Highly pathogenic avian influenza (H5N1) in ducks and in-contact chickens in backyard and smallholder commercial duck farms in Viet Nam

Henning, Joerg; Henning, Kate; Morton, John M.; Long, Nguyễn Thành; Ha, Nguyen Truc; Vu, Le T.; Vu, Pham P.; Hoa, Dong Manh; Meers, J.

doi:10.1016/j.prevetmed.2010.05.016

Cited by 50 publications

(53 citation statements)

References 30 publications

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“…On the other hand, we have detected strong H5 PCR-positive pools from healthy unvaccinated ducks, confirming again the potential role of H5N1 virus reservoirs in waterfowl [37,38] and providing evidence of failure in the indirect protection of the unvaccinated population with such a massvaccination strategy. Finally, this low virological prevalence measured on random samples at the farm level is in accord with another study conducted in the southern part of Vietnam a year before [39].…”

Section: Difficulties In Conferring High Herd Immunity Level With a Bsupporting

confidence: 88%

Evaluation of the vaccination efficacy against H5N1 in domestic poultry in the Red River Delta in Vietnam

et al. 2012

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SUMMARYThe domestic poultry population in Vietnam has been vaccinated against highly pathogenic avian influenza (HPAI) H5N1 since 2005. Since then, outbreaks have continued to occur without a clear understanding of the mechanisms involved. The general objective of this study was to understand the epidemiology of the disease in the context of vaccination and to draw some conclusions about vaccination efficacy in the domestic poultry population of the Red River Delta area. Five cross-sectional surveys to measure the serological and virological prevalence in vaccinated and unvaccinated poultry were performed from the end of 2008 to June 2010. The global seroprevalence was 24 % (95 % confidence interval 19 . 9-28 . 2). Determinants of vaccine immunogenicity were identified separately in chickens and ducks as well as determinants of the seroconversion in unvaccinated birds. The results highlight the difficulties in maintaining good flock immunity in poultry populations using inactivated vaccine in the field with two vaccination rounds per year, and in preventing circulation of virus in co-existing unvaccinated poultry.

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Section: Difficulties In Conferring High Herd Immunity Level With a Bsupporting

confidence: 88%

Evaluation of the vaccination efficacy against H5N1 in domestic poultry in the Red River Delta in Vietnam

et al. 2012

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“…A case-control study undertaken in Thailand at the subdistrict level found higher H5N1 infection rates for subdistricts with a high flock density of fighting cocks, quail and free-grazing ducks (Tiensin et al 2009). Henning et al (2011) conducted a longitudinal study across several farms in Vietnam, and found that seroprevalence peaks and seroprevalence troughs coincided with the most common harvest months and less frequent harvest months, respectively. Meanwhile, Pfeiffer (2007) suggested that domestic waterbirds and rice production are important for the maintenance and spread of infection.…”

Section: Free-grazing Poultrymentioning

confidence: 99%

“…A case-control study in the Red River Delta Region in Vietnam found that higher numbers of broiler flocks in the village increased the HPAI risk (Desvaux et al 2011). Moreover, vaccine efficacy under field conditions may change and may not reflect laboratory-based studies (Henning et al 2011). Finally, it is impossible to predict whether the currently circulating HPAI H5N1 will cause the next pandemic (Skeik and Jabr 2008).…”

Section: Future Pandemic Potentialmentioning

confidence: 99%

Persistence and transmission of avian influenza A (H5N1): virus movement, risk factors and pandemic potential

Tian

2015

Annals of GIS

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Repeated outbreaks in epidemic areas and invasion of new countries and regions expanded influence on poultry production, economics and the ecology of wild birds. Highly pathogenic avian influenza (HPAI) H5N1 has moved the world closer to a further global pandemic. An understanding of HPAI H5N1 transmission and persistence is therefore of significance for the prevention and control of epidemics. In this review we consider virus movement through poultry production systems (live bird markets, small holder farms and industry), wild bird migration and vector media (biological and mechanical); risk factors in poultry production systems (commercial, backyard and free-grazing farm); and the ecological environments (avian community, ecology and geographical isolation) of epidemic areas, and their effects on H5N1 virus transmission and persistence. We conclude that the pandemic potential, widespread transmission and sustained persistence of H5N1 is the result of conflicts between traditional production and consumption habits and the intense poultry production industry in Southeast Asia.

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“…While disposal of dead birds in open dumpsites and bushes can facilitate the dissemination of viruses (Musa et al, 2013;Spradbrow, 1993), feeding infected carcases to dogs may result in HPAI infection (Henning et al, 2011;Oluwayelu et al, 2011). Disposal of dead birds into water bodies can serve as sources of infection to humans particularly in rural communities where access to pipe borne water is limited.…”

Section: Survey Of Commercial and Backyard Poultry Farmersmentioning

confidence: 99%

Estimating the sensitivity of passive surveillance for HPAI H5N1 in Bayelsa state, Nigeria

Ojimelukwe

Prakarnkamanant

Rushton

2016

Preventive Veterinary Medicine

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Highly pathogenic avian influenza (H5N1) in ducks and in-contact chickens in backyard and smallholder commercial duck farms in Viet Nam

Cited by 50 publications

References 30 publications

Evaluation of the vaccination efficacy against H5N1 in domestic poultry in the Red River Delta in Vietnam

Evaluation of the vaccination efficacy against H5N1 in domestic poultry in the Red River Delta in Vietnam

Persistence and transmission of avian influenza A (H5N1): virus movement, risk factors and pandemic potential

Estimating the sensitivity of passive surveillance for HPAI H5N1 in Bayelsa state, Nigeria

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