Abstract Title
Genotypic distribution and molecular epidemiology of norovirus among under-five children hospitalized with acute gastroenteritis in South India, 2005-2020
Presenter
Tintu Varghese, Christian Medical College Vellore
Co-Author(s)
Tintu Varghese1 , Maheswari Kalaivanan1 , Sidhartha Giri1, Gagandeep Kang1
1 The Wellcome Trust Research Laboratory, Division of Gastrointestinal Sciences, Christian Medical College, Vellore, India
Abstract Category
Molecular Epidemiology & Evolution
Abstract
Background: A significant reduction in rotavirus diarrhea with the rotavirus vaccine introduction has shifted the focus to norovirus which accounts for approximately 15% of diarrheal hospitalization globally. The study aims to study the genotypic distribution of norovirus among under-five children in South India.
Methods : : Diarrheal stool samples were collected from under five children admitted with acute gastroenteritis at Christian Medical College, Vellore during 2005-2020. These samples were tested for norovirus GI and GII using real-time one-step RT-PCR targeting ORF1 and ORF2. Positive samples were amplified with RT-PCR and sequenced with sanger sequencing for genotyping. The phylogenetic analysis is in progress.
Results: Among the total of 4712 diarrheal samples collected during 2005-2020, 4346 (92.2%) samples were tested and 684 (15.7%) samples were norovirus positive.
36 (5.3%) were infected with norovirus GI, 644 (94.7%) were infected with GII genogroup and 4 (0.6%) samples had mixed infection with GI and GII. 449/684 (65.6%) strains were sequenced. 38 dual genotypes, 21 capsid types and 19 polymerase types were identified during the study period. G1.3 (56.7%) was the most common genotype among GI genogroup and GII.4 (59.9%) among GII genogroup. The most frequently detected dual genotypes were GII.4 Sydney [P16], GII.4[P4] and GII.3[P16]. The circulation of GII.4 variants reflected the global pattern with each variants seen emerging and circulating for a period of 2-3 years.
Conclusions: The systematic genomic surveillance of norovirus is essential to track circulating strains, identify new emerging variants, and provide baseline data for vaccine development.
Methods : : Diarrheal stool samples were collected from under five children admitted with acute gastroenteritis at Christian Medical College, Vellore during 2005-2020. These samples were tested for norovirus GI and GII using real-time one-step RT-PCR targeting ORF1 and ORF2. Positive samples were amplified with RT-PCR and sequenced with sanger sequencing for genotyping. The phylogenetic analysis is in progress.
Results: Among the total of 4712 diarrheal samples collected during 2005-2020, 4346 (92.2%) samples were tested and 684 (15.7%) samples were norovirus positive.
36 (5.3%) were infected with norovirus GI, 644 (94.7%) were infected with GII genogroup and 4 (0.6%) samples had mixed infection with GI and GII. 449/684 (65.6%) strains were sequenced. 38 dual genotypes, 21 capsid types and 19 polymerase types were identified during the study period. G1.3 (56.7%) was the most common genotype among GI genogroup and GII.4 (59.9%) among GII genogroup. The most frequently detected dual genotypes were GII.4 Sydney [P16], GII.4[P4] and GII.3[P16]. The circulation of GII.4 variants reflected the global pattern with each variants seen emerging and circulating for a period of 2-3 years.
Conclusions: The systematic genomic surveillance of norovirus is essential to track circulating strains, identify new emerging variants, and provide baseline data for vaccine development.