Chutinimitkul Salin, Chieochansin Thaweesak, Payungporn Sunchai, Samransamruajkit Rujipat, Hiranras Thitikul, Theamboonlers Apiradee, Poovorawan Yong
Department of Pediatrics, Faculty of Medicine, Chulalongkorn University, Patumwan, Bangkok 10330, Thailand.
Virus Res. 2008 Mar;132(1-2):122-31. doi: 10.1016/j.virusres.2007.11.007. Epub 2007 Dec 21.
The annual influenza outbreaks can cause a high mortality rate among infants and children. In the tropics, influenza shows no clear dependence on seasons. In the present study, we performed molecular and phylogenetic analysis of H1N1 and H3N2 influenza virus isolated from infants and children diagnosed with respiratory tract illness between February 2006 and February 2007. A total of 33 samples (10.92%) were found positive for human influenza virus infection. Characterization of the hemagglutinin gene revealed conserved sequences at the receptor-binding site as well as variations due to amino acid substitutions at the antigenic site, potentially resulting in an N-linked glycosylation site. As for the neuraminidase gene, amino acid substitutions were found in N1 and N2 but not directly at the catalytic or framework sites of this enzyme. Based on the phylogenetic tree, the hemagglutinin 1 (HA1) region and the neuraminidase (NA) gene of both H1N1 and H3N2 isolated subtypes clustered with the current vaccine strain for the Northern Hemisphere 2007-2008. This finding contributes to understanding the evolution of influenza A viruses in humans and is useful for surveillance and vaccine strain selection.
每年的流感暴发可导致婴幼儿出现高死亡率。在热带地区，流感对季节没有明显的依赖性。在本研究中，我们对2006年2月至2007年2月期间从诊断为呼吸道疾病的婴幼儿中分离出的H1N1和H3N2流感病毒进行了分子和系统发育分析。共发现33份样本（10.92%）的人类流感病毒感染呈阳性。血凝素基因的特征显示，受体结合位点存在保守序列，同时抗原位点因氨基酸替换而出现变异，这可能导致一个N - 连接糖基化位点。至于神经氨酸酶基因，在N1和N2中发现了氨基酸替换，但并非直接出现在该酶的催化或框架位点。基于系统发育树，分离出的H1N1和H3N2亚型的血凝素1（HA1）区域和神经氨酸酶（NA）基因与2007 - 2008年北半球的当前疫苗株聚类。这一发现有助于了解甲型流感病毒在人类中的进化，对监测和疫苗株选择具有重要意义。
