Thanh Nguyen Thi Le, Vy Nguyen Ha Thao, Xuyen Huynh Thi Ai, Phuong Huynh Thi, Tuyet Phung Ngoc, Huy Nguyen Thanh, Nguyen-Van-Yen Benjamin, Lam Ha Minh, Boni Maciej F
Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, Ho Chi Minh City, Vietnam.
Ca Mau sub-Department of Livestock Prodution and Animal Health, Ward 5, Ca Mau City, Ca Mau, Vietnam.
PLoS Curr. 2017 May 5;9:ecurrents.outbreaks.c816d7333370d68f8a0da33f69168986. doi: 10.1371/currents.outbreaks.c816d7333370d68f8a0da33f69168986.
Subtype H5N1 avian influenza viruses, both high pathogenicity and low pathogenicity, have been enzootic in Vietnam since 2001. The viruses are readily identified at live bird markets, but virus prevalence on smallholder poultry is typically zero or very low. If the true direction of the viral transmission chain is farm to market, it is unknown why farm prevalence should be low when market prevalence is moderate to high.
We established a cohort of 50 smallholder poultry farms in Ca Mau province in the Mekong Delta region of Vietnam. From March 2016 to January 2017, we collected naso-pharyngeal and cloacal samples from 156 ducks and 96 chickens. In addition, 126 environmental samples were collected. Samples were assayed for H5 subtype influenza by real-time RT-PCR. Results/Discussion: None of the 378 collected samples were positive for H5 influenza. This is likely to mean that circulation of subtype H5 influenza viruses was low in Ca Mau in 2016. Detection of avian influenza on smallholder poultry farms is necessary to determine the directionality and association between farm prevalence and market prevalence of avian influenza viruses. Larger farm-level studies should be planned as these will be critical for determining the presence and strength of this association.
自2001年以来，高致病性和低致病性的H5N1亚型禽流感病毒在越南呈地方流行性。这些病毒在活禽市场很容易被识别，但小农户家禽中的病毒流行率通常为零或非常低。如果病毒传播链的真正方向是从农场到市场，那么当市场流行率为中度至高度时，农场流行率为何较低就不得而知了。
我们在越南湄公河三角洲地区的金瓯省建立了一个由50个小农户家禽养殖场组成的队列。从2016年3月到2017年1月，我们从156只鸭和96只鸡身上采集了鼻咽和泄殖腔样本。此外，还采集了126份环境样本。通过实时逆转录聚合酶链反应对样本进行H5亚型流感检测。结果/讨论：所采集的378份样本中没有一份H5流感呈阳性。这可能意味着2016年金瓯省H5亚型流感病毒的传播率较低。检测小农户家禽养殖场的禽流感对于确定禽流感病毒在农场的流行率和市场流行率之间的方向性和关联性是必要的。应规划更大规模的农场层面研究，因为这些研究对于确定这种关联的存在和强度至关重要。
