Agricultural Research Management Information System

Home
Research Summary
Search
About Us
- ARMIS
- Brochure
Contact Us
Report
User Request
Data Input
Help
- Operation Manual
  - PDF
  - Video
- Program Area & Commodity
We have reached 37600 number of research entries at this moment.

- Logout

Research Detail

Home
Research
Detail

A Randomized Controlled Trial of Interventions to Impede Date Palm Sap Contamination by Bats to Prevent Nipah Virus Transmission in Bangladesh

Salah Uddin Khan*
International Centre for Diarrhoeal Disease Research, Bangladesh (ICDDR,B), Dhaka, Bangladesh

Emily S. Gurley
International Centre for Diarrhoeal Disease Research, Bangladesh (ICDDR,B), Dhaka, Bangladesh

M. Jahangir Hossain
International Centre for Diarrhoeal Disease Research, Bangladesh (ICDDR,B), Dhaka, Bangladesh

Nazmun Nahar
International Centre for Diarrhoeal Disease Research, Bangladesh (ICDDR,B), Dhaka, Bangladesh

M. A. Yushuf Sharker
International Centre for Diarrhoeal Disease Research, Bangladesh (ICDDR,B), Dhaka, Bangladesh

Stephen P. Luby
1. International Centre for Diarrhoeal Disease Research, Bangladesh (ICDDR,B), Dhaka, Bangladesh, 2. Centers for Disease Control and Prevention (CDC), Atlanta, Georgia, United States of America

Abstract/ Executive Summary:

Background:Drinking raw date palm sap is a risk factor for human Nipah virus (NiV) infection. Fruit bats, the natural reservoir of NiV, commonly contaminate raw sap with saliva by licking date palm’s sap producing surface. Evaluated four types of physical barriers that may prevent bats from contacting sap.

Methods:During 2009, used a crossover design and randomly selected 20 date palm sap producing trees and observed each tree for 2 nights: one night with a bamboo skirt intervention applied and one night without the intervention. During 2010, selected 120 trees and randomly assigned four types of interventions to 15 trees each: bamboo, dhoincha (local plant), jute stick and polythene skirts covering the shaved part, sap stream, tap and collection pot. We enrolled the remaining 60 trees as controls. We used motion sensor activated infrared cameras to examine bat contact with sap.

Results:During 2009 bats contacted date palm sap in 85% of observation nights when no intervention was used compared with 35% of nights when the intervention was used. Bats were able to contact the sap when the skirt did not entirely cover the sap producing surface. Therefore, in 2010 we requested the sap harvesters to use larger skirts. During 2010 bats contacted date palm sap less frequently in trees protected with skirts compared to control trees. No bats contacted sap in trees with bamboo, dhoincha skirt (p<0.001) or polythene covering (p<0.001), but bats did contact sap during one night (7%) with the jute stick skirt.

Conclusion:Bamboo, dhoincha, jute stick and polythene skirts covering the sap producing areas of a tree effectively prevented bat-sap contact. Community interventions should promote applying these skirts to prevent occasional Nipah spillovers to human.

Keywords: Impede, Date Palm Sap, Contamination, Bats, Nipah Virus Transmission, Bangladesh

Location:

Start Date:

End Date:

Program Area: Pest Management

Commodity: Diseases, Date palm

Objectives:

To evaluate the different (four) types of physical barriers that may prevent bats from contacting sap of date palm.

Methodology:

Study Settings: Two trials was conducted in Poromanandopur village in Faridpur district during two sap harvesting seasons: first from January 2009 through February 2009 and second was from November 2009 through March 2010 period. The interventions included bamboo, dhoincha, jute stick, and polythene skirts to cover the sap producing surface of the tree. During 2009, it compared the number of times bats contacting sap to trees with and without bamboo skirt intervention. During 2010, it compared the number of times bats contacting the sap to trees with interventions by bamboo, jute stick, dhoincha, and polythene skirts and the bats contacting the sap to trees without any intervention. Identified 54 date palm sap producing trees prepared for sap harvesting by a sap harvester in the village. The trees were tall enough so that terrestrial animals, including dogs and foxes, could not reach the sap producing surface and were trees that the harvesters frequently noticed bats visiting. Using Microsoft Excel, generated 20 random numbers between 1 and 54 in order to select 20 trees. Each tree was observed for one night with the intervention and for one night without any intervention. A sap harvester from the study village estimated the average size of the sap collecting area of a date palm tree and made the bamboo skirts that used for the intervention. Ten trees were randomly selected to be observed with intervention and 10 were observed without interventions during the first 10 nights of data collection. During the second 10 nights of data collection, the trees were assigned to the opposite group. Every night, observed two newly shaved date palm trees: one with the bamboo skirt intervention and the other without any intervention so that the observations were matched in terms of time. The date palm sap harvester mounted two infrared cameras (Silent ImageTM Model RM30 digital cameras on the trees before dusk, one camera per tree. The cameras were triggered by a motion sensor and were focused on the shaved surface, sap stream, tap and the opening of the collection pot. This way, it observed all 20 trees for two nights each; one night with the bamboo skirt applied and one night without the intervention. Selecting Date Palm Trees for Intervention and Control During 2010 During 2010, it identified 277 tall date palm sap producing trees prepared for sap harvesting by eight sap harvesters in the same village. From those, selected 60 trees as controls by the random selection process described above. From the remaining 217 trees, identified potential matches for the controls by comparing their apparent height, shaving pattern of the trunk of the tree. For every control tree, there was more than one potential match. Again entered the tree numbers in Microsoft Excel and generated random numbers to select one tree to receive the skirt interventions for each control. Of the 60 trees selected for intervention, assigned four interventions: bamboo, dhoincha, jute stick and polythene skirts to cover the shaved surface, sap stream, tap, and collection pot for 15 trees each. Trees for each intervention were assigned by generating random numbers in Microsoft Excel. It followed the same procedures as in 2009 for mounting the cameras and observing a matched pair of trees per night. During this season, hired the same sap harvester who worked during 2009 to prepare skirts and mount cameras on trees prepared by 10 different date palm sap harvesters in the village. The sap harvester placed one of the three size skirts that entirely covered the shaved surface, sap stream, tap, and collection pot hung on the tree. Observation and Data Collection: Briefly, an infrared camera was placed for one night per tree from 5:00 PM to 6:00 AM; that defined as a ‘‘camera-night’’ of observation. If there was any movement in the sap collection area the camera took one picture per second for the next five seconds. In the morning, the camera was taken down from the tree and the pictures were transferred to a computer and reviewed. During the data extraction process it counted all species of fruit bats and defined a ‘‘bat visit’’ as an instance where could identify a bat flying and/or landing on and around the tree. It defined an event of ‘‘bat-sap contact’’ as an instance of a bat landing, licking, or urinating either on the date palm’s shaved surface, sap stream, tap or collection pot that comes in contact with the sap. Data Analysis: It used descriptive statistics to summarize the frequency of bat visits with and without interventions placed in the trees. That used conditional logistic regression to assess the association between frequency of the events of bat-sap contact with the presence or absence of interventions; and calculated odds ratios. A paired t test to assess the difference of the volume of sap production and price with or without interventions.

Source of Information: PLoS ONE, www.plosone.org August 2012, Volume 7, Issue 8, e42689

Article Link (Online Journal): http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0042689

Funding Source:

Budget:

Total Budget (Tk.) :

Achievement/Findings:

Bamboo, dhoincha, jute stick and polythene skirts covering the sap producing areas of a tree effectively prevented bat-sap contact. Community interventions should promote applying these skirts to prevent occasional Nipah spillovers to human.

Knowledge Management: Journal