BMC veterinary research · 2026
Genetic and biological characterization of H9N2 avian influenza viruses isolated from swine in China.
СтатьяНазвание и аннотация: Перевод в очереди
Обработка статьи · этапы, ошибки и управление
Загрузка состояния…
Ошибки и ограничения
История · было → стало
Состояние обновляется каждые 5 секунд, пока блок открыт. Процент показывается только там, где известен объём работы. Пауза останавливает продолжение этапа; текущий запрос к источнику может завершиться.
Zhao Yuzhong, Liu Chang, Li Yingchao, Wang Yu, Hou Bingyu, Gao Hongyan, Liu Zhong, Wu Xiaotong, Lu Man, Shen Yang, Yang Pingping, Yuan Hongjie, Hou Yanmeng, Xiao Yihong
Аннотация
BACKGROUND: H9N2 avian influenza virus (AIV) has been circulating in poultry in China for decades and are undergoing adaptation to mammals, posing potential pandemic risks. To investigate the prevalence of H9N2 AIVs in swine, we conducted surveillance in Shandong Province from 2021 to 2023.
RESULTS: Two H9N2 influenza virus strains, A/swine/Shandong/417/2021(Sw/SD/417/21) and A/swine/Shandong/662/2022 (Sw/SD/662/22), were successfully isolated from swine and genetically characterized. Phylogenetic analyses showed that both isolates were reassortants containing gene segments from multiple H9N2 AIV lineages and closely related to currently circulating H9N2 AIV. Key molecular marker analysis revealed that both isolates carried mammalian-adaptive residues in the HA receptor-binding sites (183 N, 190 V, 226 L), a novel HA cleavage site variant (PSKSSRGL), PB2 mutations (A588V, E627V), and the M2 S31N substitution, suggesting potential adaptation to mammalian hosts and resistance to adamantane antivirals. Mice infection experiments demonstrated efficient viral replication in the respiratory tract, particularly in the lungs, but only mild histopathological changes were observed, with no significant weight loss or mortality, indicating low pathogenicity in mice. Serological surveillance of 3,172 swine serum samples showed a low prevalence of H9N2 influenza virus infection (0.44%), with positive samples sporadically distributed across regions and years.
CONCLUSION: In summary, although H9N2 AIV infection in swine is rare and generally mild, the presence of mammalian-adaptive markers and reassortant genomes highlights the potential risk of cross-species transmission and subclinical adaptation. Continuous avian-swine-human influenza surveillance is therefore essential to mitigate the potential threat posed by H9N2 AIV.
RESULTS: Two H9N2 influenza virus strains, A/swine/Shandong/417/2021(Sw/SD/417/21) and A/swine/Shandong/662/2022 (Sw/SD/662/22), were successfully isolated from swine and genetically characterized. Phylogenetic analyses showed that both isolates were reassortants containing gene segments from multiple H9N2 AIV lineages and closely related to currently circulating H9N2 AIV. Key molecular marker analysis revealed that both isolates carried mammalian-adaptive residues in the HA receptor-binding sites (183 N, 190 V, 226 L), a novel HA cleavage site variant (PSKSSRGL), PB2 mutations (A588V, E627V), and the M2 S31N substitution, suggesting potential adaptation to mammalian hosts and resistance to adamantane antivirals. Mice infection experiments demonstrated efficient viral replication in the respiratory tract, particularly in the lungs, but only mild histopathological changes were observed, with no significant weight loss or mortality, indicating low pathogenicity in mice. Serological surveillance of 3,172 swine serum samples showed a low prevalence of H9N2 influenza virus infection (0.44%), with positive samples sporadically distributed across regions and years.
CONCLUSION: In summary, although H9N2 AIV infection in swine is rare and generally mild, the presence of mammalian-adaptive markers and reassortant genomes highlights the potential risk of cross-species transmission and subclinical adaptation. Continuous avian-swine-human influenza surveillance is therefore essential to mitigate the potential threat posed by H9N2 AIV.