invasive parasite. Our results highlight the importance of monitoring
biological invasions of parasites to clarify impacts on novel host species.
