Ahrens Ann Kathrin, Selinka Hans-Christoph, Wylezich Claudia, Wonnemann Hubert, Sindt Ole, Hellmer Hartmut H, Pfaff Florian, Höper Dirk, Mettenleiter Thomas C, Beer Martin, Harder Timm C
Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Greifswald-Isle of Riems, Germany.
Section II 1.4 Microbiological Risks, German Environment Agency (UBA), Berlin, Germany.
Microbiol Spectr. 2023 Jan 26;11(2):e0266422. doi: 10.1128/spectrum.02664-22.
Surveillance of avian influenza viruses (AIV) in wild water bird populations is important for early warning to protect poultry from incursions of high-pathogenicity (HP) AIV. Access to individual water birds is difficult and restricted and limits sampling depth. Here, we focused on environmental samples such as surface water, sediments, and environmentally deposited fresh avian feces as matrices for AIV detection. Enrichment of viral particles by ultrafiltration of 10-L surface water samples using Rexeed-25-A devices was validated using a bacteriophage ϕ6 internal control system, and AIV detection was attempted using real-time RT-PCR and virus isolation. While validation runs suggested an average enrichment of about 60-fold, lower values of 10 to 15 were observed for field water samples. In total 25/36 (60%) of water samples and 18/36 (50%) of corresponding sediment samples tested AIV positive. Samples were obtained from shallow water bodies in habitats with large numbers of waterfowl during an HPAIV epizootic. Although AIV RNA was detected in a substantial percentage of samples virus isolation failed. Virus loads in samples often were too low to allow further sub- and pathotyping. Similar results were obtained with environmentally deposited avian feces. Moreover, the spectrum of viruses detected by these active surveillance methods did not fully mirror an ongoing HPAIV epizootic among waterfowl as detected by passive surveillance, which, in terms of sensitivity, remains unsurpassed. Avian influenza viruses (AIV) have a wide host range in the avian metapopulation and, occasionally, transmission to humans also occurs. Surface water plays a particularly important role in the epidemiology of AIV, as the natural virus reservoir is found in aquatic wild birds. Environmental matrices comprising surface water, sediments, and avian fecal matter deposited in the environment were examined for their usefulness in AIV surveillance. Despite virus enrichment efforts, environmental samples regularly revealed very low virus loads, which hampered further sub- and pathotyping. Passive surveillance based on oral and cloacal swabs of diseased and dead wild birds remained unsurpassed with respect to sensitivity.
对野生水鸟种群中的禽流感病毒（AIV）进行监测对于早期预警以保护家禽免受高致病性（HP）AIV的入侵非常重要。获取个体水鸟样本困难且受限，限制了采样深度。在此，我们重点关注环境样本，如地表水、沉积物以及环境中沉积的新鲜禽粪，将其作为检测AIV的基质。使用Rexeed - 25 - A装置对10升地表水样本进行超滤以富集病毒颗粒，并使用噬菌体ϕ6内部控制系统进行验证，同时尝试使用实时RT - PCR和病毒分离技术检测AIV。虽然验证实验表明平均富集倍数约为60倍，但现场水样的富集倍数较低，仅为10至15倍。总共36份水样中有25份（60%）以及36份相应沉积物样本中有18份（50%）检测出AIV呈阳性。样本取自高致病性禽流感（HPAIV）流行期间水鸟数量众多的浅水体栖息地。尽管在相当比例的样本中检测到了AIV RNA，但病毒分离失败。样本中的病毒载量通常过低，无法进行进一步的亚型和致病型鉴定。环境中沉积的禽粪也得到了类似结果。此外，这些主动监测方法检测到的病毒谱并未完全反映被动监测所检测到的水鸟中正在发生的HPAIV流行情况，就敏感性而言，被动监测仍然是无与伦比的。禽流感病毒（AIV）在鸟类集合种群中有广泛的宿主范围，偶尔也会传播给人类。地表水在AIV的流行病学中起着特别重要的作用，因为天然病毒库存在于野生水鸟中。对包括地表水、沉积物以及环境中沉积的禽粪在内的环境基质在AIV监测中的实用性进行了研究。尽管进行了病毒富集工作，但环境样本中病毒载量通常很低，这阻碍了进一步的亚型和致病型鉴定。基于对患病和死亡野生鸟类口腔和泄殖腔拭子的被动监测在敏感性方面仍然是无与伦比的。
