Etiological Role and Repeated Infections of Sapovirus among Children Aged Less than 2 Years in a Cohort Study in a Peri-urban Community of Peru

Human sapovirus has been shown to be one of the most important etiologies in pediatric patients with acute diarrhea. However, very limited data are available about the causative roles and epidemiology of sapovirus in community settings. A nested matched case-control study within a birth cohort study of acute diarrhea in a peri-urban community in Peru from 2007 to 2010 was conducted to investigate the attributable fraction (AF) and genetic diversity of sapovirus. By quantitative reverse transcription real-time polymerase chain reaction (RT-qPCR), sapovirus was detected in 12.4% (37/299) of diarrheal and 5.7% (17/300) of non-diarrheal stools (p=0.004). Sapovirus AF (7.1%) was higher in the second (13.2%) than the first year (1.4%) of life of children. Ten known genotypes and one novel cluster (n=5) within four genogroups (GI, GII, GIV and GV) were identified by phylogenetic analysis of partial VP1 gene. Further sequence analysis of full VP1 gene revealed a possible novel genotype, tentatively named as GII.8. Notably, symptomatic reinfections with different genotypes within the same (n=3) or different genogroups (n=5) were observed in eight children. Sapovirus exhibited high attributable burden for acute gastroenteritis especially in the second year of life of children in a Peruvian community. Further large-scale studies are needed to understand better the global burden, genetic diversity, and repeated infections of sapovirus.