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Spatial characterization of colonies of the flying fox bat, a carrier of Nipah virus in Thailand.

Thanapongtharm W, Linard C, Wiriyarat W, Chinsorn P, Kanchanasaka B, Xiao X, Biradar C, Wallace RG, Gilbert M - BMC Vet. Res. (2015)

Bottom Line: While no evidence of infection in domestic pigs or people has been found to date, pig farming is an active agricultural sector in Thailand and therefore could be a potential pathway for zoonotic disease transmission from the bat reservoirs.Flying fox colonies are found mainly on Thailand's Central Plain, particularly in locations surrounded by bodies of water, vegetation, and safe havens such as Buddhist temples.Such proactive planning would help conserve flying fox colonies and should help prevent zoonotic transmission of Nipah and other pathogens.

View Article: PubMed Central - PubMed

Affiliation: Department of Livestock Development (DLD), Bangkok, Thailand. weeraden@yahoo.com.

ABSTRACT

Background: A major reservoir of Nipah virus is believed to be the flying fox genus Pteropus, a fruit bat distributed across many of the world's tropical and sub-tropical areas. The emergence of the virus and its zoonotic transmission to livestock and humans have been linked to losses in the bat's habitat. Nipah has been identified in a number of indigenous flying fox populations in Thailand. While no evidence of infection in domestic pigs or people has been found to date, pig farming is an active agricultural sector in Thailand and therefore could be a potential pathway for zoonotic disease transmission from the bat reservoirs. The disease, then, represents a potential zoonotic risk. To characterize the spatial habitat of flying fox populations along Thailand's Central Plain, and to map potential contact zones between flying fox habitats, pig farms and human settlements, we conducted field observation, remote sensing, and ecological niche modeling to characterize flying fox colonies and their ecological neighborhoods. A Potential Surface Analysis was applied to map contact zones among local epizootic actors.

Results: Flying fox colonies are found mainly on Thailand's Central Plain, particularly in locations surrounded by bodies of water, vegetation, and safe havens such as Buddhist temples. High-risk areas for Nipah zoonosis in pigs include the agricultural ring around the Bangkok metropolitan region where the density of pig farms is high.

Conclusions: Passive and active surveillance programs should be prioritized around Bangkok, particularly on farms with low biosecurity, close to water, and/or on which orchards are concomitantly grown. Integration of human and animal health surveillance should be pursued in these same areas. Such proactive planning would help conserve flying fox colonies and should help prevent zoonotic transmission of Nipah and other pathogens.

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Related in: MedlinePlus

Study area of flying fox colonies. Study area covering 93,826.2 km2 of 23 provinces across western, central, and eastern Thailand (grey); 22 flying foxes’ colonies (red circles); comparing the size and locations of the study area and Thailand map (right).
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Fig1: Study area of flying fox colonies. Study area covering 93,826.2 km2 of 23 provinces across western, central, and eastern Thailand (grey); 22 flying foxes’ colonies (red circles); comparing the size and locations of the study area and Thailand map (right).

Mentions: The study area covered 23 provinces of western, central and eastern Thailand of a total area of 93,826 km2 (Figure 1). The distribution of flying foxes in central and eastern Thailand was studied in 2004 and 2011. Boonkird and Wanghongsa [25] surveyed the colony of flying foxes in central and eastern Thailand 2001–2004 and reported 16 sites in 10 provinces with 2 species of flying foxes: the Lyle’s flying fox (P. lylei) living in central Thailand and the Large flying fox or Greater flying fox (P. vampyrus) living along the coast of eastern Thailand. Sedsawai et al. [26] conducted a study of the distribution of flying foxes in central Thailand 2010–2011 and found 14 roosting sites within 10 provinces, including 10 previously reported and 4 newly discovered sites. Locations of bat colonies located in this area were obtained from these previous studies complemented by locations from field surveys by the Department of National Parks, Wildlife and Plant Conservation (DNP) conducted from March to August 2013. We surveyed each of those 22 bat colonies from June 2013 to January 2014 to verify the presence of flying foxes and to collect information on site characteristics for the roosting trees and their vicinities. We also estimated the margins of each colony with a hand-held GPS in order to delineate their spatial extent polygons.Figure 1


Spatial characterization of colonies of the flying fox bat, a carrier of Nipah virus in Thailand.

Thanapongtharm W, Linard C, Wiriyarat W, Chinsorn P, Kanchanasaka B, Xiao X, Biradar C, Wallace RG, Gilbert M - BMC Vet. Res. (2015)

Study area of flying fox colonies. Study area covering 93,826.2 km2 of 23 provinces across western, central, and eastern Thailand (grey); 22 flying foxes’ colonies (red circles); comparing the size and locations of the study area and Thailand map (right).
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4389713&req=5

Fig1: Study area of flying fox colonies. Study area covering 93,826.2 km2 of 23 provinces across western, central, and eastern Thailand (grey); 22 flying foxes’ colonies (red circles); comparing the size and locations of the study area and Thailand map (right).
Mentions: The study area covered 23 provinces of western, central and eastern Thailand of a total area of 93,826 km2 (Figure 1). The distribution of flying foxes in central and eastern Thailand was studied in 2004 and 2011. Boonkird and Wanghongsa [25] surveyed the colony of flying foxes in central and eastern Thailand 2001–2004 and reported 16 sites in 10 provinces with 2 species of flying foxes: the Lyle’s flying fox (P. lylei) living in central Thailand and the Large flying fox or Greater flying fox (P. vampyrus) living along the coast of eastern Thailand. Sedsawai et al. [26] conducted a study of the distribution of flying foxes in central Thailand 2010–2011 and found 14 roosting sites within 10 provinces, including 10 previously reported and 4 newly discovered sites. Locations of bat colonies located in this area were obtained from these previous studies complemented by locations from field surveys by the Department of National Parks, Wildlife and Plant Conservation (DNP) conducted from March to August 2013. We surveyed each of those 22 bat colonies from June 2013 to January 2014 to verify the presence of flying foxes and to collect information on site characteristics for the roosting trees and their vicinities. We also estimated the margins of each colony with a hand-held GPS in order to delineate their spatial extent polygons.Figure 1

Bottom Line: While no evidence of infection in domestic pigs or people has been found to date, pig farming is an active agricultural sector in Thailand and therefore could be a potential pathway for zoonotic disease transmission from the bat reservoirs.Flying fox colonies are found mainly on Thailand's Central Plain, particularly in locations surrounded by bodies of water, vegetation, and safe havens such as Buddhist temples.Such proactive planning would help conserve flying fox colonies and should help prevent zoonotic transmission of Nipah and other pathogens.

View Article: PubMed Central - PubMed

Affiliation: Department of Livestock Development (DLD), Bangkok, Thailand. weeraden@yahoo.com.

ABSTRACT

Background: A major reservoir of Nipah virus is believed to be the flying fox genus Pteropus, a fruit bat distributed across many of the world's tropical and sub-tropical areas. The emergence of the virus and its zoonotic transmission to livestock and humans have been linked to losses in the bat's habitat. Nipah has been identified in a number of indigenous flying fox populations in Thailand. While no evidence of infection in domestic pigs or people has been found to date, pig farming is an active agricultural sector in Thailand and therefore could be a potential pathway for zoonotic disease transmission from the bat reservoirs. The disease, then, represents a potential zoonotic risk. To characterize the spatial habitat of flying fox populations along Thailand's Central Plain, and to map potential contact zones between flying fox habitats, pig farms and human settlements, we conducted field observation, remote sensing, and ecological niche modeling to characterize flying fox colonies and their ecological neighborhoods. A Potential Surface Analysis was applied to map contact zones among local epizootic actors.

Results: Flying fox colonies are found mainly on Thailand's Central Plain, particularly in locations surrounded by bodies of water, vegetation, and safe havens such as Buddhist temples. High-risk areas for Nipah zoonosis in pigs include the agricultural ring around the Bangkok metropolitan region where the density of pig farms is high.

Conclusions: Passive and active surveillance programs should be prioritized around Bangkok, particularly on farms with low biosecurity, close to water, and/or on which orchards are concomitantly grown. Integration of human and animal health surveillance should be pursued in these same areas. Such proactive planning would help conserve flying fox colonies and should help prevent zoonotic transmission of Nipah and other pathogens.

Show MeSH
Related in: MedlinePlus