Enumerating genotypic diversity and host specificity of G in wild rodents around a New York watershed.

is a genus of flagellated protozoans that parasitize the gastrointestinal tract of humans and wildlife worldwide. While is well-studied due to its potential to cause outbreaks of diarrheal illness in humans, other species from wildlife have been largely understudied. This study examines the occurrence, host specificity, and genotypic diversity of in wild rodents living within the New York City water supply watershed. A novel nested PCR assay targeting the 18S ssu-rDNA gene is introduced, which captures nearly the entire gene for improved species-level determination versus existing molecular typing methods. Molecular characterization of 55 specimens reveals at least seven novel lineages. Phylogenetic analysis indicates a close relationship between the newly characterized lineages and rodent hosts, suggesting rodents as important reservoirs of and its close relatives. These findings provide insights into the diversity of species and their public health potential in localities with human-wildlife interaction and further emphasizes the need for continued efforts to improve the molecular tools used to study microbial eukaryotes, especially those with zoonotic potential.