Mapping H5N1 highly pathogenic avian influenza risk in Southeast Asia

[Sally Furniss]

[SIZE=+2] Mapping H5N1 highly pathogenic avian influenza risk in Southeast Asia[/SIZE] <nobr>Marius Gilbert^*<sup>,

</sup></nobr>, <nobr>Xiangming Xiao<sup>

</sup></nobr>, <nobr>Dirk U. Pfeiffer<sup>

</sup></nobr>, <nobr>M. Epprecht^?</nobr>, <nobr>Stephen Boles<sup>

</sup></nobr>, <nobr>Christina Czarnecki<sup>

</sup></nobr>, <nobr>Prasit Chaitaweesub^||</nobr>, <nobr>Wantanee Kalpravidh^**</nobr>, <nobr>Phan Q. Minh<sup>

</sup></nobr>, <nobr>M. J. Otte<sup>

</sup></nobr>, <nobr>Vincent Martin<sup>

</sup></nobr>, and <nobr>Jan Slingenbergh<sup>

</sup></nobr>
*Biological Control and Spatial Ecology, Universit? Libre de Bruxelles, CP160/12, Avenue FD Roosevelt 50, B-1050 Brussels, Belgium; <sup>

</sup>Institute for the Study of Earth, Oceans, and Space, University of New Hampshire, 39 College Road, Durham, NH 03824; <sup>

</sup>Epidemiology Division, Department of Veterinary Clinical Sciences, The Royal Veterinary College, University of London, London AL9 7TA, United Kingdom; ^?Swiss National Center of Competence in Research North?South, 3012 Berne, Switzerland; ^||Department of Livestock Development, Ministry of Agriculture and Cooperatives, Bangkok 10400, Thailand; **Regional Office for Asia and the Pacific, Food and Agriculture Organization of the United Nations, Bangkok 10200, Thailand; <sup>

</sup>Department of Animal Health, Ministry of Agriculture and Rural Development, Hanoi, Vietnam; and <sup>

</sup>Food and Agriculture Organization of the United Nations, Viale delle Terme di Caracalla, 00100 Rome, Italy
Edited by Rita R. Colwell, University of Maryland, College Park, MD, and approved February 7, 2008 (received for review November 9, 2007)
[SIZE=+1]Abstract[/SIZE]
The highly pathogenic avian influenza (HPAI) H5N1 virus thatemerged in southern China in the mid-1990s has in recent yearsevolved into the first HPAI panzootic. In many countries wherethe virus was detected, the virus was successfully controlled,whereas other countries face periodic reoccurrence despite significantcontrol efforts. A central question is to understand the factorsfavoring the continuing reoccurrence of the virus. The abundanceof domestic ducks, in particular free-grazing ducks feedingin intensive rice cropping areas, has been identified as onesuch risk factor based on separate studies carried out in Thailandand Vietnam. In addition, recent extensive progress was madein the spatial prediction of rice cropping intensity obtainedthrough satellite imagery processing. This article analysesthe statistical association between the recorded HPAI H5N1 viruspresence and a set of five key environmental variables comprisingelevation, human population, chicken numbers, duck numbers,and rice cropping intensity for three synchronous epidemic wavesin Thailand and Vietnam. A consistent pattern emerges suggestingrisk to be associated with duck abundance, human population,and rice cropping intensity in contrast to a relatively lowassociation with chicken numbers. A statistical risk model basedon the second epidemic wave data in Thailand is found to maintainits predictive power when extrapolated to Vietnam, which supportsits application to other countries with similar agro-ecologicalconditions such as Laos or Cambodia. The model's potential applicationto mapping HPAI H5N1 disease risk in Indonesia is discussed.

http://www.pnas.org/cgi/content/abstract/0710581105v1?ct=ct