Gastroenteritis In Thailand Research Articles

Unusual G3P[10] bat-like rotavirus strains detected in children with acute gastroenteritis in Thailand.

Rotavirus A (RVA) is the main cause of acute gastroenteritis among children under the age of five globally. The unusual bat-like human RVA strains G3P[10] (RVA/Human-wt/THA/CMH079/05/2005/G3P[10] and RVA/Human-wt/THA/CMH-S015-19/2019/G3P[10]) were detected in children with acute gastroenteritis in 2005 and 2019, respectively, in the same geographical area of Northern Thailand. To elucidate the genetic backgrounds of these unusual or bat-like human RVA strains, the complete genome of these RVA strains was sequenced and phylogenetically analyzed. All eleven genome segments of these G3P[10] strains were genotyped as G3-P[10]-I8-R3-C3-M3-A9-N3-T3-E3-H6, which is closely related to bat G3P[10] RVA strain (RVA/Bat-tc/CHN/MYAS33/2013/G3P[10]) and bat-like human RVA strain (RVA/Human-wt/THA/MS2015-1-0001/2015/G3P[10]). The findings indicate that human G3P[10] RVA strains detected in this study (RVA/Human-wt/THA/CMH079/05/2005/G3P[10] and RVA/Human-wt/THA/CMH-S015-19/2019/G3P[10]) contained all eleven genome segments similar to those of bat RVA strains and appeared to be human RVA strains of bat origin. Phylogenetic analysis revealed that several genome segments of these two RVA strains were also closely related with those of other species in addition to bats and had a zoonotic transmission history. The results of this study supported the roles of interspecies transmission of RVA strains among bats and humans in the natural environment and provided convincing evidence that the evolution of human RVAs was closely interrelated with those of animal RVAs. Continuing surveillance of RVAs in humans and animals is imperative to gain a better understanding of the origin and the evolution of these viruses.

Enterovirus genotype diversity with emergence of coxsackievirus A2 circulating in pediatric patients with acute gastroenteritis in Thailand, 2019-2022.

Enteroviruses (EVs) are recognized as potential causative agents of acute gastroenteritis (AGE) in children worldwide. This study aimed to investigate the epidemiology and molecular characteristics of EV infection in children admitted to hospitals with AGE in Chiang Mai, Thailand from 2019 to 2022. A total of 1,148 fecal samples collected from patients with AGE were screened for the presence of EV using RT-PCR. The prevalence, co-infection with common diarrheal viruses, and seasonal pattern of EV were examined. The genotypes of EV were identified based on the VP1 sequence and phylogenetic analysis. The overall prevalence of EV in AGE patients was 8.8% (101/1,148). After the COVID-19 outbreak in 2019, a significant decrease in the EV infection rate and genotype diversity was observed (p < 0.05). EV infection alone was observed in 68.3% (69/101) of cases while co-infection with other enteric viruses was 31.7% (32/101). The seasonal pattern of EV infection showed a peak prevalence during the rainy season. EV species A was the most prevalent (37.5%), followed by species B (32.3%), species C (29.2%), and species D (1.0%). Twenty-five genotypes of EV were identified with the most predominant of the coxsackievirus A2 (CV-A2) (13.5%), CV-B2 (7.3%) and CV-A24 (5.2%). Our data demonstrate a significant decrease in the prevalence and diversity of EV circulating in AGE patients during the COVID-19 pandemic and highlight the emergence of CV-A2 during this study period. These findings contribute to a better understanding of the molecular epidemiology and diversity of EV in patients with AGE and provide useful information for further investigation into the potential association between specific EV genotypes and AGE in future studies.

Genetic recombination and genotype diversity of norovirus GI in children with acute gastroenteritis in Thailand, 2015-2021

BackgroundHuman norovirus is a predominant etiological agent responsible for acute gastroenteritis across all age groups. Recently, norovirus recombinant strains have been reported as the cause of norovirus outbreaks in several settings and the strains that cause outbreaks mostly belong to the norovirus GII. However, yet, the norovirus GI recombinant strains have never been reported previously in Thailand. The aims of this study were to investigate the genetic recombination and genotype diversity of norovirus GI strains in children hospitalized with acute gastroenteritis in Chiang Mai, Thailand during a period of seven years from 2015 to 2021. MethodsA total of 2829 stool specimens were screened for norovirus GI by real-time PCR, and the polymerase and capsid genes were sequenced and analyzed. ResultsOf 2829 specimens tested, 12 (0.4%) were positive for norovirus GI. Of these, 7 out of 12 (58.3%) strains were identified as norovirus GI recombinant strains. Among 7 norovirus GI recombinant strains, 3, 3, and 1 were identified as GI.3[P13], GI.5[P4], and GI.6[P11], respectively. The remaining five strains were identified as non-recombinant strains of the GI.4[P4], GI.5[P5], and GI.6[P6] genotypes. ConclusionsThe findings highlight the genetic diversity and multiple intergenotype recombinant strains of norovirus GI circulating in children with acute gastroenteritis in Chiang Mai, Thailand from 2015 to 2021. The detection of multiple intergenotype norovirus GI recombinant strains further underscore the complexity of norovirus GI strains circulating in this region.

Distribution and molecular characterization of saffold virus and human cosavirus in children admitted to hospitals with acute gastroenteritis in Thailand, 2017-2022.

Saffold virus (SAFV) and human cosavirus (HCoSV) are emerging viruses of the Picornaviridae family. They have been shown to associate with gastrointestinal infection and more recently these viruses have also been demonstrated to associate with other clinical infections such as the respiratory tract, cardiovascular system, and the cerebral ventricular system. In this study, 2459 stool specimens collected from pediatric patients admitted to hospitals with acute gastroenteritis from January 2017 to December 2022, were screened for SAFV and HCoSV utilizing reverse transcription-polymerase chain reaction. Positive samples were then characterized into genotypes via nucleotide sequencing and bioinformatic analysis. Of the 2459 samples, 21 and 39 were positive for SAFV (0.9%) and HCoSV (1.6%), respectively. Three genotypes of SAFV were identified-SAFV-1 (38%), SAFV-2 (24%), and SAFV-3 (38%). Two genetic groups of HCoSV were identified-HCoSV-C (97%) and HCoSV-A (3%), demonstrating a large increase of HCoSV-C as compared to those reported previously from the same geographical region in Thailand. This study provides the prevalence of SAFV and HCoSV genotypes in Chiang Mai, Thailand during a period of 6 years from 2017 to 2022.

Diverse genotypes of human enteric and non-enteric adenoviruses circulating in children hospitalized with acute gastroenteritis in Thailand, from 2018 to 2021.

Human adenovirus (HAdV) is a common viral pathogen that causes diarrhea in children worldwide. The aim of this study was to investigate the prevalence and genotype diversity of HAdV strains circulating in children admitted to the hospitals with acute gastroenteritis (AGE) in Chiang Mai, Thailand, from 2018 to 2021. A total of 1,790 stool samples were screened for HAdV by PCR method, and 80 (4.5%) were positive for HAdV. Of these, children under 5 years of age accounted for 90.0% of HAdV-positive cases with the highest infection rate at the age group of 48-60 months old. The infection rate was not significantly different between boys and girls. The HAdV infection was detected sporadically throughout the year without a discrete seasonal pattern. Five species of both enteric and non-enteric HAdVs (A, B, C, E, and F) with 10 different genotypes, including HAdV-F41 (25.0%), HAdV-B3 (17.5%), HAdV-F40 (16.3%), HAdV-C1 (15.0%), HAdV-C5 (7.5%), HAdV-C2 (6.3%), HAdV-B7 (5.0%), HAdV-A12 (3.8%), HAdV-E4 (2.5%), and HAdV-B11 (1.3%), were detected in this study. In conclusion, our study reported the prevalence and seasonality of HAdV infection with a wide variety of HAdV genotypes circulating in children hospitalized with AGE during a period of 2018-2021 in Chiang Mai, Thailand. IMPORTANCE In the present study, the prevalence of human adenovirus (HAdV) infection in children with acute gastroenteritis (AGE) in Chiang Mai, Thailand, from 2018 to 2021 was detected at 4.5%. Diverse species and genotypes of HAdVs (HAdV-A12, HAdV-B3, HAdV-B7, HAdV-B11, HAdV-C1, HAdV-C2, HAdV-C5, HAdV-E4, HAdV-F40, and HAdV-F41) had been identified. The highest infection rate was found in children aged 48-60 months old. The HAdV infection was detected sporadically throughout the year. These findings imply that a wide variety of HAdV genotypes circulate in pediatric patients with AGE in Chiang Mai, Thailand.

Predominance of DS‐1‐like G8P[8] rotavirus reassortant strains in children hospitalized with acute gastroenteritis in Thailand, 2018–2020

AbstractRotavirus A (RVA) is an important cause of acute gastroenteritis (AGE) in children. This study aims to investigate the molecular epidemiology of RVA in children hospitalized with AGE in Chiang Rai, Thailand in 2018–2020 by reverse transcription polymerase chain reaction. Of 302 samples, RVA was detected in 11.6% (35 samples): 11.3% (19/168) in 2018–2019 and 11.9% (16/134) in 2019–2020. G8P[8] was the predominant genotype at 68.4% in 2018–2019 and 81.2% in 2019–2020. G1P[8] (15.8%), G2P[4] (5.3%), G3P[8] (10.5%) in 2018–2019, and G9P[8] (18.8%) in 2019–2020 were also detected. Whole‐genome analysis of G8P[8] revealed a DS‐1‐like genetic backbone: G8‐P[8]‐I2‐R2‐C2‐M2‐A2‐N2‐T2‐E2‐H2. Phylogenetically, the VP7 genes of G8P[8] clustered in a major lineage with previously published 51 DS‐1‐like G8P[8] reference strains, closely related to 13 G8P[8] strains from Thailand and China. These G8P[8] strains contained two unique amino acid substitutions (A125S and N147D) in the VP7 antigenic epitopes. In addition, the VP1 and NSP2 genes of G8P[8] clustered in lineages separated from the DS‐1‐like G8P[8] reference strains with a high genetic divergence but were closely related to G1P[8], G2P[4], G3P[8], or G9P[8]. Several amino acid differences were observed in the VP7 and VP8* antigenic epitopes of G8P[8] compared with RVA vaccine strains. Homology modeling confirmed that these different amino acid residues were located on the surface‐exposed area of the structure. Taken together, the genetic analysis clearly defines the Chiang Rai DS‐1‐like G8P[8] strains as a novel reassortant strain that might have evolved genetically through reassortment events and consequently received their VP1 and NSP2 genes from locally cocirculating‐RVA genotypes.

The emergence of recombinant norovirus GII.12[P16] and predominance of GII.3[P12] strains in pediatric patients with acute gastroenteritis in Thailand, 2019-2020.

Norovirus (NoV) and sapovirus (SaV) are important pathogens that cause acute gastroenteritis (AGE) in all age groups, commonly in children worldwide. Recently, a number of studies have reported a wide variety of NoV recombinant strains. This study aimed to investigate the distribution of NoV and SaV recombinant strains circulating in Chiang Mai, Thailand, during 2019-2020. One hundred and twenty-four NoV and seven SaV strains detected in children admitted to the hospital with AGE were included in this study. The partialRNA-dependent RNA-polymerase(RdRp)/VP1 regions of these NoV and SaV strains were analyzed by phylogenetic analysis, Simplot, and RDP software. Overall, eight recombination patterns of NoV were detected. NoV GII.4[P16] was the most common strain detected (39.1%), followed by GII.3[P12] (25.0%), GII.4[P31] (17.2%), and other recombinant strains were detected at a lower rate. NoV GII.12[P16] strains were detected for the first time in Thailand. For SaV, none of the recombinant strains was detected. All SaV strains, GI.1/GI.1, GI.2/GI.2, and GII.5/GII.5, exhibited VP1 genotype corresponded to RdRp genotype. In conclusion, this study demonstrates the distribution and diversity of NoV and SaV recombinant strains circulating in pediatric patients with AGE in Chiang Mai, during 2019-2020 with the emergence of NoV GII.3[P12] and GII.12[P16].

Emergence of Multiple Novel Inter-Genotype Recombinant Strains of Human Astroviruses Detected in Pediatric Patients With Acute Gastroenteritis in Thailand.

Objective: Human astrovirus (HAstV) is recognized as an important cause of acute gastroenteritis in children. Recombination between different genotypes of HAstV can contribute to diversity and evolution of the virus. This study aimed to investigate the emergence of HAstV recombinant strains in pediatric patients hospitalized with acute gastroenteritis in Chiang Mai, Thailand, spanning 2011–2020.Methods: A total of 92 archival HAstV strains collected from pediatric patients with acute gastroenteritis during 2011–2020 were further characterized to identify the recombinant strains. The ORF1b and ORF2 junction region of each strain was amplified and sequenced. The obtained sequences were analyzed in comparison with the reference sequences retrieved from GenBank database. Their genotypes were assigned using MEGA X software based on the partial ORF1b (RdRp) and ORF2 (capsid) regions, and the recombination breakpoints of recombinant strains were determined by SimPlot and RDP4 analyses.Results: Five inter-genotype recombinant strains with three recombination patterns of ORF1b/ORF2 of classic HAstV, HAstV8/HAstV1, HAstV8/HAstV3, and HAstV3/HAstV2, were detected. The recombination breakpoints of all strains were located at the 3′-end region of ORF1b close to the ORF1b/ORF2 junction.Conclusion: Several novel inter-genotype recombinant strains of classic HAstV genotypes were detected in pediatric patients with acute gastroenteritis in Chiang Mai, Thailand, during the period of 10 years from 2011 to 2020.

Epidemiology and genetic diversity of group A rotavirus in pediatric patients with acute gastroenteritis in Thailand, 2018-2019.

Group A rotaviruses (RVAs) are the major viruses that cause acute gastroenteritis in young children worldwide. The objective of this study was to investigate the prevalence and genotype diversity of RVAs circulating in children with acute gastroenteritis in Thailand in 2018-2019. A total of 1170 stool specimens were obtained from children admitted to hospitals with diarrhea and screened for RVAs by nested RT-PCR. The RVA genotypes were determined by multiplex-PCR or nucleotide sequencing and phylogenetic analysis. Out of 1170 stool specimens, 209 (17.9%) were positive for RVAs. The RVA G9P[8] genotype (24.4%) was the most dominant genotype, followed by G3P[8] (22.9%), G8P[8] (22.0%), G1P[8] (16.7%), G2P[4] (6.7%), G1P[6] (2.3%), G1P[4] (1.0%), G3P[4] (1.0%), G9P[4] (1.0%), mixed-infections of G1P[4] + G1P[8] (1.0%), and GXP[8] (0.5%). Moreover, an uncommon RVA G3P[10] genotype (0.5%), bearing bat-like VP7 and VP4 genes, was detected. This study reveals the prevalence and genetic diversity of RVA genotypes in children with acute gastroenteritis in Thailand. The knowledge obtained from this study is helpful for understanding the epidemiology of rotavirus in Thailand. The emergence of uncommon RVA strain G3P[10] provides an evidence for interspecies transmission of human and animal rotaviruses.

High prevalence of circulating DS-1-like human rotavirus A and genotype diversity in children with acute gastroenteritis in Thailand from 2016 to 2019.

BackgroundHuman rotavirus A (RVA) infection is the primary cause of acute gastroenteritis (AGE) in infants and young children worldwide, especially in children under 5 years of age and is a major public health problem causing severe diarrhea in children in Thailand. This study aimed to investigate the prevalence, genotype diversity, and molecular characterization of rotavirus infection circulating in children under 15 years of age diagnosed with AGE in Thailand from January 2016 to December 2019.MethodsA total of 2,001 stool samples were collected from children with gastroenteritis (neonates to children <15 years of age) and tested for RVA by real-time polymerase chain reaction (RT-PCR). Amplified products were sequenced and submitted to an online genotyping tool for analysis.ResultsOverall, 301 (15.0%) stool samples were positive for RVA. RVA occurred most frequently among children aged 0-24 months. The seasonal incidence of rotavirus infection occurred typically in Thailand during the winter months (December-March). The G3P[8] genotype was identified as the most prevalent genotype (33.2%, 100/301), followed by G8P[8] (10.6%, 32/301), G9P[8] (6.3%, 19/301), G2P[4] (6.0%, 18/301), and G1P[6] (5.3%, 16/301). Uncommon G and P combinations such as G9P[4], G2P[8], G3P[4] and G3P[9] were also detected at low frequencies. In terms of genetic backbone, the unusual DS-1-like G3P[8] was the most frequently detected (28.2%, 85/301), and the phylogenetic analysis demonstrated high nucleotide identity with unusual DS-1-like G3P[8] detected in Thailand and several countries.ConclusionsA genetic association between RVA isolates from Thailand and other countries ought to be investigated given the local and global dissemination of rotavirus as it is crucial for controlling viral gastroenteritis, and implications for the national vaccination programs.

Genomic characterization of a novel G3P[10] rotavirus strain from a diarrheic child in Thailand: Evidence for bat-to-human zoonotic transmission.

An unusual rotavirus strain with the G3P[10] genotype (RVA/Human-wt/THA/MS2015-1-0001/2015/G3P[10]) was identified in a stool sample from a hospitalized child aged 11months with severe gastroenteritis in Thailand. In the current study, we sequenced and characterized the full genome of strain MS2015-1-0001. On full-genomic analysis, strain MS2015-1-0001 exhibited the following genotype configuration: G3-P[10]-I8-R3-C3-M3-A9-N3-T3-E3-H6, which is identical or closely related to those of bat and bat-like rotavirus strains (MYAS33-like). Furthermore, phylogenetic analysis revealed that all 11 genes of strain MS2015-1-0001 appeared to be of bat origin. Our findings provide evidence for bat-to-human interspecies transmission of rotaviruses and important insights into dynamic interactions between human and bat rotavirus strains.

Genetic recombination and diversity of sapovirus in pediatric patients with acute gastroenteritis in Thailand, 2010-2018.

BackgroundHuman sapovirus (SaV) is an etiologic agent of acute gastroenteritis (AGE) in all age groups worldwide. Genetic recombination of SaV has been reported from many countries. So far, none of SaV recombinant strain has been reported from Thailand. This study examined the genetic recombination and genotype diversity of SaV in children hospitalized with AGE in Chiang Mai, Thailand.MethodsStool samples were collected from children suffering from diarrhea who admitted to the hospitals in Chiang Mai, Thailand between 2010 and 2018. SaV was detected by RT-PCR and the polymerase and capsid gene sequences were analysed.ResultsFrom a total of 3,057 samples tested, 50 (1.6%) were positive for SaV. Among positive samples, SaV genotype GI.1 was the most predominant genotype (40%; 20/50), followed by GII.1 and GII.5 (each of 16%; 8/50), GI.2 (14%; 7/50), GIV.1 (4%; 2/50), and GI.5 (2%; 1/50). In addition, 4 SaV recombinant strains of GII.1/GII.4 were identified in this study (8%; 4/50).ConclusionsThe data revealed the genetic diversity of SaV circulating in children with AGE in Chiang Mai, Thailand during 2010 to 2018 and the intragenogroup SaV recombinant strains were reported for the first time in Thailand.

High prevalence of equine-like G3P[8] rotavirus in children and adults with acute gastroenteritis in Thailand.

Group A rotavirus (RVA) is a major cause of acute gastroenteritis in infants and young children worldwide. This study aims to clarify the distribution of G/P types and genetic characteristics of RVAs circulating in Thailand. Between January 2014 and September 2016, 1867 stool specimens were collected from children and adults with acute gastroenteritis in six provinces in Thailand. RVAs were detected in 514/1867 (27.5%) stool specimens. G1P[8] (44.7%) was the most predominant genotype, followed by G3P[8] (33.7%), G2P[4] (11.5%), G8P[8] (7.0%), and G9P[8] (1.3%). Unusual G3P[9] (0.8%), G3P[10] (0.4%), G4P[6] (0.4%), and G10P[14] (0.2%) were also detected at low frequencies. The predominant genotype, G1P[8] (64.4%), in 2014 decreased to 6.1% in 2016. In contrast, the frequency of G3P[8] markedly increased from 5.5% in 2014 to 65.3% in 2015 and 89.8% in 2016. On polyacrylamide gel electrophoresis, most (135/140; 96.4%) of the G3P[8] strains exhibited a short RNA profile. Successful determination of the nucleotide sequences of the VP7 genes of 98 G3P[8] strains with a short RNA profile showed that they are all equine-like G3P[8] strains. On phylogenetic analysis of genome segments of two representative Thai equine-like G3P[8] strains, it was noteworthy that they possessed distinct NSP4 genes, one bovine-like and the other human-like. Thus, we found that characteristic equine-like G3P[8] strains with a short RNA electropherotype are becoming highly prevalent in children and adults in Thailand.

Molecular epidemiology and genetic diversity of human parechoviruses in children hospitalized with acute diarrhea in Thailand during 2011-2016

Little is known about human parechovirus (HPeV) infection in Thailand. The genotype distribution of HPeV strains in children admitted to hospitals with acute gastroenteritis was investigated using polymerase chain reaction (PCR) and nucleotide sequencing of the VP1 region as the detection and genotype identification methods, respectively. Of a total of 2,002 stool samples, 49 (2.4%) were positive for HPeV. Of these, HPeV-1 was the most predominant genotype (40.8%), followed by HPeV-3 (16.3%) and HPeV-14 (16.3%), while HPeV-5, -6, -2, -4, and -8 strains were less frequently detected, at 10.2%, 8.2%, 2%, 2%, and 2%, respectively. HPeV infections were detected throughout the year with the biannual peaks of infection in the rainy (Jun-Jul-Aug) and winter (Nov-Dec-Jan) months in Thailand. Based on VP1 amino acid sequence alignment, the arginyl-glycyl-aspartic acid (RGD) motif was found in HPeV-1, -2, -4, and -6 strains. Additionally, an amino acid insertion at the N-terminus of VP1 was observed in HPeV-4 and HPeV-5 strains. Phylogenetic analysis revealed that small clades of HPeV-1 and HPeV-3 strains emerged in 2016 and 2015, respectively, and dominated in the year of their emergence. The HPeV strains detected in Thailand in this study were most closely related to reference strains from Asia and Europe. The evolutionary rate of HPeV strains was 2.87 × 10-4 (95% highest posterior density (HPD) 0.10-6.14 × 10-4) substitutions/site/year. These findings provide information about the genetic diversity and evolutionary dynamics of HPeV genotypes circulating in pediatric patients with acute gastroenteritis in Thailand.

Molecular epidemiology of classic, MLB and VA astroviruses isolated from

This study aimed to investigate the molecular epidemiology and genetic diversity of astrovirus circulating in pediatric patients with acute gastroenteritis in Thailand. A total of 2034 fecal specimens collected between 2011 and 2016 from children hospitalized with acute gastroenteritis were analyzed for astrovirus infection using RT-PCR and nucleotide sequencing techniques. Overall, 54 samples were positive for astrovirus (2.6%). About half of the virus-positive samples (57.4%) were co-infection cases, mainly with rotavirus or norovirus. Genotyping revealed that three major clades, classic human astrovirus (HAstV) and newly emerging MLB and VA astroviruses co-circulated in the study population. At least seven different genotypes were identified and HAstV1 was the most predominant genotype detected (50%), followed by MLB1 (16.7%), HAstV4 (11.1%), HAstV5 and HAstV8 (7.4% each), MLB2 and VA2 (3.7% each). This study provided a useful information and contributed to molecular epidemiology of astroviruses including the novel MLB and VA astoviruses have been characterized and reported for the first time in Thailand.

Characterization of a G10P[14] rotavirus strain from a diarrheic child in Thailand: Evidence for bovine-to-human zoonotic transmission

An unusual rotavirus strain, DB2015-066 with the G10P[14] genotype (RVA/Human-wt/THA/DB2015-066/2015/G10P[14]), was detected in a stool sample from a child hospitalized with acute gastroenteritis in Thailand. Here, we sequenced and characterized the full-genome of the strain DB2015-066. On whole genomic analysis, strain DB2015-066 was shown to have a unique genotype constellation: G10-P[14]-I2-R2-C2-M2-A3-N2-T6-E2-H3. The backbone genes of this strain (I2-R2-C2-M2-A3-N2-T6-E2-H3) are commonly found in rotavirus strains from artiodactyls such as cattle. Furthermore, phylogenetic analysis indicated that each of the 11 genes of strain DB2015-066 could be of artiodactyl (likely bovine) origin. Thus, strain DB2015-066 appeared to be derived from through zoonotic transmission of a bovine rotavirus strain. Of note, the VP7 gene of strain DB2015-066 was located in G10 lineage-6 together with ones of bovine and bovine-like rotavirus strains, away from the clusters comprising other G10P[14] strains in G10 lineage-2/4/5/9, suggesting the occurrence of independent bovine-to-human interspecies transmission events. Our observations provide important insights into the origins of rare G10P[14] strains, and into dynamic interactions between artiodactyl and human rotavirus strains.

Increasing predominance of G8P[8] species A rotaviruses in children admitted to hospital with acute gastroenteritis in Thailand, 2010-2013.

Rotavirus A is a well-known etiological cause of acute gastroenteritis in infants and young children worldwide. In this study, we investigated the prevalence and distribution of RVA genotypes circulating in children with acute gastroenteritis in Thailand from 2010 to 2013. A total of 1,032 fecal specimens were collected from children with an age range from neonatal to 15 years of age and tested for RVA by RT-PCR. Of these, 184 (17.8%) were positive for RVA. The highest detection rate of RVA was found in children aged between 12 and 24 months. The G1P[8] genotype was identified as the most dominant genotype (57.6%), followed by G2P[4] (12.5%), G8P[8] (10.4%), G9P[8] (7.1%), G3P[8] (4.9%), G1P[4] (2.2%), G2P[8] (1.7%), and mixed-infections of G1 and G3 in combination with P[8] (0.5%). In addition, the uncommon human rotavirus strains G4P[6] (1.1%), G9P[19] (0.5%), G12P[4] (0.5%), and G12P[6] (0.5%) were also detected in this study. Interestingly, the unusual G8P[8] strains were detected at a relatively high frequency, and phylogenetic analysis revealed that these G8 strains were genetically closely related to bovine and bovine-like human G8 rotavirus strains reported previously from Thailand, Japan, Vietnam, India and Taiwan. These G8P[8] strains displayed the DS-1-like genotype constellation of G8-P[8]-I2-R2-C2-M2-A2-N2-T2-E2-H2 (in the order VP7-VP4-VP6-VP1-VP2-VP3-NSP1-NSP2-NSP3-NSP4-NSP5/6, respectively). Overall, the data indicated a high degree of diversity of RVA genotypes, with the emergence of several uncommon RVA strains in children with acute gastroenteritis in Thailand.

Emergence of G9P[8] rotaviruses in children with acute gastroenteritis in Thailand, 2015‐2016

Human group A rotavirus is a major contagious virus causing gastroenteritis in children. Molecular epidemiological study of group A rotavirus infections in hospitalized children was performed by multiplex RT-PCR during 2015-2016 in Chiang Rai, Thailand. G- and P-genotypes of positive rotavirus samples were further analyzed by one-step and two-step multiplex RT-PCR methods. Among 270 fecal specimens tested, rotavirus was the most prevalent (33.7%), followed by norovirus GII (4.1%), adenovirus (3%), and astrovirus (1.5%). Infection was common in patients aged 12-23 months (45.1%) and occurred mostly in children under 3 years of age (85.7%). The highest peak was in a hot month, March (64.8%). G9P[8] emerged as the most predominant (79.1%), followed by G3P[8] (13.2%), G1P[8] (3.3%), and mixed G-types (4.4%). Interestingly, Chiang Rai G9 strains were clustered within a distinct lineage VII including G9 recently reported since 2010-2015. G9-VII also contained four to five unique amino acid substitutions in the VP7 proteins compared with those of the G9 candidate vaccine strain RVA/Human-tc/IND/116E/1985/G9P[11] and the prototype RVA/Human-wt/USA/WI61/1983/G9P[8], defining the G9-VII as a novel variant. G3 strains were closely related to the "new G3P[8] reassortant variant" with an equine-like VP7 gene that emerged in several countries. This study contributes to the understanding of the genetic diversity, providing scientific support for future vaccine strategies to reduce the morbidity and mortality.

Multiple enterovirus genotypes circulating in children hospitalized with acute gastroenteritis in Thailand

Enterovirus (EV) infection is widespread and can lead to a broad range of clinical symptoms, from mild to severe forms of disease. EVs are not always classified as pathogen and the epidemiological surveillance of EV infection in acute gastroenteritis cases in Thailand remains unexplored. This study aims to investigate the frequency, seasonality and molecular characteristics of EV circulating in children hospitalized with acute gastroenteritis in Chiang Mai, Thailand from 2010 to 2014. A total of 1266 fecal samples were included in this study. RT-PCR amplification of the 5′UTR was used for EV screening and phylogenetic analysis of the VP1 sequence was performed for EV genotyping. EV was detected in 5.8% of infections (73 out of 1266). Based on VP1 sequence analysis, over half (50.8%) of the identified EV cases were caused by species C, and the next two most frequent were species B and A (35.4% and 13.8%, respectively). This study identified 28 different EV genotypes, EV-C96 and coxsackievirus A24 were the most frequent genotype detected (12.3% each). EV was detected throughout the year with an increase of detection rate in December–January and May–June. In conclusion, this study reported the prevalence of EV infection with a wide variety of EV genotypes in children with acute diarrhea.

Wide variety of recombinant strains of norovirus GII in pediatric patients hospitalized with acute gastroenteritis in Thailand during 2005 to 2015

Norovirus (NoV) has been reported as being a common cause of acute gastroenteritis both in children and adults worldwide. Of the many variants, NoV GII.4 is the most predominant genotype. One of the mechanisms that drives the evolution and emergence of new variants of NoV is homologous recombination. This study describes the genetic recombination involved in cases of NoV GII detected in pediatric patients with acute gastroenteritis in Chiang Mai, Thailand during 2005 to 2015. From a total of 1938 stool samples, 3 (0.15%) were positive for NoV GI and 298 (15.38%) were identified as NoV GII. The genotypes detected in this study were GI.6, GI.14, GII.1, GII.2, GII.3, GII.4, GII.6, GII.7, GII.12, GII.13, GII.14, GII.15, GII.16, GII.17, GII.20, and GII.21. The NoV recombinant strains were verified by analysis of the partial sequence of ORF1 (RdRp)/ORF2 (capsid) junction. Phylogenetic analyses of partial ORF1 and ORF2 regions resulted in the identification of 21 (6.98%) NoV recombinant strains. Among these, 9 recombination patterns were detected in this study; GII.Pe/GII.4, GII.Pg/GII.1, GII.Pg/GII.12, GII.P7/GII.6, GII.P7/GII.14, GII.P12/GII.4, GII.P16/GII.2, GII.P16/GII.13, and GII.P21/GII.3. The findings demonstrated the wide variety of recombinant strains of NoV GII strains detected in pediatric patients admitted to the hospitals with acute gastroenteritis in Chiang Mai, Thailand during the past decade.