Evidence of Leptospiral Presence in the Cumberland Gap Region.

Background: Leptospirosis is a widespread zoonotic disease that causes reproductive losses and/or hepatorenal failure in a number of animal species. Wild reservoirs of the disease, such as rodents, harbor the causative bacterium, Leptospira spp., in their kidneys and contaminate the environment by excreting infected urine. In this study, we tested small wild mammals, environmental water, and livestock in the Cumberland Gap region of southeastern Appalachia for the presence of pathogenic Leptospira or leptospiral antibodies. Methods/Results: Small wild mammals (n = 101) and environmental water samples (n = 89) were screened by a real time quantitative PCR that targets the pathogenic Leptospira-specific lipl32 gene. Kidneys from 63 small wild mammals (62.37%) and two water sources (2.25%) tested positive for leptospiral DNA. To identify the infecting leptospiral species in qPCR-positive water and kidney samples, a fragment of leptospiral rpoB gene was PCR amplified and sequenced. L. kirschneri and L. interrogans were the leptospiral species carried by small wild mammals. Furthermore, sera from livestock (n = 52; cattle and horses) were screened for leptospiral antibodies using microscopic agglutination test (MAT). Twenty sera (38.46%) from livestock had antibodies to one or more serovars of pathogenic Leptospira spp. Conclusions: In conclusion, results from our study show exposure to leptospiral infection in farm animals and the presence of this zoonotic pathogen in the environmental water and kidneys of a significant number of small wild mammals. The public health implications of these findings remain to be assessed. Author summary: Leptospirosis, a zoonotic disease caused by Leptospira, affects people and animals, including dogs, cows and horses. Many species of small mammals, and particularly rodents, are believed to be natural reservoirs of the pathogen across numerous geographical ranges with similar climatic conditions. The Cumberland Gap region (CGR) in southern Appalachia has several climatic risk factors for leptospirosis. With this in mind, we tested surface water, kidneys of small wild mammals, and blood from cows and horses in the CGR for the presence of leptospiral DNA or antibodies. Notably, more than 60% of tested small mammals carried leptospires in their kidneys. Furthermore, we found that 2 of the 89 tested environmental water samples contained leptospiral DNA, and a significant percentage of cows and horses had leptospiral antibodies. These findings will advance our understanding of the ecology of leptospirosis in the region, which will lead to stakeholder awareness, and development of preventive interventions with broad applicability within and outside this region of southern Appalachia. [ABSTRACT FROM AUTHOR]