A One Health Approach to Defining Animal and Human Helminth Exposure Risks in a Tribal Village in Southern India

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  • 1 Clinical and Translational Science Graduate Program, Tufts University Graduate School of Biomedical Sciences, Boston, Massachusetts;
  • 2 The Wellcome Trust Research Laboratory, Division of Gastrointestinal Sciences, Christian Medical College, Vellore, Tamil Nadu, India;
  • 3 Department of Community Medicine, Christian Medical College, Vellore, Tamil Nadu, India;
  • 4 Division of Geographic Medicine and Infectious Diseases, Tufts Medical Center, Tufts University School of Medicine, Boston, Massachusetts;
  • 5 Departments of Global Health, Medicine (Infectious Disease), Pediatrics and Epidemiology, University of Washington, Seattle, Washington;
  • 6 The DeWorm3 Project, University of Washington, Seattle, Washington;
  • 7 Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom

The high burden of soil-transmitted helminth infections has been studied in India; however, little data exist on zoonotic helminths, and on animal-associated exposure to soil-transmitted helminths. Our study took place in the Jawadhu Hills, which is a tribal region in Tamil Nadu, India. Using a One Health approach, we included animal and environmental samples and human risk factors to answer questions about the associations among infected household soil, domestic animals, and human risk factors. Helminth eggs were identified by microscopy in animal and soil samples, and a survey about risk factors was administered to the head of the household. Contact with animals was reported in 71% of households. High levels of helminth infections were found across domestic animal species, especially in goats, chickens, and dogs. Helminth eggs were recorded in 44% of household soil (n = 43/97) and separately in 88% of soil near a water source (n = 28/32). Animal contact was associated with 4.05 higher odds of having helminth eggs in the household soil (P = 0.01), and also having a water source at the household was associated with a 0.33 lower odds of having helminth eggs in the household soil (P = 0.04). Soil moisture was a mediator of this association with a significant indirect effect (P < 0.001). The proportion mediated was 0.50. While our work does not examine transmission, these results support consideration of animal-associated exposure to STH and potentially zoonotic helminths in future interventions to reduce helminth burden. Our study provides support for further investigation of the effects of animals and animal fecal matter on human health.

Author Notes

Address correspondence to Sitara Swarna Rao Ajjampur, Ida Scudder Road, Vellore, Tamil Nadu, India 632004. E-mail: sitararao@cmcvellore.ac.in

Financial support: The project was supported by a TL1 grant to A. S. from the National Center for Advancing Translational Sciences, National Institutes of Health, Award Number UL1TR002544. The content is solely our responsibility and does not necessarily represent the official views of the NIH. The project was also supported by a Fellowship Grant from the Tufts’ Institute of the Environment to A. S. The DeWorm3 study is funded through a grant to the Natural History Museum, London from the Bill and Melinda Gates Foundation (OPP1129535, PI JLW).

Authors’ addresses: Alexandra Sack, Tufts Clinical and Translational Science Institute, Tufts Graduate School of Biomedical Sciences, Boston, MA, E-mail: alexandra.sack@tufts.edu. Gokila Palanisamy, Malathi Manuel, Chinnaduraipandi Paulsamy, Saravanakumar Puthupalayam Kaliappan, and Sitara Swarna Rao Ajjampur, The Wellcome Trust Research Laboratory, Division of Gastrointestinal Sciences, Christian Medical College, Vellore, Tamil Nadu, India, E-mails: gokilap01896@gmail.com, malathimanuel25@gmail.com, chechinnadurai@gmail.com, epipks@gmail.com, and sitararao@cmcvellore.ac.in. Anuradha Rose, Department of Community Medicine, Christian Medical College, Vellore, Tamil Nadu, India, E-mail: anurose@cmcvellore.ac.in. Honorine Ward, Division of Geographic Medicine and Infectious Diseases, Tufts Medical Center, Tufts University School of Medicine, Boston, MA, E-mail: hward@tuftsmedicalcenter.org. Judd L. Walson, Departments of Global Health, Medicine (Infectious Disease), Pediatrics and Epidemiology, University of Washington, Seattle, WA, E-mail: walson@uw.edu. Katherine E. Halliday, Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom, E-mail: katherine.halliday@lshtm.ac.uk.

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