Human Sapovirus among Outpatients with Acute Gastroenteritis in Spain: A One-Year Study

Miguel F Varela,Jesús L Romalde,Enrique Rivadulla,Alberto Lema

doi:10.3390/v11020144

Abstract

Viral agents of human gastroenteritis affect people of all ages across the globe. As a mainly self-limiting disease, it is difficult to evaluate the real prevalence of etiological agents circulating in each region. Many of the analyzed outbreaks are caused by viruses of the family Caliciviridae, especially the genus Norovirus (NoV). Most studies have focused on other enteric viruses, leaving sapovirus (SaV) underestimated as an important emerging human threat. This one-year study analyzed clinical samples from hospital outpatients with acute gastroenteritis in Spain, with the aim of revealing the importance of human SaV as an emerging viral pathogen. A total of 2667 stools were tested using reverse transcription (RT)-qPCR to detect and quantify SaV. Sapovirus was detected in all age groups, especially in infants, children, and the elderly. The prevalence was 15.64% (417/2667), and was slightly higher in 0–2- and 3–5-year-olds (19.53% and 17.95%, respectively) and much lower in 13–18-year-olds (9.86%). Positive samples were detected throughout the year, with peaks of detection during autumn and the late winter to early spring months. The mean value for the quantified samples was 6.5 × 105 genome copies per gram of stool (GC/g) (range 2.4 × 103–6.6 × 1011 GC/g). RT-nested PCR and sequencing were used for further genotyping. Genetic characterization showed a predominance of genogroup I (GI), followed by GII and GIV. The detection of multiple genotypes suggests the circulation of different strains without any clear tendency. The results obtained suggest SaV as the second major gastroenteritis agent after NoV in the region.

Highlights

Foodborne diseases have been, during the last years, the eighth major cause of human deaths, becoming third on the African continent, and have been the cause of 9% of mortalities in children worldwide, according to the Global Health Observatory [1]
Genetic characterization showed a predominance of genogroup I (GI), followed by genogroup II (GII) and GIV
Enteric viruses are among the major contributors, including a wide range of etiological agents such as adenovirus (AdV), astrovirus, rotavirus (RV), aichivirus, sapovirus (SaV), hepatitis A and E virus, and norovirus (NoV)

Summary

Introduction

Foodborne diseases have been, during the last years, the eighth major cause of human deaths, becoming third on the African continent, and have been the cause of 9% of mortalities in children worldwide, according to the Global Health Observatory [1]. Enteric viruses are among the major contributors, including a wide range of etiological agents such as adenovirus (AdV), astrovirus, rotavirus (RV), aichivirus, sapovirus (SaV), hepatitis A and E virus, and norovirus (NoV). Most of them are considered foodborne viruses, but their transmission occurs via the ingestion of infected food and water (the irrigation of fruits and vegetables, and shellfish harvested in polluted waters), and via person-to-person contact (infected workers and handlers), contaminated environments, and fomites. They are characterized by low infectious doses and high levels of viral excretion [2]. SaV are classified into five genogroups, Viruses 2019, 11, 144; doi:10.3390/v11020144 www.mdpi.com/journal/viruses

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