生鳥市場における高病原性鳥インフルエンザに対する衛生向上のためのリスク分析

本财政年度，我们重点进行了以下研究，以评估目前对活禽市场的干预措施，以将禽流感病毒(AIV)传播给家禽和人类的风险降至最低。比较了基础设施得到改善的活禽市场与越南常规运营的活禽市场的特点。这项研究表明，在有或没有干预的LBM监测过程中，分离出了不同亚型的AIV。此外，在其中一个干预措施中，从表面健康的鸭、番鸭和环境样品中分离到H5N6高致病性禽流感病毒(HPAIV)。干预组与非干预组AIV的患病率相似。这些结果表明，目前在越南中部地区LBM中应用的干预措施不足以控制禽流感。为了确定导致这两种LBM中AIV传播的因素，重点是量化禽类、家禽销售商和市场水平的特征，使个别禽类在销售时更有可能成为AIV分离阳性。结果表明，在市场和个体销售者层面上调整了聚集性后，问卷中的所有解释变量都没有与禽流感病毒阳性率显着相关。禽流感病毒阳性风险变化的一个相对较小的组成部分是在个人市场水平上。它表明，禽流感控制工作的重点应放在销售者层面，而不是市场层面。

This fiscal year, we focused on the following research to evaluate the current interventions on live bird market (LBM) in order to minimize the risk of avian influenza virus (AIV) transmission to poultry and humans.The characteristics of LBMs with improved infrastructure were compared with those operating in a routine manner in Vietnam. The study showed that various subtypes of AIVs were isolated during surveillance of LBMs with or without intervention. In addition, H5N6 highly pathogenic avian influenza viruses (HPAIVs) were isolated from apparently healthy ducks, Muscovy ducks and environmental samples in one of the intervention LBMs. And the prevalence of AIVs in intervention LBMs was similar to that in non-intervention LBMs. These results suggest that the interventions currently applied in LBMs in center part of Vietnam are insufficient to control avian influenza.To identify the factors contributing to AIVs circulation in both types of LBMs, this focused on quantification of bird-, poultry seller- and market-level characteristics that rendered individual birds more likely to be AIV isolation positive at the time of sale. The results demonstrate that after adjusting for clustering at the market- and individual seller-level none of the explanatory variables solicited in the questionnaire were significantly associated with AIV positivity. A relatively small component of the variation in AIV positivity risk was at the individual market-level. It indicates that the emphasis of avian influenza control efforts should be at the seller-level rather than market-level.