Isolation and Molecular Detection of pathogenic Leptospira spp from Wild Rodents (Rattus norvegicus) in Zaria and Its Environs, Kaduna State Nigeria

Abstract

Leptospirosis is a zoonotic disease caused by pathogenic serovars of Leptospira spp. Wild rodents (Rattus norvegicus) are considered principal reservoir for Leptospira spp. The aim of this study was isolation and identification of Leptospira spp circulating amongst wild rodent’s population in Zaria and its environs. Based on convenience sampling, three hundred and five (305) wild rodents (Rattus Norvegicus) from different locations in Zaria and its environs were trapped using 30 steel local wire traps (18+12+28 cm). The traps were baited with dry fish, groundnut, peanut and were placed in selected sampling points of abattoir, poultry farms, settled cattle farms, grain markets, feed stores and bushes. A total of 305 kidney tissue samples were collected aseptically into a sterile-labeled-sample bottles from the trapped wild rodents following euthanasia. Small pieces (2 cm) of the kidney tissues were cut off and placed into a sterile syringe without needle, and further squeezed into Ellinghausen-McCullough-Johnson-Harris (EMJH) media. The EMJH media with the inoculated kidney tissues were kept at 30oC in an incubator for 8 weeks before confirmation of positive isolates using dark field microscopy. Genomic DNA was extracted directly from 24 kidney tissue samples for molecular detection of pathogenic Leptospira spp. using polymerase chain reaction (PCR). The results of the culture indicates that the overall occurrence of Leptospira spp in wild rodents (Rattus norvegicus) was 57.70%, with 2.62% in NAPRI Shika, 2.85% in Angwan Rimi, 3.60% in Hunkuyi, 5.24% in Bomo, 8.52% in Bassawa 15.74% in Panhauya and 19.01% in Goruba respectively. The molecular characteristics of Leptospira spp. in the study location as indicated by distinct bands showed expected band size (423bp) indicative of pathogenic Leptospira spp. In conclusion, wild rodents may be source of infection to other domestic animals and man in Zaria and its environs evident from the high prevalence observed in this study, hence, raises serious public health concern.