Molecular detection of pathogenic Leptospira in rodents captured in the municipality of Villavicencio, Colombia

Abstract

Leptospirosis is a bacterial zoonosis with great impact in public health and although it is a notifiable disease, it is considered a neglected disease since it mainly affects the poorest populations and with limited access to health services. Mammals, mainly rodents play an important role as hosts and reservoirs of pathogenic leptospiras. The main objective of this study was to detect the presence of Leptospira spp. through molecular analysis in rodents from peri-urban and rural areas belonging to the municipality of Villavicencio in Colombia. We conducted a transversal observational study between October 2018 and October 2019. Rural areas of the townships belonging to the municipality of Villavicencio were selected for sampling. Sherman-type traps were used, the rodents were anesthetized and after euthanasia the kid- neys were extracted and subsequently preserved in liquid nitrogen until their use. DNA was extracted using the comercial kit. Conventional PCR was carried out in search of the pfLp32 gene that is specific in Leptospira interrogans (sensu lato), the samples were sent to a company named “Macrogen” for sequencing. 50 rodents, 38 (76%) synanthropic and 12 (24%) wilds were collected. Of the 50 kidney tissue samples, 12% (6/50) were positive for the markers pfLp32 gene. The six samples corresponded Rattus rattus (4), Zygodontomys brevicauda (1) and Oligoryzomys sp (1). The alignment analysis carried out using the BlastN tool yielded coverage and identities of 98.64% which were close to the serovars Hardjo and Canicola. Serovars found in our study are related with reservoirs like cattle and dogs, what would lead to think in cross contamination by contaminated water. The importance of these wild species is that they can become maintenance hosts and may pose a potential risk for the human populations. In conclusion rodents, dogs, and cattle are part of the infectious cycle of leptospirosis in the municipality of Villavicencio.