Epidemiology of Visceral Leishmaniasis in Bihar, India

Facilitating successful conduct of L. donovani transmission studies in India through infrastructure and technical capacity building

The Problem
Do any infected human populations disproportionately act as reservoirs for transmission of L. donovani (causes visceral leishmaniasis) to sand fly vectors, which can transmit the pathogen to uninfected humans perpetuating the disease cycle?
The Solution
The program facilitated successful conduct of studies through infrastructure/technical capacity building involving training technical staff, establishing a sand fly colony, evaluating technical feasibilities and addressing ethical concerns.

This project was completed in December 2016

Overview

In India, the sand fly vector Phlebotomus argentipes is responsible for the transmission of the protozoan parasite Leishmania donovani, which causes a disease called visceral leishmaniasis (VL), from one human to another. To better understand the parasite life cycle, the Epidemiology of Visceral Leishmaniasis in Bihar, India project sought to identify those L. donovani-infected humans that are the source of infection in the sand fly.

The FNIH project contributed infrastructure and resources that enabled a subsequent separately funded xenodiagnostic study led by collaborators at Banaras Hindu University and Kala-Azar Medical Research Centre to specifically identify those infected populations that disproportionately contribute to the transmission of visceral leishmaniasis in the endemic region of Bihar, India. There is no known animal reservoir of VL in this region and transmission is considered anthroponotic, i.e. the cycle  exists only of between humans and the sand fly vectors. Understanding whether individuals who are asymptomatically infected contribute to the maintenance of this infection cycle can help to target disease control efforts. Significant effort went into adapting wild-caught sandflies for the establishment of a continuous colony of “clean” uninfected sandflies that could be safely allowed to feed on humans with clinically distinct forms of L. donovani infection and disease. With support from U.S. sand fly experts, a number of hurdles were overcome and the colony was successfully established at the Kala Azar Medical Research Centre in Muzzafupur, India.  Capacity building and strengthening activities included:

i. Developing the necessary insectary infrastructure;

ii. Conducting technical training and evaluating technical feasibility;

iii. Addressing ethical challenges; and,

iv. Writing protocols for follow-on studies designed to define the relative ability of specific human-subject groups across the infection spectrum to serve as reservoirs of L. donovani infection to P. argentipes in areas of anthroponotic transmission.. Investigators collaborating on this project represented clinical, laboratory, epidemiological and regulatory expertise needed to conduct these studies. The FNIH was not involved in the support of the xenodiagnostic clinical trial.

Partners

Banaras Hindu University

Bill and Melinda Gates Foundation

Kala-Azar Medical Research Centre

National Institute of Allergy and Infectious Diseases  

FNIH Contact

Karen H. Tountas, Ph.D., Scientific Program Manager

ktountas@fnih.org

Publications

  • Tiwary, P., Singh, S.K., Kushwaha, A.K., et al. 2017. Establishing, Expanding, and Certifying a Closed Colony of Phlebotomus argentipes (Diptera: Psychodidae) for Xenodiagnostic Studies at the Kala Azar Medical Research Center, Muzaffarpur, Bihar, India. J. Med. Entomol. 54(5), 1129–1139. doi: 10.1093/jme/tjx099