Department of Animal Health, Regional Animal Health Office Number 2, Haiphong 180000, Vietnam.
Faculty of Veterinary Medicine, Kasetsart University, Bangkok 10900, Thailand.
J Vet Sci. 2024 Mar;25(2):e20. doi: 10.4142/jvs.23184.
Avian influenza (AI) is a contagious disease that causes illness and death in poultry and humans. High pathogenicity AI (HPAI) H5N6 outbreaks commonly occur in Quang Ninh province bordering China. In June 2021, the first HPAI H5N8 outbreak occurred at a Quang Ninh chicken farm.
This study examined the risk factors associated with HPAI H5N6 and H5N8 outbreaks in Quang Ninh.
A retrospective case-control study was conducted in Quang Ninh from Nov 2021 to Jan 2022. The cases were households with susceptible poultry with two or more clinical signs and tested positive by real-time reverse transcription polymerase chain reaction. The controls were households in the same village as the cases but did not show clinical symptoms of the disease. Logistic regression models were constructed to assess the risk factors associated with HPAI outbreaks at the household level.
There were 38 cases with H5N6 clade 2.3.4.4h viruses (n = 35) and H5N8 clade 2.3.4.4b viruses (n = 3). Compared to the 112 controls, raising poultry in uncovered or partially covered ponds (odds ratio [OR], 7.52; 95% confidence interval [CI], 1.44-39.27), poultry traders visiting the farm (OR, 8.66; 95% CI, 2.7-27.69), farms with 50-2,000 birds (OR, 3.00; 95% CI, 1.06-8-51), and farms with ≥ 2,000 birds (OR, 11.35; 95% CI, 3.07-41.94) were significantly associated with HPAI outbreaks.
Combining biosecurity measures, such as restricting visitor entry and vaccination in farms with more than 50 birds, can enhance the control and prevention of HPAI in Quang Ninh and its spread across borders.
禽流感（AI）是一种传染性疾病，可导致家禽和人类患病和死亡。高致病性禽流感（HPAI）H5N6 疫情常在与中国接壤的广宁省爆发。2021 年 6 月，广宁省的一个养鸡场首次爆发 HPAI H5N8。
本研究旨在探讨与广宁省 HPAI H5N6 和 H5N8 疫情相关的危险因素。
2021 年 11 月至 2022 年 1 月期间，在广宁省进行了一项回顾性病例对照研究。病例组为有两种或多种临床症状且经实时逆转录聚合酶链反应检测呈阳性的易感家禽的家庭。对照组为与病例组同村但未出现疾病临床症状的家庭。采用 logistic 回归模型评估家庭层面与 HPAI 疫情相关的危险因素。
有 38 户家庭饲养的禽鸟感染了 H5N6 分支 2.3.4.4h 病毒（n=35）和 H5N8 分支 2.3.4.4b 病毒（n=3）。与 112 名对照相比，在未覆盖或部分覆盖的池塘中饲养家禽（比值比 [OR]，7.52；95%置信区间 [CI]，1.44-39.27）、有家禽交易商访问农场（OR，8.66；95%CI，2.7-27.69）、有 50-2000 只禽鸟的农场（OR，3.00；95%CI，1.06-8-51）和有≥2000 只禽鸟的农场（OR，11.35；95%CI，3.07-41.94）与 HPAI 疫情显著相关。
结合生物安全措施，如限制访客进入和对超过 50 只禽鸟的农场进行疫苗接种，可以加强广宁省 HPAI 的控制和预防，并防止其跨境传播。
