A bat licking sap from the shaved part of a date palm tree (Photo courtesy Dr. Khan).
Two rats licking sap from the shaved part of a date palm tree( Photo courtesy Dr. Khan).
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 sampling 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
During the final quarter of 2014, Dr. Khan and the project team collected 21 nights of camera observation data (one week each month) of bat visits to date palm sap trees. There were 2529 bats total, which peaked at 1302 in November.
The team’s data organization and analysis is ongoing after which an abstract will be prepared for submission at an international conference. The team has taken all necessary steps for its Nipah outbreak investigation and will sample bat roosts from all sites with confirmed human Nipah cases. Blood will also be collected from domestic and peri-domestic animals from two human Nipah outbreak sites.