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

Dawn Spangler,Ashutosh Verma,Michele D. Coarsey,Brittney Beigel,Joey Morgan,Vinayak K. Nahar,Daniel Kish,Karen Gruszynski,Hemant Naikare,Kalimuthusamy Natarajaseenivasan

doi:10.1371/journal.pone.0228038

Abstract

BackgroundLeptospirosis, 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.MethodsIn 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.ResultsA 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.ConclusionsThese findings have significant implications regarding animal and public health in the Cumberland Gap Region and possibly outside where these animals may be adopted.

Highlights

Leptospirosis, caused by pathogenic Leptospira spp., is a waterborne zoonotic infection that affects dogs and many other mammalian species [1,2,3]
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 that targets pathogen-associated lipl32 gene
All cats tested negative by both quantitative PCR (qPCR) and microscopic agglutination test (MAT)

Summary

Introduction

Leptospirosis, caused by pathogenic Leptospira spp., is a waterborne zoonotic infection that affects dogs and many other mammalian species [1,2,3]. Leptospiral infection in dogs can result in a serious clinical outcome, such as acute hepatorenal failure, or it can lead to asymptomatic chronic carrier state [6]. Canine leptospirosis testing data collected over a period of 14 years in the United States was analyzed to develop predictive models for identifying regions of increased risk for leptospirosis. Leptospirosis, caused by pathogenic Leptospira spp., is a zoonotic infection that affects humans, dogs and many other mammalian species. 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

Results

Conclusion