Rivas María José, Alegretti Miguel, Cóppola Leticia, Ramas Viviana, Chiparelli Héctor, Goñi Natalia
Centro Nacional de Referencia de Influenza, Unidad de Virología, Departamento de Laboratorios de Salud Pública, Ministerio de Salud, Montevideo 11600, Uruguay.
Departamento de Vigilancia en Salud, Ministerio de Salud, Montevideo 11200, Uruguay.
Microorganisms. 2020 Apr 19;8(4):591. doi: 10.3390/microorganisms8040591.
Influenza B viruses (IBV) are an important cause of morbidity and mortality during interpandemic periods in the human population. Two phylogenetically distinct IBV lineages, B/Yamagata and B/Victoria, co-circulate worldwide and they present challenges for vaccine strain selection. Until the present study, there was little information regarding the pattern of the circulating strains of IBV in Uruguay. A subset of positive influenza B samples from influenza-like illness (ILI) outpatients and severe acute respiratory illness (SARI) inpatients detected in sentinel hospitals in Uruguay during 2012-2019 were selected. The sequencing of the hemagglutinin (HA) and neuraminidase (NA) genes showed substitutions at the amino acid level. Phylogenetic analysis reveals the co-circulation of both lineages in almost all seasonal epidemics in Uruguay, and allows recognizing a lineage-level vaccine mismatch in approximately one-third of the seasons studied. The epidemiological results show that the proportion of IBV found in ILI was significantly higher than the observed in SARI cases across different groups of age (9.7% ILI, 3.2% SARI) and patients between 5-14 years constituted the majority (33%) of all influenza B infection ( < 0.05). Interestingly, we found that individuals >25 years were particularly vulnerable to Yamagata lineage infections.
乙型流感病毒（IBV）是人类大流行间期发病和死亡的重要原因。两种系统发育上不同的IBV谱系，即B/山形株和B/维多利亚株，在全球共同流行，这给疫苗株的选择带来了挑战。在本研究之前，关于乌拉圭IBV流行株模式的信息很少。选取了2012年至2019年期间在乌拉圭哨点医院检测到的流感样疾病（ILI）门诊患者和严重急性呼吸疾病（SARI）住院患者中乙型流感阳性样本的一个子集。血凝素（HA）和神经氨酸酶（NA）基因的测序显示在氨基酸水平上有替换。系统发育分析揭示了这两个谱系在乌拉圭几乎所有季节性流行中共同存在，并使得在大约三分之一的研究季节中识别出谱系水平的疫苗错配。流行病学结果表明，在不同年龄组中，ILI中发现的IBV比例显著高于SARI病例中的比例（ILI为9.7%，SARI为3.2%），5至14岁的患者占所有乙型流感感染的大多数（33%）（P<0.05）。有趣的是，我们发现25岁以上的个体特别容易感染山形株谱系。
