Phylogenetic relationships and diversity of bat-associated Leptospira and the histopathological evaluation of these infections in bats from Grenada, West Indies

Bats can harbor zoonotic pathogens, but their status as reservoir hosts for Leptospira bacteria is unclear. During 2015–2017, kidneys from 47 of 173 bats captured in Grenada, West Indies, tested PCR-positive for Leptospira. Sequence analysis of the Leptospira rpoB gene from 31 of the positive samples showed 87–91% similarity to known Leptospira species. Pairwise and phylogenetic analysis of sequences indicate that bats from Grenada harbor as many as eight undescribed Leptospira genotypes that are most similar to known pathogenic Leptospira, including known zoonotic serovars. Warthin-Starry staining revealed leptospiral organisms colonizing the renal tubules in 70% of the PCR-positive bats examined. Mild inflammatory lesions in liver and kidney observed in some bats were not significantly correlated with renal Leptospira PCR-positivity. Our findings suggest that Grenada bats are asymptomatically infected with novel and diverse Leptospira genotypes phylogenetically related to known pathogenic strains, supporting the hypothesis that bats may be reservoirs for zoonotic Leptospira.