Abstract Title
Molecular surveillance for norovirus among children under 5 years of age with medically-attended acute gastroenteritis in Costa Rica, 2021-April 2025
Presenter
Mariel López, Inciensa
Co-Author(s)
Mariel López-Moya1, Estela Cordero-Laurent2, Francisco Duarte-Martínez2, Patricia Pérez-Herrera3, Marcela Hernández-de Mezerville3, Andrea Aguilar-Corrales3, Milena Arias-Jiménez3, Tatiana Moya-Moya3, Jorge Vargas Cousin3, Cendry Alfaro-Rojas3, Adriana Yock-Corrales3, Naomi Iihoshi4, Sara A. Mirza5, Jan Vinjé5
Abstract Category
Epidemology
Abstract
Background. There is very little information on the burden and genotype diversity of norovirus in medically-attended children under 5 years of age in Costa Rica.
Methods. In early 2021, 21 state hospitals and 7 private hospitals in Costa Rica were invited to submit stool or vomit specimens from children under 5 years of age with acute gastroenteritis (AGE) to the Enteric Virus Laboratory of the Costa Rican Institute for Research and Teaching in Nutrition and Health (INCIENSA) for GI and GII norovirus testing by Multiplex (TaqMan®) Real-time RT-PCR. Positive specimens were sequenced by whole genome sequencing (WGS) and genotyped by an online human calicivirus typing tool.
Results. During April 2021 and April 2025, 1,262 specimens were tested. Of these, 66.6 % (n= 840) were from children under two years of age, 43.3 % (n=547) were female and 67.6 % (n=853) resided in San José, the country's capital. Norovirus was detected in 223 specimens (17.7 %) of which 14 specimens were positive for GI norovirus and 209 specimens for GII norovirus. Among all positive specimens, 61.4 % (n=137) were successfully genotyped. The most frequently identified GII noroviruses were GII.4 Sydney[P16] (35.0%, n=48), GII.17[P17] (16.1%, n=22); GII.4 Wichita[P4] (13.1%, n=18), GII.4 Sydney[P12] (10.2%, n=14) and GII.4 San Francisco[P31] (8.0 %, n=11). Six specimens tested positive for GI norovirus and were typed as GI.5[P5] (2.2 %; n= 3), GI.3[P3] (0.7 %; n=1), GI.3[P13] (0.7 %; n=1) and GI.7[P7] (0.7 %; n=1).
Conclusions. Among specimens from Costa Rican children seeking medical care for AGE over a period of 4 years, 17.7 % tested positive for norovirus. The majority of specimens were from children under 2 years of age. Genogroup II noroviruses dominated, including GII.4 Sydney viruses and recently identified GII.4 Wichita and San Francisco as well as GII.17. GI viruses were identified with few detections. The implementation of molecular surveillance for norovirus provides insight on genotype diversity and will provide the Costa Rican Health Authorities with an accurate evidence base to make informed decisions for future norovirus prevention and control strategies.
Keywords: children, molecular surveillance, genotypes, norovirus
Methods. In early 2021, 21 state hospitals and 7 private hospitals in Costa Rica were invited to submit stool or vomit specimens from children under 5 years of age with acute gastroenteritis (AGE) to the Enteric Virus Laboratory of the Costa Rican Institute for Research and Teaching in Nutrition and Health (INCIENSA) for GI and GII norovirus testing by Multiplex (TaqMan®) Real-time RT-PCR. Positive specimens were sequenced by whole genome sequencing (WGS) and genotyped by an online human calicivirus typing tool.
Results. During April 2021 and April 2025, 1,262 specimens were tested. Of these, 66.6 % (n= 840) were from children under two years of age, 43.3 % (n=547) were female and 67.6 % (n=853) resided in San José, the country's capital. Norovirus was detected in 223 specimens (17.7 %) of which 14 specimens were positive for GI norovirus and 209 specimens for GII norovirus. Among all positive specimens, 61.4 % (n=137) were successfully genotyped. The most frequently identified GII noroviruses were GII.4 Sydney[P16] (35.0%, n=48), GII.17[P17] (16.1%, n=22); GII.4 Wichita[P4] (13.1%, n=18), GII.4 Sydney[P12] (10.2%, n=14) and GII.4 San Francisco[P31] (8.0 %, n=11). Six specimens tested positive for GI norovirus and were typed as GI.5[P5] (2.2 %; n= 3), GI.3[P3] (0.7 %; n=1), GI.3[P13] (0.7 %; n=1) and GI.7[P7] (0.7 %; n=1).
Conclusions. Among specimens from Costa Rican children seeking medical care for AGE over a period of 4 years, 17.7 % tested positive for norovirus. The majority of specimens were from children under 2 years of age. Genogroup II noroviruses dominated, including GII.4 Sydney viruses and recently identified GII.4 Wichita and San Francisco as well as GII.17. GI viruses were identified with few detections. The implementation of molecular surveillance for norovirus provides insight on genotype diversity and will provide the Costa Rican Health Authorities with an accurate evidence base to make informed decisions for future norovirus prevention and control strategies.
Keywords: children, molecular surveillance, genotypes, norovirus