フィリピンにおけるRespiratory Syncytialウイルスの遺伝子解析、2012～2015年

Tohoku University押谷　仁課

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

Complete Genome Sequences of 13 Human Respiratory Syncytial Virus Subgroup A Strains of Genotypes NA1 and ON1 Isolated in the Philippines

Complete genome sequences of 13 human respiratory syncytial virus strains were determined from samples obtained from children hospitalized in the Philippines between 2012 and 2013 because of acute respiratory infection. We identified amino acid polymorphisms between the NA1 and ON1 genotypes in the P, G, F, and L proteins

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

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

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