Molecular epidemiology and characterization of norovirus and sapovirus in pediatric patients with acute diarrhea in Thailand, 2019-2020

Background: Human enteric pathogens in the family Caliciviridae including norovirus (NoV) and sapovirus (SaV) are associated with acute diarrheal disease globally and are considered as one of the viruses with high genetic diversity.Methods: In order to investigate the epidemiology of NoV and SaV in pediatric patients with acute diarrhea in Chiang Mai, Thailand from January 2019 to December 2020, a total of 675 stool specimens were collected and examined for the presence of NoV and SaV by RT-multiplex PCR.Results: 126 (18.7 %) and 6 (0.9 %) stool samples were positive for NoV and SaV, respectively. Mixed in-fection of NoV and SaV was detected in one patient (0.2 %). Among 10 different NoV strains detected in this study, NoV genogroup II genotype 4 (GII.4) Sydney 2012 was the most predominant genotype (51.2 %) followed by GII.3, GII.2, GII.6, GII.12, GII.7, GII.17, GI.4, GII.14, and GI.3. Interestingly, monthly distribution of NoV genotypes revealed that NoV GII.3 increased dramatically in August 2019, suggesting an outbreak of NoV GII.3 might occur in the community. In addition, 3 genotypes of SaV were detected in this study with SaV GI.1 being the most common genotype (71.4 %) followed by GI.2 and GII.5 (each at 14.3 %).Conclusions: This study demonstrates the prevalence and genetic diversity of NoV and SaV circulating in pediatric patients with acute gastroenteritis in Chiang Mai, Thailand during 2019-2020 and shows an emergence of NoV GII.3 infection in 2019.(c) 2022 The Author(s). Published by Elsevier Ltd on behalf of King Saud Bin Abdulaziz University for Health Sciences. CC_BY_NC_ND_4.0

Automated summary

This study investigated the epidemiology of norovirus (NoV) and sapovirus (SaV) in pediatric patients with acute diarrhea in Chiang Mai, Thailand. The study found a positive detection rate of 18.7% for NoV and 0.9% for SaV, with one patient having a mixed infection of NoV and SaV. The most predominant genotype of NoV was NoV genogroup II genotype 4 (GII.4) Sydney 2012, while the most common genotype of SaV was GI.1. The study also identified a significant increase in NoV GII.3 infection in August 2019, suggesting an outbreak.