Molecular epidemiology and host genetics of norovirus and rotavirus infections in Portuguese elderly living in aged care homes. Issue 6 (20th February 2019)

• Record Type: Journal Article
• Authors: Piedade, João; Nordgren, Johan; Esteves, Filipa; Esteves, Aida; Teodósio, Rosa; Svensson, Lennart; Istrate, Claudia
• Is Part Of: Journal of medical virology. Volume 91:Issue 6(2019)
• Page Start: 1014
• Page End: 1021
• Publication Date: 2019-02-20
• Subjects: elderly -- host genetics -- norovirus -- Portugal -- rotavirus; Virology -- Periodicals; 616
• DOI: 10.1002/jmv.25425
• Languages: English
• ISSNs: 0146-6615

Abstract

Abstract: 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. Highlights: Low detection rate of NoV/RVA infections in aged care facilities during 2 winter seasons RVA exclusively detected in asymptomatic elderly NoV GI.3 and GII.6 strains genotyped, the latter for the first time in Portugal The majority of NoV/RVA‐positive individuals were secretor‐positive, Lewis B phenotype All sequenced non‐secretors were homozygous for FUT2 nonsense mutation G428A.