Epidemiology of Enterovirus Genotypes in Association with Human Diseases.

Enteroviruses (EVs) are well-known causes of a wide range of infectious diseases in infants and young children, ranging from mild illnesses to severe conditions, depending on the virus genotypes and the host's immunity. Recent advances in molecular surveillance and genotyping tools have identified over 116 different human EV genotypes from various types of clinical samples. However, the current knowledge about most of these genotypes, except for those of well-known genotypes like EV-A71 and EV-D68, is still limited due to a lack of comprehensive EV surveillance systems. This limited information makes it difficult to understand the true burden of EV-related diseases globally. Furthermore, the specific EV genotype associated with diseases varies according to country, population group, and study period. The same genotype can exhibit different epidemiological features in different areas. By integrating the data from established EV surveillance systems in the USA, Europe, Japan, and China, in combination with other EV infection studies, we can elaborate a better understanding of the distribution of prevalent EV genotypes and the diseases associated with EV. This review analyzed the data from various EV surveillance databases and explored the EV seroprevalence and the association of specific EV genotypes with human diseases.

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

Introduction: 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. Methods: 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. Results: 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%). Conclusion: 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.

Diverse genotypes of norovirus genogroup I and II contamination in environmental water in Thailand during the COVID-19 outbreak from 2020 to 2022.

Noroviruses (NoVs) are the most significant viral pathogens associated with waterborne and foodborne outbreaks of nonbacterial acute gastroenteritis in humans worldwide. This study aimed to investigate the prevalence and diversity of NoVs contaminated in the environmental water in Chiang Mai, Thailand. A total of 600 environmental water samples were collected from ten sampling sites in Chiang Mai from July 2020 to December 2022. The presence of NoV genogroups I (GI), GII, and GIV were examined using real-time RT-PCR assay. The genotype of the virus was determined by nucleotide sequencing and phylogenetic analysis. The results showed that NoV GI and GII were detected at 8.5% (51/600) and 11.7% (70/600) of the samples tested, respectively. However, NoV GIV was not detected in this study. NoV circulated throughout the year, with a higher detection rate during the winter season. Six NoV GI genotypes (GI.1-GI.6) and eight NoV GII genotypes (GII.2, GII.3, GII.7, GII.8, GII.10, GII.13, GII.17, and GII.21) were identified. Among 121 NoV strains detected, GII.17 was the most predominant genotype (24.8%, 30 strains), followed by GII.2 (21.5%, 26 strains), GI.3 (17.4%, 21 strains), and GI.4 (16.5%, 20 strains). Notably, NoV GII.3, GII.7, GII.8, and GII.10 were detected for the first time in water samples in this area. This study provides insight into the occurrence and seasonal pattern of NoV along with novel findings of NoV strains in environmental water in Thailand during the COVID-19 outbreak. Our findings emphasize the importance of further surveillance studies to monitor viral contamination in environmental water.

Evaluation of a novel triplex immunochromatographic test for rapid simultaneous detection of norovirus, rotavirus, and adenovirus on a single strip test.

BACKGROUND: Acute gastroenteritis is one of the major causes of morbidity and mortality in young children worldwide. Among these, rotavirus, norovirus, and adenovirus have been reported as the primary viral pathogens associated with the disease. Rapid diagnosis of viral pathogens is crucial when diarrhea outbreaks occur to ensure the timely administration of appropriate treatment and control measures. METHODS: We evaluated three immunochromatographic test kits designed for the detection of norovirus, rotavirus, and adenovirus in 71 stool specimens collected from children with diarrhea who visited clinics in Japan. The first kit is a triplex immunochromatographic test kit designed for simultaneous detections of norovirus, rotavirus, and adenovirus on a single strip (this kit was referred to as IC-A). The other two immunochromatographic test kits are a dual detection kit for rotavirus and adenovirus, and a single detection kit for norovirus (IC-B). The RT-PCR/PCR was used as the gold standard method. RESULTS: The results revealed that both IC-A and IC-B kits exhibited the same level of sensitivity of detection for rotavirus (72.7%) and adenovirus (22.7%), although the detection rate was lower than that of the RT-PCR/PCR method. However, there was a slight difference in the sensitivity of detection for norovirus between IC-A and IC-B, at 86.7% and 93.3%, respectively. The sensitivity of detection for adenovirus of both kits was relatively lower than those of RT-PCR method. This could be due to low viral load of adenovirus in clinical specimens below the detection limit of IC-A and IC-B kits. However, both immunochromatographic test kits (IC-A and IC-B) exhibited 100% specificity for norovirus, rotavirus, and adenovirus. CONCLUSIONS: The triplex immunochromatographic test kit (IC-A) designed for simultaneous detection of norovirus, rotavirus, and adenovirus has been proved to be more practical and convenient than the use of single or dual detection kits with more or less the same sensitivity and specificity of detections.

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

BACKGROUND: Human 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. METHODS: A total of 2829 stool specimens were screened for norovirus GI by real-time PCR, and the polymerase and capsid genes were sequenced and analyzed. RESULTS: Of 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. CONCLUSIONS: The 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.

Hepatitis B virus genotypes associated with pregnant women in Northern Thailand.

BACKGROUND: Mother-to-child transmission of hepatitis B virus (HBV) is the major route of transmission causing persistent infection. The prevalence of HBV infection and HBV genotypes found in different geographical areas varies from country to country. Therefore, this study was conducted to identify the HBV genotypes in HBV-infected pregnant women in Northern Thailand. METHODS: Stored blood samples that were collected from 145 HBsAg-positive pregnant women who gave birth at Maharaj Nakorn Chiang Mai Hospital, Chiang Mai, Thailand from 2017 to 2020 were analyzed. The partial nucleotide sequence of the S gene of HBV was amplified by nested PCR and sequenced. All sequences were analyzed phylogenetically together with the reference strains to define the HBV genotypes. RESULTS: A total of 31 blood samples from 145 HBsAg-positive pregnant women were positive for HBV by nested PCR. The detected HBV strains were identified as presumptive subgenotypes C1 (77.4%; 24/31), B9 (9.7%; 3/31), C2 (3.2%; 1/31), B2 (3.2%; 1/31), B4 (3.2%; 1/31), and presumptive B4/C2 recombinant subgenotype (3.2%; 1/31). CONCLUSIONS: The findings revealed that presumptive subgenotype C1 was the most common subgenotype circulating in pregnant women in Northern Thailand and accounted for 77.4% of cases, followed by presumptive subgenotypes B9, C2, B2, and B4. Furthermore, this study reported, for the first time in Thailand, the HBV genotypes and presumptive subgenotypes, particularly subgenotype B9 circulating in pregnant women.