Molecular Epidemiology of Human Sapovirus among Children with Acute Gastroenteritis in Western Canada

Abstract

Sapovirus is increasingly recognized as an important cause of acute gastroenteritis (AGE) worldwide; however, studies of sapovirus prevalence, genetic diversity, and strain-specific clinical implications have been scarce. To fill this knowledge gap, we used reverse transcription-real-time PCR and sequencing of the partial major capsid protein VP1 gene to analyze stool specimens and rectal swabs obtained from 3,347 children with AGE and 1,355 asymptomatic controls (all <18 years old) collected between December 2014 and August 2018 in Alberta, Canada. Sapovirus was identified in 9.5% (317/3347) of the children with AGE and 2.9% of controls. GI.1 (36%) was the predominant genotype identified, followed by GI.2 (18%), GII.5 (8%), and GII.3 (6%). Rare genotypes GII.1, GII.2, GV.1, GII.4, GIV.1, GI.3, and GI.7 were also seen. Sapovirus was detected year-round, peaking during the winter months of November to January. The exception was the 2016-2017 season, when GI.2 overtook GI.1 as the predominant strain, with a high detection rate persisting into April. We did not observe significant difference in the severity of gastroenteritis by genogroup or genotype. Repeated infection by sapovirus of different genogroups occurred in three controls who developed AGE later. Our data suggest that sapovirus is a common cause of AGE in children with high genetic diversity.

Keywords: genotype; pediatric gastroenteritis; repeated infection; sapovirus; seasonality.

FIG 1

Sapovirus testing results for study participants.

FIG 2

Monthly distribution of sapovirus genotypes in APPETITE children with acute gastroenteritis from January 2015 to July 2018. The percentages of cases infected with different genotypes normalized to the monthly total number of AGE cases are shown as stacked bars. The average monthly temperatures are shown as a smooth line.

FIG 3

Gastroenteritis severity by sapovirus genogroups, genotypes, or health care settings. MVS ≤ 8, mild; MVS = 9 to 10, moderate; MVS ≥ 11, severe. Cases without an MVS were excluded. (A) AGE severity attributed to different sapovirus genotypes. (B) AGE severity attributed to different sapovirus genogroups. (C) AGE severity in patients who seek ED care versus being managed at home. (D) AGE severity in different age groups.