Unidade de Microbiologia Médica, Global Health and Tropical Medicine (GHTM), Instituto de Higiene e Medicina Tropical (IHMT), Universidade NOVA de Lisboa (UNL), Lisboa, Portugal.
Department of Clinical and Experimental Medicine, Division of Molecular Virology, Medical Faculty, Linköping University, Linköping, Sweden.
J Med Virol. 2019 Jun;91(6):1014-1021. doi: 10.1002/jmv.25425. Epub 2019 Feb 20.
Norovirus (NoV) and rotavirus group A (RVA) are major agents of acute gastroenteritis worldwide. This study aimed to investigate their epidemiological profile in Portuguese elderly living in long-term care facilities and to assess the host genetic factors mediating infection susceptibility. From November 2013 to June 2015, 636 faecal specimens from 169 elderly, mainly asymptomatic, living in nursing homes in Greater Lisbon and Faro district, Portugal, were collected. NoV and RVA were detected by real-time polymerase chain reaction and NoV genotyped by phylogenetic analysis. NoV detection rate was 7.1% (12 of 169). Three GI.3 and one GII.6 strains were genotyped. RVA detection rate was 3.6% (6 of 169), exclusively in asymptomatic individuals. Host genetic factors associated with infection susceptibility were described on 250 samples by saliva-based enzyme-linked immunosorbent assays. The Lewis-negative phenotype was 8.8% (22 of 250) and the rate of nonsecretors was 16.8% (42 of 250). Association to NoV and RVA infection was performed in the subgroup of individuals (n = 147) who delivered both faecal and saliva samples. The majority of NoV- and RVA-positive individuals (90.9% and 83.3%, respectively) were secretor-positive, with Lewis B phenotype. In a subset of individuals, FUT2 and FUT3 genes were genotyped to assess mutations and validate the secretor and Lewis phenotypes. All sequenced nonsecretors were homozygous for FUT2 nonsense mutation G428A. In this study, low detection rates of NoV and RVA infections were found during two winter seasons. However, even in the absence of any outbreak, the importance of finding these infections in a nonepidemic situation in long-term care facilities may have important implications for infection control.
诺如病毒（NoV）和轮状病毒 A 型（RVA）是全球急性胃肠炎的主要病原体。本研究旨在调查葡萄牙长期护理机构中老年人的流行情况，并评估宿主遗传因素对感染易感性的影响。2013 年 11 月至 2015 年 6 月，采集了葡萄牙里斯本大都市区和法罗地区养老院 169 名主要无症状老年人的 636 份粪便标本。采用实时聚合酶链反应检测 NoV 和 RVA，通过系统进化分析对 NoV 进行基因分型。检测到的 NoV 检出率为 7.1%（169 例中的 12 例）。鉴定出 3 株 GI.3 和 1 株 GII.6 型。RVA 的检出率为 3.6%（169 例中的 6 例），均为无症状个体。通过基于唾液的酶联免疫吸附试验，在 250 例样本中描述了与感染易感性相关的宿主遗传因素。Lewis 阴性表型为 8.8%（250 例中的 22 例），非分泌者的比例为 16.8%（250 例中的 42 例）。在同时提供粪便和唾液样本的 147 名个体亚组中，对 NoV 和 RVA 感染进行了关联分析。大多数 NoV 和 RVA 阳性个体（分别为 90.9%和 83.3%）为 Lewis B 表型的分泌者。在个体亚组中，对 FUT2 和 FUT3 基因进行了基因分型，以评估突变并验证分泌者和 Lewis 表型。所有测序的非分泌者均为 FUT2 无义突变 G428A 的纯合子。在本研究中，两个冬季期间发现 NoV 和 RVA 感染的检出率较低。然而，即使在没有暴发的情况下，在长期护理机构的非流行情况下发现这些感染可能对感染控制具有重要意义。
