Division of Global Health Protection, US Centers for Disease Control and Prevention, Village Market, Nairobi P.O. Box 606-00621, Kenya.
Paul G. Allen School for Global Health-Kenya, Washington State University, Nairobi P.O. Box 72938-00200, Kenya.
Viruses. 2024 Sep 5;16(9):1417. doi: 10.3390/v16091417.
Following the detection of highly pathogenic avian influenza (HPAI) virus in countries bordering Kenya to the west, we conducted surveillance among domestic and wild birds along the shores of Lake Victoria. In addition, between 2018 and 2020, we conducted surveillance among poultry and poultry workers in live bird markets and among wild migratory birds in various lakes that are resting sites during migration to assess introduction and circulation of avian influenza viruses in these populations. We tested 7464 specimens (oropharyngeal (OP) and cloacal specimens) from poultry and 6531 fresh fecal specimens from wild birds for influenza A viruses by real-time RT-PCR. Influenza was detected in 3.9% (n = 292) of specimens collected from poultry and 0.2% (n = 10) of fecal specimens from wild birds. On hemagglutinin subtyping, most of the influenza A positives from poultry (274/292, 93.8%) were H9. Of 34 H9 specimens randomly selected for further subtyping, all were H9N2. On phylogenetic analysis, these viruses were genetically similar to other H9 viruses detected in East Africa. Only two of the ten influenza A-positive specimens from the wild bird fecal specimens were successfully subtyped; sequencing analysis of one specimen collected in 2018 was identified as a low-pathogenicity avian influenza H5N2 virus of the Eurasian lineage, and the second specimen, collected in 2020, was subtyped as H11. A total of 18 OP and nasal specimens from poultry workers with acute respiratory illness (12%) were collected; none were positive for influenza A virus. We observed significant circulation of H9N2 influenza viruses in poultry in live bird markets in Kenya. During the same period, low-pathogenic H5N2 virus was detected in a fecal specimen collected in a site hosting a variety of migratory and resident birds. Although HPAI H5N8 was not detected in this survey, these results highlight the potential for the introduction and establishment of highly pathogenic avian influenza viruses in poultry populations and the associated risk of spillover to human populations.
在肯尼亚西部接壤的国家检测到高致病性禽流感 (HPAI) 病毒后，我们对维多利亚湖沿岸的家养和野生鸟类进行了监测。此外，在 2018 年至 2020 年期间，我们对活禽市场中的家禽和家禽工人以及在迁徙期间作为休息地的各种湖泊中的野生候鸟进行了监测，以评估这些人群中禽流感病毒的引入和传播情况。我们通过实时 RT-PCR 对来自家禽的 7464 份标本（口咽（OP）和泄殖腔标本）和来自野生鸟类的 6531 份新鲜粪便标本进行了流感 A 病毒检测。在采集的标本中，流感的检出率为 3.9%（n=292），在采集的野生鸟类粪便标本中为 0.2%（n=10）。在血凝素亚分型方面，来自家禽的大多数流感 A 阳性标本（274/292，93.8%）为 H9。随机选择 34 份 H9 标本进行进一步亚分型，均为 H9N2。系统进化分析表明，这些病毒与在东非检测到的其他 H9 病毒在基因上相似。从野生鸟类粪便标本中检测到的 10 份流感 A 阳性标本中只有 2 份成功进行了亚分型；对 2018 年采集的一个标本进行测序分析，鉴定为欧亚系低致病性禽流感 H5N2 病毒，第二个标本采集于 2020 年，鉴定为 H11。共采集了 18 份来自急性呼吸道疾病家禽工人的 OP 和鼻拭子（12%），均未检测到流感 A 病毒。我们观察到肯尼亚活禽市场中家禽中 H9N2 流感病毒的循环显著。在同一时期，在一个收容各种迁徙和留鸟的地点采集的粪便标本中检测到低致病性 H5N2 病毒。虽然本调查未检测到高致病性禽流感 H5N8，但这些结果突显了高致病性禽流感病毒在家禽群体中引入和建立的可能性，以及向人类群体溢出的相关风险。
