Nipah Virus, Bats and bamboo skirts

Often times the best, most cost effective way to suppress disease outbreaks is through prevention. We do this through vaccinations and washing our hands, and also through environmental interventions. 

One such environmental intervention has been proposed to quell outbreaks of Nipah Virus (NiV). NiV, an emerging infectious disease that causes acute encephalitis first isolated in 1998, has caused three separate outbreaks in Bangladesh over the last decade.

 In all three of these outbreaks the index case has been traced back to an individual who drank raw date sap (tira) and then spread the disease from person to person.  The pathway for how a person gets a virus from eating raw date sap may seem unclear but is actually very interesting.   

Fruit bats are an important pollinator in the forests of Bangladesh, but when farmers began tapping date palm trees for sap, the bats saw these sap collection targets as big bowls full of food. They frequented the sap bowls to drink and also often defecated in them as well. As resevior hosts of NiV, the bat guano contained the virus and then when humans came back to drink the raw date palm sap they became sick as well.   

 Researchers from Stanford devised woven bamboo covers that farmers could use to cover their sap containers and prevent bats from landing and drinking the sap from them.  They have run a course of three trials testing this intervention and have found no guano in the containers that had been covered. Also these covers may have helped prevent more outbreaks of NiV, but more work must be done to assert a higher level of correlation. 

- Chris LeBoa 

References:

Al, M. I. et. (n.d.). Nipah Virus Transmission from Bats to Humans Associated with Drinking Traditional Liquor Made from Date Palm Sap, Bangladesh, 2011–2014 - Volume 22, Number 4—April 2016 - Emerging Infectious Disease journal - CDC. https://doi.org/10.3201/eid2204.151747

Khan, S. U., Gurley, E. S., Hossain, M. J., Nahar, N., Sharker, M. A. Y., & Luby, S. P. (2012). A Randomized Controlled Trial of Interventions to Impede Date Palm Sap Contamination by Bats to Prevent Nipah Virus Transmission in Bangladesh. PLoS ONE, 7(8). https://doi.org/10.1371/journal.pone.0042689

Luby, S. P. (2013). The pandemic potential of Nipah virus. Antiviral Research, 100(1), 38–43. https://doi.org/10.1016/j.antiviral.2013.07.011

Luby, S. P., Rahman, M., Hossain, M. J., Blum, L. S., Husain, M. M., Gurley, E., … Ksiazek, T. G. (2006). Foodborne Transmission of Nipah Virus, Bangladesh. Emerging Infectious Diseases, 12(12), 1888–1894. https://doi.org/10.3201/eid1212.060732

Nahar, N., Mondal, U. K., Hossain, M. J., Khan, M. S. U., Sultana, R., Gurley, E. S., & Luby, S. P. (2014). Piloting the promotion of bamboo skirt barriers to prevent Nipah virus transmission through date palm sap in Bangladesh. Global Health Promotion, 21(4), 7–15. https://doi.org/10.1177/1757975914528249