, Volume 7, Issue 4, pp 517–525 | Cite as

Use of Infrared Camera to Understand Bats’ Access to Date Palm Sap: Implications for Preventing Nipah Virus Transmission

  • M. Salah Uddin Khan
  • Jahangir Hossain
  • Emily S. Gurley
  • Nazmun Nahar
  • Rebeca Sultana
  • Stephen P. Luby
Original Contribution


Pteropus bats are commonly infected with Nipah virus, but show no signs of illness. Human Nipah outbreaks in Bangladesh coincide with the date palm sap harvesting season. In epidemiologic studies, drinking raw date palm sap is a risk factor for human Nipah infection. We conducted a study to evaluate bats’ access to date palm sap. We mounted infrared cameras that silently captured images upon detection of motion on date palm trees from 5:00 pm to 6:00 am. Additionally, we placed two locally used preventative techniques, bamboo skirts and lime (CaCO3) smeared on date palm trees to assess their effectiveness in preventing bats access to sap. Out of 20 camera-nights of observations, 14 identified 132 visits of bats around the tree, 91 to the shaved surface of the tree where the sap flow originates, 4 at the stream of sap moving toward the collection pot, and no bats at the tap or on the collection pots; the remaining 6 camera-nights recorded no visits. Of the preventative techniques, the bamboo skirt placed for four camera-nights prevented bats access to sap. This study confirmed that bats commonly visited date palm trees and physically contacted the sap collected for human consumption. This is further evidence that date palm sap is an important link between Nipah virus in bats and Nipah virus in humans. Efforts that prevent bat access to the shaved surface and the sap stream of the tree could reduce Nipah spillovers to the human population.


bats date palm sap food contamination infrared camera nipah virus transmission 



This research study was funded by the United States Centers for Disease Control and Prevention (CDC) grant number 5U51CI00298-04, and the International Centre for Diarrhoeal Disease Research (ICDDR,B) grant number 00357. Its contents are solely the responsibility of the authors and do not necessarily represent the official views of the CDC or the ICDDR,B. ICDDR,B acknowledges with gratitude the commitment of CDC to the ICDDR,B’s research efforts. The authors thank our field research officer, Dr. Shahneaz Ali Khan, and date palm sap collector, Mr. Chitta Ranjan, for their efforts in the fieldwork. The authors also thank Dorothy Southern for assistance with writing the manuscript.


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Copyright information

© International Association for Ecology and Health 2011

Authors and Affiliations

  • M. Salah Uddin Khan
    • 1
  • Jahangir Hossain
    • 1
  • Emily S. Gurley
    • 1
  • Nazmun Nahar
    • 1
  • Rebeca Sultana
    • 1
  • Stephen P. Luby
    • 1
    • 2
  1. 1.PIDVS, HSID, ICDDR,BDhakaBangladesh
  2. 2.Centers for Disease Control and Prevention (CDC)AtlantaUSA

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