Nipah virus (NiV) is an emerging zoonotic virus (a virus transmitted to humans from animals) that causes high mortality in humans. In addition to human-to-human transmission, epidemiological studies have identified another possible transmission pathway, namely from fruit bats of the Pteropodidae family to humans when people drink contaminated date palm sap. Human NiV cases in Bangladesh have been found to be seasonal, coinciding with the date palm harvesting season (November to March), and consumption of date palm wine appears to serve as a major portal for infection due to contamination of palm sap from contact with urine or saliva from infected fruit bats.
In addition to foodborne transmission pathways, animals other than bats may play a role in transmission. The project team has previously studied livestock during outbreak investigations, and as they expand their work under the current PEER grant they will pursue the hypothesis that multiple species of animals (including dogs, cats, cattle, goats, horses, and pigs) may acquire and spread Nipah infection during an outbreak. The Bangladeshi and U.S. researchers will develop sampline strategies and analytical approaches to assess the risk of infection via livestock and food-borne routes. In order to better understand the various possible routes of NiV transmission, this project will involve screening domestic, peri-domestic, and feral animals in a NiV outbreak to look for evidence of NiV infection. Furthermore, the researchers will look at bats’ date palm sap drinking behavior year round, in the locations where harvesters collect and ferment date palm sap for wine production. Beyond its research aspects, this project will also provide training in NiV surveillance, field sampling techniques, biosafety practices, and outbreak response for veterinarians under the Bangladeshi Department of Livestock Services, Ministry of Agriculture, and the Forestry Department.
Summary of Recent Activities
The team investigated four human Nipah outbreak sites in early 2013 (Bhaluka of Mymensingh, Charghat of Rajshahi, Atlanka and Zeropoint of Pabna) and collected roost urine from the bat roosts closest to each house where a Nipah case was found. Roost urine samples were found positive from two sites where the team will conduct the animal sero-survey portion of their study. The researchers also completed the first field trip for their camera study from February 28 through March 8, 2013. They first identified a climber, trained him, and hired him for eight days in order to set up the cameras. He also guarded the site overnight to keep the cameras from being stolen. As a result, the researchers have collected seven nights of camera observations showing the visits of 368 bats to date palm sap trees at the site, with their visits averaging 161 seconds in length. Future plans include initiating animal sampling at two outbreak sites (Pabna and Rajshahi) by May 2013.