Mohamed Wessam, Ito Kimihito, Omori Ryosuke
Division of Bioinformatics, Research Center for Zoonosis Control, Hokkaido University, Sapporo, Japan.
Front Microbiol. 2019 Dec 3;10:2765. doi: 10.3389/fmicb.2019.02765. eCollection 2019.
In 2014 and 2015, the number of human cases of H5N1 avian influenza virus infections had increased dramatically in Egypt. This increase might be related to increase in the transmission potential of the virus among humans. To clarify the cause of the increase in H5N1 human cases, we investigate the transmissibility of H5N1 viruses among humans via estimating the basic reproduction number using nucleotide sequences and sampling dates of viruses. To this end, full-length hemagglutinin gene sequences of human and avian H5N1 influenza viruses isolated from 2006 to 2016 in Egypt were obtained from the NCBI influenza virus resource. Taking into account the phylogeny, genetic distance, sampling time difference among viruses, was estimated to be 0.05 (95% CI: 0.01, 0.13) assuming that human-to-human transmissions occurred within a city, 0.23(95% CI: 0.14, 0.35) assuming human-to-human transmissions among cities. Our results indicate that human-to-human transmission of H5N1 viruses in Egypt is limited, and the large increase in human cases is likely attributed to other factor than increase in human-to-human transmission potential.
2014年和2015年，埃及H5N1禽流感病毒感染的人间病例数急剧增加。这种增加可能与该病毒在人间的传播潜力增加有关。为了阐明H5N1人间病例增加的原因，我们通过利用病毒的核苷酸序列和采样日期估计基本再生数，来研究H5N1病毒在人间的传播性。为此，从NCBI流感病毒资源库获取了2006年至2016年在埃及分离的人源和禽源H5N1流感病毒的全长血凝素基因序列。考虑到病毒之间的系统发育、遗传距离、采样时间差异，假设在一个城市内发生人际传播，估计(R_0)为0.05（95%置信区间：0.01，0.13）；假设在城市间发生人际传播，估计(R_0)为0.23（95%置信区间：0.14，0.35）。我们的结果表明，埃及H5N1病毒的人际传播是有限的，人间病例的大幅增加可能归因于人际传播潜力增加以外的其他因素。
