Sapovirus is now one of the primary causes of viral acute gastroenteritis, particularly due to the implementation of routine rotavirus vaccination. The authors were interested in the characteristics and impact of natural infection at the community level. They examined stool samples from 100 children randomly selected from a community-based birth cohort in Peru. All diarrhoeal stools and one non-diarrhoeal stool collected trimonthly from children up to 2 years of age (n=1669) were tested for sapovirus detection. If virus was detected then viral shedding duration was determined using additional weekly samples (n=440). The authors found that the incidence of sapovirus infection in the first and second year of life was 4.3 and 11.1 per 100-child months, respectively. By 2 years of age, 82% of children had had at least one sapovirus infection and 64% had had at least one sapovirus-associated diarrhoea episode. The median shedding period was found to be 18.5 days. In 112 out of 175 infections, 14 genotypes from four genogroups (GI, GII, GIV and GV) were identified. Among these genogroups, GI viruses were more frequently found in symptomatic than in asymptomatic infections (odds ratio [OR] 3.1, 95%CI 1.3-7.4). 59 children had serial sapovirus infections but only three had repeated infection of the same genotype. Therefore sapoviruses are a frequent cause of acute gastroenteritis in infants. Serial sapovirus infections by multiple genotypes suggest that genotype-specific immunity is provided by each infection.
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