Leptospiral renal colonization status in asymptomatic rural population of Tiruchirapalli district, Tamilnadu, India.

Humans are known to excrete leptospires in their urine after recovery from illness and there are reports showing development of asymptomatic leptospiruria in settings of high disease transmission. In this regard, we sought to evaluate the asymptomatic renal carriage status of humans in the highly endemic region of Tiruchirapalli district, Tamilnadu, India. A total of 245 asymptomatic participants were included. Urine and blood samples were collected and the extent of leptospiral infection was characterized by MAT, qPCR, 16S rRNA, and dot blot assay. The qPCR screening with urine DNA identified 129 (52.7%) positive samples further confirmed by nested PCR. The dot blot assay marked 30.2% (74/245) as true positives. The phylogenetic analysis showed the sequences to cluster with pathogenic Leptospira spp. Serological results showed 50 people with urine positivity to be negative for MAT and can probably be classified as 'asymptomatic individuals.' In conclusion, it can be speculated that in endemic regions there is a greater possibility of humans as maintenance host rather than incidental hosts.