Yin Xin, Wu Tiantian, Liu Shuo, Peng Cheng, Li Jinping, Mao Qiuyan, Zhang Yaxin, Zhou Shuning, Zhou Wanting, Hou Guangyu, Jiang Wenming, Liu Hualei
China Animal Health and Epidemiology Center, Qingdao, China.
Transbound Emerg Dis. 2024 Mar 5;2024:9923259. doi: 10.1155/2024/9923259. eCollection 2024.
The H3 influenza viruses are widespread in domestic poultry but have been ignored because their pathogenicity in poultry is low. Three human infections with H3N8 influenza viruses have been reported in China since 2022, raising public concern. Here, we comprehensively analyzed 30 H3 subtype avian influenza viruses isolated from live poultry markets in China between 2021 and 2022. Genetic and phylogenetic analyses showed that the H3 viruses have undergone frequent reassortment and have formed complex genotypes. Notably, the viruses that caused human infections in 2022-2023 were highly homologous to the H3N8 viruses circulating in poultry in 2022, with internal genes derived from the H9N2 viruses. The analysis of chicken infections indicated that the novel H3N8 viruses were more infectious in chickens than those that do not carry H9N2 genes, whereas the H3 viruses detected in China in 2021-2022 showed low pathogenicity in mice. Our findings suggest that the novel H3N8 viruses bearing internal H9N2 genes have adapted to and circulated in chickens and pose a threat to human health. These results highlight the need for continued surveillance of the H3 influenza viruses and their impact on the poultry industry.
H3型流感病毒在家禽中广泛传播，但因其在家禽中的致病性较低而被忽视。自2022年以来，中国已报告3例人感染H3N8流感病毒的病例，引起了公众关注。在此，我们全面分析了2021年至2022年间从中国活禽市场分离出的30株H3亚型禽流感病毒。遗传和系统发育分析表明，H3病毒频繁发生重配并形成了复杂的基因型。值得注意的是，2022-2023年导致人类感染的病毒与2022年在家禽中传播的H3N8病毒高度同源，其内部基因来源于H9N2病毒。对鸡感染情况的分析表明，新型H3N8病毒在鸡中的传染性高于不携带H9N2基因的病毒，而2021-2022年在中国检测到的H3病毒在小鼠中显示出低致病性。我们的研究结果表明，携带H9N2内部基因的新型H3N8病毒已适应在鸡群中传播，并对人类健康构成威胁。这些结果凸显了持续监测H3流感病毒及其对家禽业影响的必要性。
