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Amanda Smith Dissertation.pdf (1.23 MB)

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The Epidemiology of Canine Leptospirosis in the United States

Smith, Amanda Michelle
http://rave.ohiolink.edu/etdc/view?acc_num=osu1592518946269083

Abstract Details

2020, Doctor of Philosophy, Ohio State University, Comparative and Veterinary Medicine.
Canine leptospirosis is a reemerging zoonotic disease of concern in North America. Leptospira spp. are tightly coiled spirochetes shed in urine and transmitted by maintenance hosts, such as rats, mice, and raccoons. Dogs acquire the bacteria from direct contact of mucous membranes or broken skin with urine of infected individuals or contact with food, water, or soil contaminated with infectious urine. Leptospirosis can cause a wide spectrum of clinical illness in canines, ranging from subclinical to severe hepatic or renal failure, with the possibility of death. Much is still unknown about canine leptospirosis and a better understanding of its epidemiology is needed. In the United States, the microscopic agglutination test (MAT) has been widely used to diagnose leptospirosis in dogs, but polymerase chain reaction (PCR) leptospirosis testing has become increasingly used in clinical veterinary medicine in recent years and may reduce the interpretation challenges commonly encountered with MAT. Data from 40,118 canine leptospirosis PCR tests run in the United States between 2009 and 2016 were evaluated in combination with climate and socioeconomic data from public databases. Overall test-positive proportion was 5.4% across the United States. Generalized mixed logistic regression models accounting for county within state identified significant predictors for a positive test, including male sex, 0-4 years of age, and living in areas with wet environmental conditions. To identify and describe clusters of the 40,118 PCR canine Leptospira spp. test results in space and time across the US, spatio-temporal clusters for real-time PCR positive test results were identified using the space-time permutation scan statistic and the centroid of the zip code reported for each test. Seven significant space-time clusters of Leptospira spp. real-time PCR positive test results were identified across the US: one each located within the states of Arizona (2016), California (2014-2015), Florida (2010), South Carolina (2015), and one each located within the south-central region (2015), midwest region (2014), and northeast region (2011). Clusters were identified in new areas when compared to previous work by others, demonstrating the complex epidemiology of this disease. Since canine leptospirosis has been commonly identified in major cities in the United States, a case-control study was conducted in Chicago, Illinois. Data were obtained from two veterinary practices in Chicago, Illinois on 45 canine leptospirosis cases diagnosed 2015 through 2018, and 180 time-matched controls. The case-fatality rate was 29% and cases were hospitalized for an average of 3.8 days. Canine leptospirosis cases were predominately young (<1 year of age), small (≤6.6kg), intact dogs. Canine leptospirosis vaccination was identified as a protective factor. To investigate veterinarian vaccination practices and prevention recommendations veterinarians make to clients, a qualitative study was conducted utilizing semi-structured interviews with a convenience sample of veterinarians in Columbus, Ohio. Eleven veterinarians were interviewed, and all recommended the canine leptospirosis vaccine to their clients. The main themes identified included: most felt canine leptospirosis is a public health duty, mixed concern about leptospirosis vaccine reactions, dog breeder recommendations are a barrier to vaccination, and reported infrequent use of canine leptospirosis diagnostic tests.
Thomas Wittum (Advisor)
Jason Stull (Advisor)
Armando Hoet (Committee Member)
Barbara Piperata (Committee Member)
160 p.
Epidemiology
canine; leptospirosis; epidemiology

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Citations

  • Smith, A. M. (2020). The Epidemiology of Canine Leptospirosis in the United States [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1592518946269083

    APA Style (7th edition)

  • Smith, Amanda. The Epidemiology of Canine Leptospirosis in the United States. 2020. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1592518946269083.

    MLA Style (8th edition)

  • Smith, Amanda. "The Epidemiology of Canine Leptospirosis in the United States." Doctoral dissertation, Ohio State University, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=osu1592518946269083

    Chicago Manual of Style (17th edition)

osu1592518946269083
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This open access ETD is published by The Ohio State University and OhioLINK.