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Cattle, sheep and goats may transmit leptospirosis to humans in Tanzania

PLOS

Leptospirosis, which affects more than one million people worldwide each year, is known to be transmitted to humans from a wide range of animals. Now, researchers reporting in PLOS Neglected Tropical Diseases have discovered that more than 7 percent of the cattle and 1 percent of sheep and goats in local slaughterhouses in northern Tanzania are infected with Leptospira bacteria.

Leptospirosis is a disease caused by infection with bacteria of the genus Leptospira. In humans, the disease can range in severity from mild to severe disease leading to kidney damage, liver failure, or death. The disease is most common in tropical environments, but occurs worldwide, particularly in people who work outdoors or with animals. Acute leptospirosis is an important cause of febrile disease in Tanzania, where little is known about the most common sources of infection in humans.

In the new work conducted in northern Tanzania, Kathryn Allan, of the University of Glasgow, UK, and colleagues tested rodents, cattle, goats and sheep for Leptospira infection. Animals were sampled in the catchment areas of two hospitals that had high prevalence of patients with leptospirosis. Small samples of kidney tissue were collected and used to test for the bacteria.

Among 384 trapped rodents trapped, no animals were found to carry Leptospira infection. In contrast, Leptospira was detected in kidney samples from 7.1% of cattle, 1.2% of goats, and 1.1% of sheep. As well as having a high prevalence of infection, cattle were found to be carrying four different types of Leptospira bacteria, all of which have the potential to cause disease in people.

"Our study makes a substantial contribution to the growing body of evidence that livestock, especially cattle, play an important role in the epidemiology of human leptospirosis in sub-Saharan Africa," the researchers say. "Our findings support recent hospital studies that have identified cattle farming as a major risk factor for human infection. Understanding the factors that support the transmission of Leptospira from livestock to people are important priorities for future public health research and could help us develop effect control measures to reduce both human and animal infection."

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In your coverage please use this URL to provide access to the freely available article in PLOS Neglected Tropical Diseases: http://journals.plos.org/plosntds/article?id=10.1371/journal.pntd.0006444

Citation: Allan KJ, Halliday JEB, Moseley M, Carter RW, Ahmed A, et al. (2018) Assessment of animal hosts of pathogenic Leptospira in northern Tanzania. PLOS Neglected Tropical Diseases 12(6): e0006444. https://doi.org/10.1371/journal.pntd.0006444

Funding: This work was supported by the Wellcome Trust (grant number 096400/Z/11/Z; https://wellcome.ac.uk/). Jo Halliday, Venance Maro, John Crump, and Sarah Cleaveland received support from the Research Councils UK, UK Department for International Development, and UK Biotechnology and Biological Sciences Research Council (BBSRC) (grant numbers BB/J010367/1, BB/L018926, BB/L017679, BB/L018845; http://www.bbsrc.ac.uk/). John Crump and Venance Maro also received support from the US National Institutes of Health (NIH)-National Science Foundation (NSF) Ecology and Evolution of Infectious Disease program (R01TW009237; https://www.fic.nih.gov/programs/pages/ecology-infectious-diseases.aspx). Mark Moseley received support from the BBSRC East of Scotland Bioscience Doctoral Training Partnership (http://www.eastscotbiodtp.ac.uk/). Michael Maze received support from a University of Otago Frances G. Cotter Scholarship and a University of Otago MacGibbon PhD Travel Fellowship (http://www.otago.ac.nz/). Venance Maro and John Crump received support from the US National Institutes of Health National Institute for Allergy and Infectious (grant number R01 AI121378; https://www.niaid.nih.gov/). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Competing Interests: The authors have declared that no competing interests exist.

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