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.

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.

Epidemiology and associated factors for hospitalization related respiratory syncytial virus infection among children less than 5 years of age in Northern Thailand.

BACKGROUND: Respiratory syncytial virus (RSV) is often the main problem in young children that require hospitalization. The objective of this study was to identify factors associated with RSV-related hospitalizations in young children less than five years old. METHODOLOGY: A retrospective study was conducted for acute respiratory tract infection (ARTI) at a tertiary care hospital from January 2017 to December 2021 by using binary logistic regression analysis to detect the associated factors with RSV-related hospitalizations in children. RESULTS: RSV-related hospitalization was detected in 293 of 410 (71.46 %) cases of RSV infection, most of which appeared in the rainy months of August to November. The most common symptoms and signs were 81.5 % rhinorrhea, 70.7 % cough, 68.5 % sore throat, 68.3 % sputum production, and 66.8 % fever. Factors associated with RSV-related hospitalization were age less than or equal to 2 years (aOR = 4.62, 95 % CI = 1.86-11.44), preterm birth (aOR = 2.61, 95 % CI = 1.05-6.10), patients with underlying disease (aOR = 3.06, 95 % CI = 1.21-10.34), and the presenting symptoms with sputum production (aOR = 16.49, 95 % CI = 3.80-71.55). Laboratory blood tests, low levels of hematocrit (aOR = 9.61, 95 % CI = 1.09-84.49) was the associated factor for hospitalization with RSV infection (p < 0.05). CONCLUSIONS: Factors associated with RSV-related hospitalizations in children were age less than or equal to two years, preterm birth, underlying disease, symptoms of sputum production. The low level of hematocrit was also associated with RSV-related hospitalizations in these children.

Possible Association between Genetic Diversity of Hepatitis B Virus and Its Effect on the Detection Rate of Hepatitis B Virus DNA in the Placenta and Fetus.

Background: The prevalence of HBV infection and HBV genotypes varies from country to country, and the role of HBV genotypes in the presence of HBV in the placenta and fetus has never been explored. This study was conducted to (1) identify HBV genotypes, and their frequencies, that infected Northern Thai pregnant women; (2) evaluate the association between HBV genotypes and the detection rate of HBV DNA in the placenta and fetus; (3) evaluate the association between specific mutations of the HBV genome and HBV DNA detection in placental tissue; and (4) identify the mutation of the HBV genome that might occur between maternal blood, placenta, and cord blood. Methods: Stored samples of the maternal blood, placental tissue, and cord blood that were collected from 145 HBsAg-positive pregnant Thai women were analyzed to identify HBV DNA. Results: Approximately 25% of infected mothers had fetal HBV DNA detection, including cases with concomitant HBV DNA detection in the placenta (77.3%). A total of 11.7% of cases with placental detection had no HBV DNA detection in the maternal blood, indicating that the placenta could be a site of HBV accumulation. Of the 31 HBV-positive blood samples detected by nested PCR, the detected strains were subgenotype C1 (77.4%), subgenotype B9 (9.7%), and subgenotype C2, B2, B4, and recombinant B4/C2 (3.2% for each). Genotype B had a trend in increased risk of placental HBV DNA detection compared to genotype C, with a relative risk of 1.40 (95% CI: 1.07-1.84). No specific point mutation had a significant effect on HBV DNA detection in placental tissue. Mutation of C454T tended to enhance HBV DNA detection in placental tissue, whereas T400A tended to have a lower detection rate. No mutation was detected in different sample types collected from the same cases. Conclusions: HBV DNA detection in the fetus was identified in approximately 25% of HBV-positive mothers, associated with the presence of HBV in the placenta in most cases. The placenta could possibly be a site of HBV accumulation. Subgenotype C1 was the most common subgenotype, followed by subgenotype B9. HBV genotype B possibly had a higher trend in intrauterine detection than HBV genotype C. Mutation is unlikely to occur during intrauterine exposure.

Predominance of ON1 and BA9 genotypes of human respiratory syncytial virus in children with acute respiratory infection in Chiang Mai, Thailand, 2020-2021.

BACKGROUND: Human respiratory syncytial virus (hRSV) is an important cause of acute respiratory infection, especially in children. Few studies have investigated molecular epidemiology of hRSV infection in Thailand. The aims of this study were to investigate the prevalence and genotype diversity of hRSV in children with acute respiratory infection (ARI) in Thailand. METHODS: A total of 383 nasopharyngeal swabs collected from children with ARI from October 2020 to September 2021 were screened for hRSV and nucleotide sequences of the hypervariable region 2 (HVR2) of G gene of the detected hRSV were analysed. RESULTS: Of 383 nasopharyngeal swabs, 104 (27.2 %) were positive for hRSV, of which 51 (49.0 %), 43 (41.3 %), and 10 (9.6 %) were hRSV-A, hRSV-B, and untypeable strains, respectively. All hRSV-A and hRSV-B were ON1 genotype and BA9 genotype, respectively. Most of the hRSV strains were detected in the cool months, November 2020 to February 2021. Phylogenetic analysis of the HVR2 sequence of G gene revealed three clusters of hRSV-A (ON1 genotype) and two clusters of hRSV-B (BA9 genotype). The hRSV-A strains in cluster 1 and 3 were closely related to the hRSV-A reference strains reported previously from other regions of Thailand whereas those in cluster 2 were closely related to the hRSV-A reference strains reported previously from Europe and Africa. For the hRSV-B strains, both clusters 1 and 2 were closely related to the hRSV-B reference strains reported previously from Europe, Australia, and Taiwan. The predicted N- and O-linked glycosylation sites were found along the length of HVR2 of G protein, mostly in the hRSV-B strains. CONCLUSIONS: The ON1 and BA9 were the only two hRSV genotypes that were co-predominant and solely detected in this study. The findings indicated that the ON1 and BA9 are the only two hRSV genotypes currently circulating in children with ARI in northern Thailand.

Characteristics of Respiratory Syncytial Virus Infection in Hospitalized Children Before and During the COVID-19 Pandemic in Thailand.

OBJECTIVES: This study compared the epidemiological and clinical manifestations of patients hospitalized with respiratory syncytial virus (RSV) infection before and during the coronavirus disease 2019 (COVID-19) pandemic at a tertiary care hospital in Chiang Mai Province, Thailand. METHODS: This retrospective observational study utilized data from all cases of laboratory-confirmed RSV infection at Maharaj Nakorn Chiang Mai Hospital from January 2016 to December 2021. Differences in the clinical presentation of RSV infection before (2016 to 2019) and during (2020 to 2021) the COVID-19 pandemic were analyzed and compared. RESULTS: In total, 358 patients hospitalized with RSV infections were reported from January 2016 to December 2021. During the COVID-19 pandemic, only 74 cases of hospitalized RSV infection were reported. Compared to pre-pandemic levels, the clinical presentations of RSV infection showed statistically significant decreases in fever on admission (p=0.004), productive cough (p=0.004), sputum (p=0.003), nausea (p=0.03), cyanosis (p=0.004), pallor (p<0.001), diarrhea (p<0.001), and chest pain (p<0.001). Furthermore, vigilant measures to prevent the spread of COVID-19, including lockdowns, also interrupted the RSV season in Thailand from 2020 to 2021. CONCLUSIONS: The incidence of RSV infection was affected by the COVID-19 pandemic in Chiang Mai Province, Thailand, which also changed the clinical presentation and seasonal pattern of RSV infection in children.

Awareness and Attitudes Toward HIV Self-Testing in Northern Thailand.

Human Immunodeficiency Virus self-testing (HIVST) was recently introduced in Thailand, but little is known about receptivity among its residents. Because Human Immunodeficiency Virus (HIV) testing is a critical component of HIV prevention, it is important to understand how HIVST is perceived among potential users. The purpose of this study was to examine awareness and attitudes toward HIVST among adults in Northern Thailand. A convenience sample of 403 adult residents of the Sanpatong district, Chiang Mai Province, was interviewed using a structured questionnaire in 2019. Awareness of HIVST was low (14%), as was the overall HIVST negative attitude score (6.44; possible range of 0-14). The odds of being aware of HIVST were more than twice as high for those with more education compared to those with less (AOR = 2.29, 95% CI: 1.22-4.30), and roughly half as high for those who expressed HIV stigma compared to those who did not (AOR = 0.49, 95% CI: 0.26-0.91). Holding negative attitudes towards HIVST also was associated with lower education and expressing HIV stigma, but these relationships disappeared in multivariate analysis. Findings may be used by local health organizations to tailor HIVST education efforts.

Macronutrient, immunoglobulin a and total antioxidant capacity profiles of human milk from 1 to 24 months: a cross-sectional study in Thailand.

BACKGROUND: An extended duration of breastfeeding of up to two years is encouraged by many health authorities, but information regarding the composition of milk after one year postpartum is limited. The goal of this study was to determine the association between the duration of lactation and macronutrient contents, immunoglobulin A (IgA) levels and total antioxidant capacity (TAC) in human milk (HM), from 1 to 24 months postpartum. METHODS: Cross-sectional milk samples were collected between January and April 2019 from mothers with healthy full-term children who had been lactating for 1 to 24 months. The HM was biochemically analyzed for protein and carbohydrate contents by colorimetric assays. The fat content was determined by capillary centrifugation, and the energy content was calculated from the results of centrifugation assays. IgA levels and TAC were determined by ELISA and a Trolox equivalent antioxidant capacity (TEAC) assay, respectively. Pearson's correlation coefficient and Spearman's rank correlation coefficient were used to determine associations between months of lactation and milk composition, and multiple regression analysis was used to assess associations between months of lactation and milk composition adjusted for relevant covariates. Differences were considered significant at p < 0.05. RESULTS: One hundred eighty-four milk samples were analyzed. The month of lactation was positively associated with the fat concentration (B = 0.31, SE = 0.09, p = 0.001), energy content (B = 3.11, SE = 0.92, p = 0.001), and IgA (B = 4.17, SE = 1.08, p < 0.001) but negatively associated with the carbohydrate concentration (B = - 0.22, SE = 0.01, p = 0.04). No association was observed between the month of lactation and the protein concentration or TAC after adjustment for maternal age, maternal BMI, birth order, and breastfeeding frequency. CONCLUSION: The duration of lactation was found to be positively associated with the fat, energy, and IgA content in HM for up to two years postpartum, and negatively associated with carbohydrate concentration. More prospective cohort studies are needed to obtain evidence-based knowledge regarding the changes in HM composition throughout the course of lactation.

Genetic diversity of norovirus genogroup I, II, IV and sapovirus in environmental water in Thailand.

BACKGROUND: Enteric caliciviruses, including noroviruses (NoVs) and sapoviruses (SaVs) are the most significant pathogens associated with waterborne and foodborne outbreaks of nonbacterial acute gastroenteritis in humans worldwide. METHODS: In this study, 126 environmental water samples collected from 6 different sources in Chiang Mai, Thailand from November 2016 to July 2018 were examined for the presence of genogroups I, II, IV (GI, GII, GIV) NoVs and SaVs by using RT-nested PCR assays, genome sequencing, and phylogenetic analysis, RESULTS: Forty out of 126 (31.7%) water samples were positive for one or more caliciviruses throughout the years of study with high prevalence in winter. Among 126 tested specimens, 34 (27.0%), 30 (23.8%), 3 (2.4%), and 2 (1.6%) were positive for NoV GI, GII, GIV, and SaV, respectively. For NoV GI, 6 different genotypes were identified with the most predominant of GI.1 genotype (17 strains). In addition, 6 different genotypes of GII were detected with high prevalence of GII.17 (12 strains) and GII.2 (11 strains). It was interesting to note that our study reported the detection of NoV GIV for the first time in water samples in Thailand, and all were GIV.1 genotype. For SaV detection, only 2 water samples were positive for SaV GI. CONCLUSIONS: The data revealed heterogeneity and highly dynamic distribution of NoV GI, GII, GIV, and SaV in environmental water in Chiang Mai, Thailand, during the study period of 2016-2018.

Combined Black Rice Germ, Bran Supplement and Exercise Intervention Modulate Aging Biomarkers and Improve Physical Performance and Lower-Body Muscle Strength Parameters in Aging Population.

Aging is a time-dependent functional decline in muscle mass and strength, which is reflected in poor physical performances, hormonal imbalance, and development of chronic low-grade inflammation. This study aimed to assess the effectiveness of black rice germ, bran supplement, and exercise program either alone or in combination for 24 weeks on the aging biomarkers (C-reactive protein, Interleukin-6, Insulin-like growth factor-1, and CD4:CD8 T cell ratio) physical performance, muscle strength parameters (walking speed, sit-to-stand time, grip strength) among Thai aging population. A total of 120 healthy volunteers aged 65-74 years were assigned to the exercise group (EX), black rice germ, and bran supplement (BR) group or the combination of BR and EX group (BR + EX). Over the course of the 24-week intervention, compared with baseline data (T0), the combined BR + EX intervention significantly decreased the inflammatory biomarkers (C-reactive protein and interleukin-6 levels, both p < 0.05 vs. T0) and significantly increased the insulin-like growth factor-1 levels (p < 0.001 vs. T0). Significant improvement in physical performance and muscle strength were also observed in the combined BR + EX group (decrease in sit-to-stand time and gait speed over the 24-week intervention, both p < 0.05 vs. T0, and trend toward grip strength improvement at p = 0.088 vs. T0). Overall, our results indicated a synergistic effect towards the combined intervention with the sustainable improvement in physical performances, lower-body muscle strength, and the modulation of both inflammatory and endocrine biomarkers. This study could encourage older adults to change their lifestyles to improve healthy aging and longevity.

Placental infection of hepatitis B virus among Thai pregnant women: Clinical risk factors and its association with fetal infection.

OBJECTIVES: To identify the risk factors of placental and fetal infections among HBsAg-positive women. METHODS: A prospective cohort study involving HBsAg-positive pregnant women was conducted. Maternal risk factors, including serum HBeAg status, anti-HBcIgM, and HBV-DNA levels, were determined. Placental infection was identified by PCR and confirmed by DNA sequencing. Fetal infection was defined as a positive umbilical cord blood HBV-DNA at birth. RESULTS: A total of 96 HBsAg-positive women were enrolled in the study. The prevalence of placental infection was high (44 of 96; 45.8%) among HBsAg-positive women. The major risk factors for placental infection were high maternal viral load and the presence of HBeAg. Fetal infection was detected in one quarter of HBsAg-positive women (25 of 95; 25.3%). The risk of fetal infection was strongly associated with placental infection (78.3%), high maternal viral load, and the presence of HBeAg. There was no significant difference in perinatal outcomes between the groups with and without placental infection. Data on rates of chronic HBV infection in infants after fetal infection were not available. CONCLUSION: A significant association between maternal measures of viral replication and placental and fetal infection was demonstrated. These findings suggest that transplacental infection prior to birth may be a mechanism contributing to the higher rates of newborn prophylaxis failure in women with a high viral load.

The Association between Frailty Indicators and Blood-Based Biomarkers in Early-Old Community Dwellers of Thailand.

Thailand has officially reached the status of an "aged society" and become the developing country with the 2nd largest proportion of senior citizens in Southeast Asia. A cross-sectional study of 526 early-old community dwellers was conducted for the Fried frailty phenotype assessment, This included five indicators: Weakness, slowness, physical activity, exhaustion, and weight loss. C-reactive protein (CRP), interleukin-6 (IL-6), insulin-like growth factor-1, and CD4+:CD8+ Ratio which serve as blood-based biomarkers of frailty. The prevalence of frailty and pre-frail in this population was found to be 15% and 69.6% respectively and was higher among women than men. Frail (n = 58) and non-frail (n = 60) participants were evaluated for the associations between the frail indicators and the blood-based biomarkers. Serum levels of IL-6 and CRP from frail group were significantly elevated when compared with the non-frail counterparts (p = 0.044 and 0.033, respectively), and were significantly associated with the frailty status with an Odd RatioIL-6 [OR] of 1.554-fold (95% confidence interval [CI], 1.229-1.966) and an ORCRP of 1.011-fold (95 CI, 1.006-1.016). Decreased hand-grip strength was the only frailty indicator that was significantly associated with both inflammatory biomarkers, (ORIL-6 of 1.470-fold and ORCRP of 1.008-fold). Our study is the first to assess the frailty status among the early-old population in Thailand. These findings will encourage general practitioners to combine frailty indicators and serum biomarkers as early detection tools for at-risk older adults to achieve the goal of healthy aging.

Molecular surveillance and genetic analyses of bufavirus in environmental water in Thailand.

Bufavirus (BuV), a recent discovery virus of the family Parvoviridae, has been suggested to be a potential causative agent of diarrhea in humans. The prevalence of BuV has been demonstrated mostly in fecal specimens of diarrheic patients. Little is known about the presence of BuV in the environmental water. The aim of the present study was to conduct a surveillance for BuV in the environmental water in Thailand. A total of 125 water samples were collected during November 2016 and July 2018 from six different areas in Chiang Mai city, Thailand. Water samples were concentrated and extracted to obtain BuV genomic DNA. The BuV was screened by amplification of NS1 region using nested-PCR. The detected BuV was further characterized by amplification of VP2 region. The NS1 and VP2 genes were sequenced and analyzed phylogenetically. The BuV strain (CMW88/18) detected in this study belonged to BuV1 with the prevalence of 0.8%. The CMW88/18 strain was most closely related to human BuV1 strains reported previously worldwide suggesting contamination of BuV in the environmental water could be a potential source of infection in human.

Characterization of Erythromycin and Tetracycline Resistance Genes of Streptococcus gallolyticus Subspecies pasteurianus Strains Isolated from Patients with Septicemia and Bacteremia in Thailand.

BACKGROUND: Streptococcus gallolyticus subspecies (subsp.) pasteurianus, previously known as Streptococcus bovis biotype II/2, has been described as a causative agent of endocarditis, neonatal sepsis, meningitis, bacteremia, and colorectal carcinoma in humans. The aim of this study was to characterize the erythromycin and tetracycline resistance genes of S. gallolyticus subsp. pasteurianus strains isolated from patients with septicemia and bacteremia in Thailand. METHODS: The clinical isolates of Streptococcus gallolyticus were identified by using conventional biochemical tests, PCR, and sodA gene sequence analysis. The erythromycin and tetracycline susceptibilities were determined by disk diffusion and agar dilution methods, while the resistance genes were identified by nucleotide sequence analysis. RESULTS: From a total of 108 blood cultures, 36 (33%) were identified as S. gallolyticus subsp. pasteurianus with the nucleotide sequence identities of partial sodA gene with the reference strains ranging from 98.1 to 100%. Of these, 25 (69.4%) contained erythromycin resistance genes and erm(B) was the most predominant gene (30.6%), followed by erm(T) (19.4%) and mef(A) (5.6%). In addition, erm(B) was also detected in combination with lnu(B) (8.3%), erm(T) and mef(A) (2.8%), and mef(A) and lnu(B) (2.8%). It was interesting to note that lnu(B) was detected for the first time in S. gallolyticus subsp. pasteurianus in this study. For tetracycline resistance genes, tet(L) and tet(M) were detected at 13.9% and 11.1%, respectively. However, tet(M) in combination with tet(L) was detected most commonly at 69.4% and with tet(L) and tet(O) at 5.6%. CONCLUSIONS: A number of erythromycin and tetracycline resistance genes were detected in S. gallolyticus subsp. pasteurianus strains circulating 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.

Distribution of norovirus and sapovirus genotypes with emergence of NoV GII.P16/GII.2 recombinant strains in Chiang Mai, Thailand.

Norovirus (NoV) and sapovirus (SaV) are recognized as the causative agents of acute gastroenteritis, and NoV is one of the leading pathogens reported worldwide. This study reports on the distribution of NoV and SaV genotypes in children hospitalized with acute gastroenteritis in Chiang Mai, Thailand, from January 2015 to February 2017. From a total of 843 stool samples, 170 (20.2%) and 16 (1.9%) were identified as having NoV and SaV infections, respectively. Two samples (0.2%) were positive for both NoV and SaV. Of these, NoV GII.4 (57.2%) was the dominant genotype, followed by GII.2, GII.3, GII.17, GII.6, GII.7, GII.13, GII.14, GII.15, GII.21, GI.6, and GI.5. Among the NoV GII.4 variants, Sydney 2012 was the dominant variant during the period 2015-2016, while the other variants detected in this study were Asia 2003 and New Orleans 2009. Interestingly, an increase of NoV GII.2 was observed in 2016 and 2017. Characterization of partial RNA-dependent RNA polymerase and VP1 nucleotide sequences of GII.2 strains revealed that more than half of the GII.2 strains circulating in 2016 and 2017 were recombinant strains of GII.P16/GII.2. For SaV, the majority of strains belonged to GI.1 (55.6%) and GI.2 (33.3%), while GII.5 accounted for 11.1%. In conclusion, this study demonstrates the diversity of NoV and SaV, and the emergence of NoV GII.P16/GII.2 recombinant strains in 2016 and 2017 in Chiang Mai, Thailand.

Molecular epidemiology and characterization of porcine adenoviruses in pigs with diarrhea in Thailand.

Pigs have been assumed as a source of human viral infections. Surveillance of viruses in animals is essential to evaluate the risk to human and animal health and to determine economic impact. A number of studies focused mainly on well- known enteritis viruses such as porcine epidemic diarrhea virus (PEDV), transmissible gastroenteritis virus (TGEV), and porcine group A rotavirus (PRVA), however, little data is available for porcine adenovirus (PAdV). In this study, the presence of PAdV was investigated in fecal samples collected from piglets with and without diarrhea from 31 commercial pig farms in northern Thailand. A total of 781 fecal specimens (516 from diarrheic piglets and 265 from non-diarrheic piglets) were screened for adenovirus using nested-PCR. Initial screening both in diarrheic and non-diarrheic piglets showed the overall prevalence of PAdV infection in piglets at 16.9% (132/781). Co-infection with PRVA was found in 24 out of 132 (18.2%) PAdV positive cases whereas PAdV mono-infection was observed at 81.8% (108/132). The prevalence of PAdV infection in diarrheic piglets (24.2%, 102/516) was significantly higher than those detected in non-diarrheic piglets (2.6%, 7/265). Most of PAdV detected in this study (97%, 128/132) were genotype 3 while the other 4 PAdV positive samples were non identifiable genotype. Phylogenetic analysis revealed that the viruses detected in diarrheic and non-diarrheic piglets displayed a closely related (95.4 to 100%) nucleotide sequence identity. To our knowledge, this is the first report on the epidemiology and molecular characterization of PAdV in piglets in Thailand.

Complete genome sequence analysis of rare G4P[6] rotavirus strains from human and pig reveals the evidence for interspecies transmission.

Two rare human rotavirus strains, RVA/Human-wt/THA/CMH-N016-10/2010/G4P[6] and RVA/Human-wt/THA/CMH-N014-11/2011/G4P[6], were detected during the surveillance of group A rotavirus (RVA) in Chiang Mai, Thailand. Complete genome sequences of both strains were analyzed in comparison with that of the representative porcine G4P[6] RVA strain (RVA/Pig-wt/THA/CMP-011-09/2009/G4P[6]) detected in the same geographical area. Human RVA strain CMH-N016-10 containing the genotype constellation of G4-P[6]-I1-R1-C1-M1-A8-N1-T1-E1-H1 was identical to that of porcine RVA strain CMP-011-09. Another human RVA strain (CMH-N014-11) was also contained the genotype constellation of ten segments identical to those of CMH-N016-10 and of porcine RVA strain CMP-011-09 except for genotype I of VP6 gene which contained I5 instead of I1. The genotype constellation of CMH-N014-11, G4-P[6]-I5-R1-C1-M1-A8-N1-T1-E1-H1 was a novel genotype constellation that has not been reported previously in both human and pig. Phylogenetic analysis of all 11 genome segments revealed that both strains of human RVA were more closely related to porcine and porcine-like human than to human RVA reference strains, particularly those reported from Thailand and other Asian countries with very high nucleotide sequence identities ranging from 91.1-100% except for NSP4 gene from 86.1-92.2%. Based on complete genome constellation and overall phylogenetic analyses suggested that these two human G4P[6] strains may have probably originated from porcine RVA strains of independent ancestor. This study provided an evidence for direct interspecies transmission of porcine RVA from pig to human.

Molecular detection and genetic characterization of Salivirus in environmental water in Thailand.

Salivirus (SalV), also known as klassevirus, is a newly discovered member of the Picornaviridae family, which has been proposed to be a potential causative agent of acute gastroenteritis. This study aimed to provide further insight into the currently limited epidemiological data of SalV in environmental water in Thailand, which could be a potential source of human infection. A total of 95 water samples were collected from six locations in Chiang Mai province, northern Thailand, between November 2016 and February 2018. The molecular screening for SalV was performed by the nested polymerase chain reaction. The SalV genotypes were then determined through nucleotide sequencing and phylogenetic analysis. SalV was detected in 31 out of the 95 (32.6%) water samples and all belonged to the A1 genotype, based on phylogenetic analysis of the 5'UTR and 3D regions. The SalV-A1 strains detected in the environmental water were closely related to the SalV-A1 detected in a patient with diarrhoea in the same geographical area, based on the nucleotide sequence identities of the 5'UTR and 3D regions ranging from 91 to 99% and 96-99%, respectively. This study reports the prevalence of SalV-A1 contamination in environmental water in Chiang Mai, Thailand.

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.