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

Abstract

iHuman 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-realtime PCR (qPCR) sapovirus was detected in 12.4% (37/299) of diarrheal and 5.7% (17/300) of nondiarrheal stools (P ‫؍‬ 0.004). The sapovirus AF (7.1%) was higher in the second year (13.2%) than in 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 a partial VP1 gene. Further sequence analysis of the full VP1 gene revealed a possible novel genotype, tentatively named GII.8. Notably, symptomatic reinfections with different genotypes within the same (n ‫؍‬ 3) or different (n ‫؍‬ 5) genogroups were observed in eight children. Sapovirus exhibited a 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. Acute diarrhea is one of the most important causes of morbidity and mortality in pediatric populations, especially in developing countries. Rotavirus, norovirus, and other viruses are common causative etiological agents, and rotavirus accounts for about 440,000 child deaths annually (1), while norovirus is a leading cause of epidemic and sporadic acute diarrhea (2). Currently a rotavirus vaccination program has been implemented in 80 countries as a part of national immunization programs (http://sites.path.org /rotavirusvaccine/rotavirus-vaccines/#global-intro). It successfully reduced the number of hospitalizations and deaths due to acute gastroenteritis (3, 4) and is cost-effective (5). Norovirus has now replaced rotavirus as the leading cause of medically attended acute diarrhea in pediatric populations (6, 7), and sapovirus, belonging to a separate genus of the Caliciviridae family, has been reported as the second most commonly detected virus after norovirus in children with acute diarrhea where rotavirus vaccination was implemented (8, 9). In addition, reports on sapovirus outbreaks across all age groups have increased in South Asia, Europe, and North America recently (10)(11)(12)(13)(14).The genome of sapovirus consists of a positive-sense, singlestranded RNA with two open reading frames (ORFs) (12). ORF1 encodes the nonstructural proteins and a major capsid protein, VP1, and ORF2 encodes a protein whose function is still unknown (12). Like for norovirus, multiple genetic clusters of human sapovirus have been reported, including four genogroups (GI, GII, GIV, and GV) with 17 gen...

Prevalence and genetic diversity of human sapovirus associated with sporadic acute gastroenteritis in South China from 2013 to 2017

“…In addition, GII.8 SaV is a recently identified genotype, which was also detected in our study. This genotype was detected only in the United States, Peru, and South Africa . Moreover, water environmental monitoring is also an important way to discover this new genotype .…”

Detection and genotyping of human adenovirus and sapovirus in children with acute gastroenteritis in Belém, Pará, between 1990 and 1992: first detection of GI.7 and GV.2 sapoviruses in Brazil

“…In addition, genotype GII.1 presents a high prevalence compared to other SaV genotypes. 34,35 . The first description of genotype GI.7 was made by analyzing all capsid proteins using universal primers for specific genogroups detected in samples from three prefectures (Chiba, Ehime, and Ishikawa) in Japan between 1999 and 2005 17 .…”

Broadly reactive real‐time reverse transcription‐polymerase chain reaction assay for the detection of human sapovirus genotypes

“…On the basis of the VP1 encoding nucleotide sequences, human sapoviruses are classified into four genogroups: GI, GII, GIV, and GV. GI, GII, and GV are currently each subdivided into seven, eight, and two genotypes (GI.1‐GI.7 and GII.1‐GII.8, and GV.1‐GV.2), whereas the GIV genogroup is less diverse and is thus placed into a single genotype (GIV.1) …”

“…This assay relied on the available near‐complete genome sequences, which correspond to the GI.1, GI.2, GI.3, GI.5 GII.1, GII.2, GII.3, GII.6, GIV.1, and GV.1 sapoviruses . This system has been used for detection of sapovirus from human stool specimens, shellfish, and environmental water samples . However, several sapovirus strains (classified as GI.2, GI.7, GII.7, GII.8, and GV.2) are poorly detected by this assay system (Mori et al, Oka et al, and Wu et al, unpublished results).…”

“…GI, GII, and GV are currently each subdivided into seven, eight, and two genotypes (GI.1-GI.7 and GII.1-GII.8, and GV.1-GV.2), whereas the GIV genogroup is less diverse and is thus placed into a single genotype (GIV.1). 1,3,7 A decade ago, a TaqMan probe-based real-time RT-PCR assay targeting the NS7-VP1 junction region of human sapovirus was developed for the detection of sapovirus strains belonging to the GI, GII, GIV, and GV genogroups. 8 This assay relied on the available nearcomplete genome sequences, which correspond to the GI.1, GI.2, GI.3, GI.5 GII.1, GII.2, GII.3, GII.6, GIV.1, and GV.1 sapoviruses.…”