Leptospiral shedding and seropositivity in shelter dogs in the Cumberland Gap Region of Southeastern Appalachia.

BACKGROUND: Leptospirosis, caused by pathogenic Leptospira spp., is a zoonotic infection that affects humans, dogs and many other mammalian species. Virtually any mammalian species can act as asymptomatic reservoir, characterized by chronic renal carriage and shedding of a host-adapted leptospiral serovar. Environmental contamination by chronic shedders results in acquisition of infection by humans and susceptible animals. METHODS: In this study, we investigated if clinically normal shelter dogs and cats harbor leptospires in their kidneys by screening urine samples for the presence of leptospiral DNA by a TaqMan based-quantitative PCR (qPCR) that targets pathogen-associated lipl32 gene. To identify the infecting leptospiral species, a fragment of leptospiral rpoB gene was PCR amplified and sequenced. Additionally, we measured Leptospira-specific serum antibodies using the microscopic agglutination test (MAT), a gold standard in leptospiral serology. RESULTS: A total of 269 shelter animals (219 dogs and 50 cats) from seven shelters located in the tri-state area of western Virginia, eastern Tennessee, and southeastern Kentucky were included in this study. All cats tested negative by both qPCR and MAT. Of the 219 dogs tested in the study, 26/198 (13.1%, 95% CI: 8.4-17.8%) were positive for leptospiral DNA in urine by qPCR and 38/211 (18.0%, 95% CI: 12.8-23.2%) were seropositive by MAT. Twelve dogs were positive for both qPCR and MAT. Fourteen dogs were positive by qPCR but not by MAT. Additionally, leptospiral rpoB gene sequencing from a sub-set of qPCR-positive urine samples (n = 21) revealed L. interrogans to be the leptospiral species shed by dogs. CONCLUSIONS: These findings have significant implications regarding animal and public health in the Cumberland Gap Region and possibly outside where these animals may be adopted.

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.

Leptospira: Molecular Detection of Pathogenic Species in Natural Sources.

This protocol describes a method for the rapid detection of leptospiral DNA in environmental water. In summary, the DNA is extracted from water samples and tested in a TaqMan-based real-time quantitative polymerase chain reaction (qPCR) for the presence of lipl32, a gene that is present only in pathogenic Leptospira spp. The gene target used in this assay is important in that it only detects pathogenic leptospires and not the saprophytic leptospires that may be present in environmental samples. © 2017 by John Wiley & Sons, Inc.

Detection of Leptospiral DNA in the Urine of Donkeys on the Caribbean Island of Saint Kitts.

Leptospirosis is a global zoonosis caused by pathogenic spirochetes classified within the genus Leptospira. Leptospires live in the proximal renal tubules of reservoir or chronic carrier animals, and are shed in the urine. Naïve animals acquire infection either when they come in direct contact with a reservoir or infected animals or by exposure to environmental surface water or soil that is contaminated with their urine. In this study, urine samples from a herd of donkeys on the Caribbean island of St. Kitts were screened using a TaqMan-based real-time quantitative polymerase chain reaction (qPCR) targeting a pathogen-specific leptospiral gene, lipl32. Out of 124 clinically normal donkeys, 22 (18%) tested positive for leptospiral DNA in their urine. Water samples from two water troughs used by the donkeys were also tested, but were found to be free from leptospiral contamination. Detection of leptospiral DNA in the urine of clinically healthy donkeys may point to a role that these animals play in the maintenance of the bacteria on St. Kitts.