Genetic diversity of sapovirus in non-hospitalized adults with sporadic cases of acute gastroenteritis in Shanghai, China

BackgroundSapovirus has been accepted as a major cause of acute gastroenteritis worldwide. It can affect all age groups, ranging from young adults to the elderly, while little is known about the epidemiological patterns and genetic characteristics of sapovirus infections in China.ObjectivesTo investigate the prevalence of sapovirus infections among adult outpatients suffering from acute gastroenteritis in Shanghai, China.Study designFrom April 2011 to March 2013, fecal specimens from 1125 adult outpatients (≥16 years of age) with acute gastroenteritis were collected. Reverse transcription polymerase chain reaction (RT-PCR) was employed for detection of sapovirus, and 5′ end of capsid gene were sequenced for genotyping and phylogenetic analysis.ResultsThe overall occurrence of sapovirus infection in adult outpatients was 3.73% (42 in 1125) through the two-year surveillance period, and sapovirus diarrhea is more common in spring and winter. The highest sapovirus positive rate was observed in adults of ≥56 years old, and statistically significant relationship was observed when compared with other age groups (p < 0.05). Only three genotypes were detected, whereas GI.2 was proved to be the predominant strain, occupying 78.57% (33 in 42) of all strains, followed by GIV, GI.1 and GII.3.ConclusionsSapovirus was commonly found in adults with acute gastroenteritis in Shanghai, China, while no specific seasonal variation of sapovirus diarrhea could be distinguished. GI.2 strains established themselves in a short time span as the predominant genotype in Shanghai, China.