Publications by authors named "Yuko Shimizu-Onda"

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.

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Article Synopsis
  • - Noroviruses (NoVs) cause significant outbreaks of acute gastroenteritis globally, and recent research indicates the emergence of new recombinant strains in various countries, including Japan.
  • - A study analyzed 1,175 stool samples from Japanese infants and children over three years, finding 355 cases positive for NoV, with a predominance of GII genotypes, especially GII.4.
  • - The research identified multiple genotypes and recombinant strains, highlighting a decrease in NoV infections among children during and after the COVID-19 pandemic, emphasizing the need for ongoing surveillance.
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Background: Human astrovirus (HAstV) infection is one of the leading causes of acute gastroenteritis in young children. The present study reports the outbreak of HAstV in children with acute gastroenteritis in Kyoto, Japan, during the COVID-19 pandemic, 2021.

Methods: A total of 61 stool samples were collected from children with acute gastroenteritis who visited a pediatric outpatient clinic in Maizuru city, Kyoto, Japan from July to October, 2021.

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Article Synopsis
  • Human astroviruses (HAstVs) are significant causes of acute gastroenteritis (AGE) in children, with MLB1 and HAstV1 being the most common genotypes identified in Japan from 2014 to 2021.
  • Out of 2,841 stool samples collected, 4.6% tested positive for HAstVs, with MLB1 (45.4%) and HAstV1 (39.2%) dominating the infections, alongside lesser-known genotypes like MLB2 and VA2.
  • This research sheds light on the epidemiology and genetic diversity of HAstVs in Japan, marking the first detection of the rare MLB3 genotype and highlighting the potential role of HAstVs beyond gastro
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Article Synopsis
  • Norovirus (NoV) is a leading cause of gastroenteritis, particularly in children under 5, but cases dropped significantly in Japan during the COVID-19 pandemic due to school closures.
  • In September 2021, an outbreak occurred in kindergartens and nurseries in Maizuru, Kyoto, where 26 stool samples tested positive for NoV GII, with most cases showing mild symptoms like vomiting.
  • The genomic analysis of the samples revealed mutations in the NoV GII.4 Sydney[P31] strain, highlighting the need for ongoing monitoring of NoV variants in Japan.
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Since human norovirus is non-cultivable, murine norovirus and feline calicivirus have been used as surrogates. In this study, the virucidal effects of ethanol-based sanitizers with different concentrations of additives (malic acid/sodium malate, glycerin-fatty acid ester) against murine norovirus and feline calicivirus F4 were examined. The ethanol-based sanitizers at pH 7 showed sufficient virucidal effects, but glycerin-fatty acid ester included in ethanol-based sanitizers at pH 4 or 6 reduced the virucidal effects against murine norovirus.

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A total of 29 Campylobacter jejuni and C. coli strains were isolated from Thai and Japanese children with diarrhea using the Loop-mediated Isothermal Amplification method. The samples were evaluated for mutations in gyrA and 23S rRNA in order to assess resistance against fluoroquinolones and macrolides, respectively.

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We detected Campylobacter spp. in 5% (20/380) of diarrheal stool samples collected at an outpatient clinic in Kyoto using a commercial loop-mediated isothermal amplification (LAMP) kit with a fluorescent detection reagent after DNA extraction. The sensitivity and specificity were 100% in comparison with those of semi-nested PCR for the differentiation of Campylobacter jejuni and Campylobacter coli.

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This study examined the virucidal effects of five types of alcohol-based sanitizers including malic acid and sodium malate, or monoethanolamin, in 58 vol % ethanol (pH 4.0, pH 7.1, pH 11.

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