Domestic Ducks and H5N1 Influenza Epidemic, Thailand

Songserm, Thaweesak; Jam-on, Rungroj; Sae-Heng, Numdee; Meemak, Noppadol; Hulse-Post, D. J.; Sturm‐Ramirez, Katharine; Webster, Robert G.

doi:10.3201/eid1204.051614

Cited by 172 publications

(157 citation statements)

References 17 publications

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“…The statistical relationship between ducks and HPAI H5N1 virus presence and the role of ducks as reservoir has been discussed elsewhere (10,14,(20)(21)(22). However, we found a strong and consistently positive association with rice cropping intensity across epidemic waves and countries.…”

Section: Discussionsupporting

confidence: 64%

Mapping H5N1 highly pathogenic avian influenza risk in Southeast Asia

Gilbert

Xiao

Pfeiffer

et al. 2008

Proc. Natl. Acad. Sci. U.S.A.

277

305

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The highly pathogenic avian influenza (HPAI) H5N1 virus that emerged in southern China in the mid-1990s has in recent years evolved into the first HPAI panzootic. In many countries where the virus was detected, the virus was successfully controlled, whereas other countries face periodic reoccurrence despite significant control efforts. A central question is to understand the factors favoring the continuing reoccurrence of the virus. The abundance of domestic ducks, in particular free-grazing ducks feeding in intensive rice cropping areas, has been identified as one such risk factor based on separate studies carried out in Thailand and Vietnam. In addition, recent extensive progress was made in the spatial prediction of rice cropping intensity obtained through satellite imagery processing. This article analyses the statistical association between the recorded HPAI H5N1 virus presence and a set of five key environmental variables comprising elevation, human population, chicken numbers, duck numbers, and rice cropping intensity for three synchronous epidemic waves in Thailand and Vietnam. A consistent pattern emerges suggesting risk to be associated with duck abundance, human population, and rice cropping intensity in contrast to a relatively low association with chicken numbers. A statistical risk model based on the second epidemic wave data in Thailand is found to maintain its predictive power when extrapolated to Vietnam, which supports its application to other countries with similar agro-ecological conditions such as Laos or Cambodia. The model's potential application to mapping HPAI H5N1 disease risk in Indonesia is discussed.animal husbandry ͉ epidemiology ͉ remote sensing ͉ spatial modeling

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Section: Discussionsupporting

confidence: 64%

Mapping H5N1 highly pathogenic avian influenza risk in Southeast Asia

Gilbert

Xiao

Pfeiffer

et al. 2008

Proc. Natl. Acad. Sci. U.S.A.

277

305

View full text Add to dashboard Cite

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“…However, the chance of this being the cause of natural resistance in our study is unlikely because our samples were obtained from the [2004][2005] epidemics when widespread use of OTV in poultry in Thailand did not occur. The infected poultry and free-grazing birds were culled to stop the spread of the virus (Songserm et al, 2006;Walker et al, 2012). Therefore, it is pertinent to investigate these naturally occurring mutations, and in this study the focus was on the genetic diversity found outside the NA drug-binding site of H5N1 viruses collected from naturally infected Asian open-billed storks during the outbreak in 2004 From our sequencing data, three dominant quasispecies, which are the S236F, the double and the quadruple mutants, were found.…”

Section: Discussionmentioning

confidence: 99%

The significance of naturally occurring neuraminidase quasispecies of H5N1 avian influenza virus on resistance to oseltamivir: a point of concern

Schaduangrat

Phanich

Rungrotmongkol

et al. 2016

Journal of General Virology

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Viral adaptability and survival arise due to the presence of quasispecies populations that are able to escape the immune response or produce drug-resistant variants. However, the presence of H5N1 virus with natural mutations acquired without any drug selection pressure poses a great threat. Cloacal samples collected from the 2004-2005 epidemics in Thailand from Asian open-billed storks revealed one major and several minor quasispecies populations with mutations on the oseltamivir (OTV)-binding site of the neuraminidase gene (NA) without prior exposure to a drug. Therefore, this study investigated the binding between the NA-containing novel mutations and OTV drug using molecular dynamic simulations and plaque inhibition assay. The results revealed that the mutant populations, S236F mutant, S236F/C278Y mutant, A250V/V266A/P271H/G285S mutant and C278Y mutant, had a lower binding affinity with OTV as compared with the WT virus due to rearrangement of amino acid residues and increased flexibility in the 150-loop. This result was further emphasized through the IC 50 values obtained for the major population and WT virus, 104.74 nM and 18.30 nM, respectively. Taken together, these data suggest that H5N1 viruses isolated from wild birds have already acquired OTV-resistant point mutations without any exposure to a drug.

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“…These results also suggested that post-harvest rice paddy fields, which are equally attractive to wild birds and poultry, may have actedas a meeting point between the two. With laboratory studies indicating that domestic ducks may develop HPAI H5N1 virus sub-clinical infections (Hulse-Post et al, 2005), the frequent movements of duck flocks, brought together in night shelters which are often located within villages, and from where live birds and eggs enter the market chain, made healthy ducks important potential virus transmitters and amplifiers of infection (Songserm et al, 2006).…”

Section: Introductionmentioning

confidence: 99%

Avian influenza, domestic ducks and rice agriculture in Thailand

Gilbert

Xiao

Chaitaweesub

et al. 2007

Agriculture, Ecosystems & Environment

118

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Highly pathogenic avian influenza (HPAI) caused by H5N1 viruses has become a global scale problem which first emerged in southern China and from there spread to other countries in Southeast and East Asia, where it was first confirmed in end 2003. In previous work, geospatial analyses demonstrated that free grazing ducks played critical role in the epidemiology of the disease in Thailand in the winter 2004/2005, both in terms of HPAI emergence and spread. This study explored the geographic association between free grazing duck census counts and current statistics on the spatial distribution of rice crops in Thailand, in particular the crop calendar of rice production. The analysis was carried out using both district level rice statistics and rice distribution data predicted with the aid of remote sensing, using a rice-detection algorithm. The results indicated a strong association between the number of free grazing ducks and the number of months during which second-crop rice harvest takes place, as well as with the rice crop intensity as predicted by remote sensing. These results confirmed that free grazing duck husbandry was strongly driven by agricultural land use and rice crop intensity, and that this later variable can be readily predicted using remote sensing. Analysis of rice cropping patterns may provide an indication of the location of populations of free grazing ducks in other countries with similar mixed duck and rice production systems and less detailed duck census data. Apart from free ranging ducks and rice cropping, the role of hydrology and seasonality of wetlands and water bodies in the HPAI risk analysis is also discussed in relation to the presumed dry season aggregation of wild waterfowl and aquatic poultry offering much scope for virus transmission.

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Domestic Ducks and H5N1 Influenza Epidemic, Thailand

Abstract: Traditional methods of raising ducks in Southeast Asia must be modified.

Cited by 172 publications

References 17 publications

Mapping H5N1 highly pathogenic avian influenza risk in Southeast Asia

Mapping H5N1 highly pathogenic avian influenza risk in Southeast Asia

The significance of naturally occurring neuraminidase quasispecies of H5N1 avian influenza virus on resistance to oseltamivir: a point of concern

Avian influenza, domestic ducks and rice agriculture in Thailand

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