waybomb
Well-known member
ROME ― Ducks, people and rice paddies ― not chickens ― are the factors leading to outbreaks of the H5N1 strain of highly pathogenic avian influenza in Thailand and Viet Nam, and are probably behind outbreak persistence in other countries of the region such as Cambodia and Lao PDR.
"Mapping H5N1 highly pathogenic avian influenza risk in Southeast Asia: ducks, rice and people" was recently published in the latest issue of the Proceedings of the National Academy of Sciences of the United States. In the report a group of experts from the Foreign Agriculture Organization of the United Nations and associated research centers looked at the series of waves of H5N1 highly pathogenic avian influenza in Thailand and Viet Nam between early 2004 and late 2005.
Initiated and coordinated by F.A.O. senior veterinary officer Jan Slingenbergh, the researchers applied a modeling technique to establish how different factors contributed to the spread of the virus, including the numbers of ducks, geese and chickens, human population size, rice cultivation and local geography. The numbers of ducks and people, and the extent of rice cultivation emerged as the most significant factors, even though the two countries had fought outbreaks in two different ways.
The paper noted that there is a strong link between duck grazing patterns and rice cropping intensity. Ducks feed mainly on leftover rice grains in harvested paddy fields, so free-ranging ducks in both countries move to many different sites in line with rice harvest patterns,
"We now know much better where and when to expect H5N1 flare-ups, and this helps to target prevention and control. In addition, with virus persistence becoming increasingly confined to areas with intensive rice-duck agriculture in eastern and southeastern Asia, evolution of the H5N1 virus may become easier to predict," said Mr. Slingenbergh.
Interventions based on knowledge of hotspots and local rice-duck calendars is called for, in order to target disease control and replace indiscriminate mass vaccination, according to Mr. Slingenbergh.
"Mapping H5N1 highly pathogenic avian influenza risk in Southeast Asia: ducks, rice and people" was recently published in the latest issue of the Proceedings of the National Academy of Sciences of the United States. In the report a group of experts from the Foreign Agriculture Organization of the United Nations and associated research centers looked at the series of waves of H5N1 highly pathogenic avian influenza in Thailand and Viet Nam between early 2004 and late 2005.
Initiated and coordinated by F.A.O. senior veterinary officer Jan Slingenbergh, the researchers applied a modeling technique to establish how different factors contributed to the spread of the virus, including the numbers of ducks, geese and chickens, human population size, rice cultivation and local geography. The numbers of ducks and people, and the extent of rice cultivation emerged as the most significant factors, even though the two countries had fought outbreaks in two different ways.
The paper noted that there is a strong link between duck grazing patterns and rice cropping intensity. Ducks feed mainly on leftover rice grains in harvested paddy fields, so free-ranging ducks in both countries move to many different sites in line with rice harvest patterns,
"We now know much better where and when to expect H5N1 flare-ups, and this helps to target prevention and control. In addition, with virus persistence becoming increasingly confined to areas with intensive rice-duck agriculture in eastern and southeastern Asia, evolution of the H5N1 virus may become easier to predict," said Mr. Slingenbergh.
Interventions based on knowledge of hotspots and local rice-duck calendars is called for, in order to target disease control and replace indiscriminate mass vaccination, according to Mr. Slingenbergh.