Molecular Epidemiology of Respiratory Syncytial Virus during 2019-2022 and Surviving Genotypes after the COVID-19 Pandemic in Japan.

To evaluate the changes in respiratory syncytial virus (RSV) collected between 2019 and 2022, we analyzed RSV-A and RSV-B strains from various prefectures in Japan before and after the COVID-19 pandemic. RT-PCR-positive samples collected from children with rapid test positivity at outpatient clinics in 11 prefectures in Japan were sequenced for the ectodomain of the G gene to determine the genotype. Time-aware phylogeographic analyses were performed using the second hypervariable region (HVR) of the G gene from 2012 to 2022.

Molecular Epidemiology of Norovirus (NoV) Infection in Mie Prefecture: The Kinetics of Norovirus Antigenemia in Pediatric Patients.

Few studies have shown the presence of norovirus (NoV) RNA in blood circulation but there is no data on norovirus antigenemia. We examined both antigenemia and RNAemia from the sera of children with NoV infections and studied whether norovirus antigenemia is correlated with the levels of norovirus-specific antibodies and clinical severity of gastroenteritis. Both stool and serum samples were collected from 63 children admitted to Mie National Hospital with acute NoV gastroenteritis.

Molecular characterization of rotaviruses obtained from patients with rotavirus-associated encephalitis/encephalopathy.

Group A rotavirus (RVA) rarely causes severe complications such as encephalitis/encephalopathy. However, the pathophysiology of this specific complication remains unclear. Next-generation sequence analysis was used to compare the entire genome sequences of RVAs detected in patients with encephalitis/encephalopathy and gastroenteritis.

Persistent systemic rotavirus vaccine infection in a child with X-linked severe combined immunodeficiency.

Objective: The main aims of the present study were to elucidate the systemic group A rotavirus (RVA) infection and to clarify the genetic changes of persistent virus in the X-linked severe combined immunodeficiency (SCID) patient.

Methods: RotaTeq vaccine (RV5) genotype-specific real-time reverse transcription polymerase chain reaction was used to monitor viral RNA load in serially collected serum and stool samples. Next-generation sequence analysis was used to determine the genotype of the virus by sequencing 11 gene segments.

Development of a new enzyme immunoassay for improved detection of rotavirus in fecal specimens of vaccinated infants.

Background: Group A rotavirus is the most common cause of acute diarrhea in young children worldwide. A simple and rapid enzyme immunoassay (EIA) has been commonly used to detect rotavirus infection and evaluate rotavirus vaccines. Currently licensed commercial EIA kits have low sensitivity.

Rotavirus Vaccination Can Be Performed Without Viral Dissemination in the Neonatal Intensive Care Unit.

Background: This study was conducted to assess the transmissibility of rotavirus vaccine strains after rotavirus vaccination in a neonatal intensive care unit (NICU).

Methods: Pentavalent (RV5) or monovalent (RV1) rotavirus vaccine was administered to infants admitted to the NICU. Nineteen vaccinated infants and 49 unvaccinated infants whose beds were located in close proximity to the vaccinated infants were enrolled in this study.

Evaluating the effectiveness of the universal immunization program against varicella in Japanese children.

Objective: Matched case control study was conducted to elucidate the effectiveness of the Oka/Biken vaccine immediately after implementation of the universal immunization program in Japan.

Methods: Cases were laboratory confirmed varicella patient under 15years of age diagnosed at 14 designated pediatric clinics between September 2015 and September 2016. Controls were selected from patients who visited the same practice for different reasons as the varicella case within 2weeks.

Development of real-time RT-PCR assays for detection of three classes of HHV-6A gene transcripts.

Human herpesvirus 6 (HHV-6), a member of the betaherpesvirus family, has two distinct species: HHV-6A and HHV-6B. HHV-6B real-time reverse transcription polymerase chain reaction (RT-PCR) has been used to distinguish between active and latent viral infection. In this study, we developed a real-time RT-PCR assay to detect HHV-6A-specific transcripts and evaluated its reliability for analysis of clinical samples.

Investigation of a Rotavirus Gastroenteritis Outbreak among Immunosuppressed Patients in a Hospital Setting.

Objective: Rotavirus (RV) is the most common cause of severe dehydrating diarrhoea in healthy infants and young children. The aims of this study were to investigate a RV outbreak in the pediatric hematology and oncology ward and to examine possible associations between immune status and RV infection.

Patients And Methods: Twenty-eight children (19 boys and 9 girls) who were hospitalized for treatment of hematological malignancy and solid organ tumor during the RV outbreak were enrolled in this study.

Rotavirus vaccine strain transmission by vaccinated infants in the foster home.

Previous studies have demonstrated the transmission of rotavirus vaccine strains from vaccinated children to nonvaccinated siblings. We sought to fully elucidate the safety of rotavirus (RV) vaccination in closed contact circumstance, such as the foster home for future assessment of the vaccine safety in an neonatal intensive care unit. Stool samples were collected from 4 RV vaccinated (160 samples) and 23 unvaccinated (766 samples) infants.

Breastfeeding linked to the reduction of both rotavirus shedding and IgA levels after Rotarix® immunization in Mexican infants.

We examined potential risk factors on vaccine virus shedding and antibody seroresponse to human rotavirus vaccine (Rotarix) in Mexican infants. Two doses of Rotarix were administered to infants during the first two visits for their routine childhood immunization (∼8 and 15weeks of age) in Mexico City. Infant's characteristics and socioeconomic indicators were obtained, including history of long-term feeding practices (exclusively/predominantly breastfed and exclusively/predominantly non-breastfed).

Three infants with rotavirus gastroenteritis complicated by severe gastrointestinal bleeding.

Rotavirus gastroenteritis causes substantial morbidity and mortality worldwide in children. We report three infants with rotavirus gastroenteritis complicated by various severity of gastrointestinal bleeding. Two patients (cases 1 and 2) recovered completely without any specific treatments.

Cycling probe technology to quantify and discriminate between wild-type varicella-zoster virus and Oka vaccine strains.

Rapid differentiation between wild-type varicella zoster virus (VZV) and Oka-vaccine (vOka) strains is important for monitoring side reactions of varicella vaccination. To develop a high-throughput molecular diagnostic method for the differentiation of wild-type VZV and vOka strains based on cycling probe technology. The primers were designed to amplify common sequences spanning a single nucleotide polymorphism (SNP) in gene 62 of VZV.

Serum biomarker kinetics with three different courses of HHV-6B encephalitis.

Human herpesvirus-6B (HHV-6B) encephalitis can clinically manifest as hemorrhagic shock and encephalopathy syndrome (HSES), acute encephalopathy with biphasic seizures and late reduced diffusion (AESD), and acute necrotizing encephalopathy (ANE). To compare the underlying pathophysiology, we measured several biomarkers of interest in patients with these three different courses. Based on their clinical course and neuroimaging analysis, Cases 1, 2 and 3 were diagnosed as HSES, AESD, and ANE, respectively.

Development of quantitative RT-PCR assays for detection of three classes of HHV-6B gene transcripts.

The monitoring of active human herpesvirus 6 (HHV-6) B infection is important for distinguishing between the reactivation and latent state of the virus. The aim of this present study is to develop a quantitative reverse transcription polymerase chain reaction (RT-PCR) assay for diagnosis of active viral infection. Primers and probes for in house quantitative RT-PCR methods were designed to detect the three kinetic classes of HHV-6B mRNAs (U90, U12, U100).

Cytokine and chemokine responses in pediatric patients with severe pneumonia associated with pandemic A/H1N1/2009 influenza virus.

Severe pneumonia and leukocytosis are characteristic, frequently observed, clinical findings in pediatric patients with pandemic A/H1N1/2009 influenza virus infection. The aim of this study was to elucidate the role of cytokines and chemokines in complicating pneumonia and leukocytosis in patients with pandemic A/H1N1/2009 influenza virus infection. Forty-seven patients with pandemic A/H1N1/2009 influenza virus infection were enrolled in this study.

Correlation between serum matrix metalloproteinase and antigenemia levels in patients infected with rotavirus.

Rotavirus (RV) antigenemia has been reported in patients with gastroenteritis; however, the exact mechanism remains unclear. In order to elucidate the mechanism of RV antigenemia, an association between RV antigenemia and matrix metalloproteinase (MMP) were analyzed. The object of this study was to elucidate the role of MMPs and tissue inhibitors of metalloproteinases (TIMPs) in the pathogenesis of RV antigenemia.

Development of a human herpesvirus 6 species-specific immunoblotting assay.

In order to assess the full spectrum of human herpesvirus 6A (HHV-6A)- and HHV-6B-associated diseases, we sought to develop an HHV-6 species-specific serological assay based on immunoblot analysis. The immunodominant proteins encoded by open reading frame U11, p100 for HHV-6A (strain U1102) and 101K for HHV-6B (strain Z29), were selected to generate virus species-specific antigens. Recombinant p100 and 101K were produced in a prokaryotic expression system.

Host factors associated with the kinetics of Epstein-Barr virus DNA load in patients with primary Epstein-Barr virus infection.

The aims of this study were to elucidate the kinetics of Epstein-Barr virus (EBV) DNA load in serially collected peripheral blood mononuclear cells of patients with primary EBV infection, and to determine the correlated host factors. Blood samples were collected from 24 patients with primary EBV infection. EBV DNA copy numbers were measured using real-time polymerase chain reaction.

Different characteristics of human herpesvirus 6 encephalitis between primary infection and viral reactivation.

Background: Pathogenesis of human herpesvirus 6 (HHV-6) encephalitis, in particular difference between HHV-6 encephalitis at the time of primary infection and reactivation remains unclear.

Objectives: To elucidate the mechanism of HHV-6 encephalitis at the time of primary infection and reactivation.

Study Design: Twenty-two HHV-6 encephalitis patients at the time of primary infection, 6 febrile convulsion (FC) patients caused by HHV-6 infection, and 14 FC patients without HHV-6 infection (non HHV-6 FC) were enrolled.

A case of erythema multiforme associated with primary Epstein-Barr virus infection.

We present a case of primary Epstein-Barr virus (EBV) infection with erythema multiforme. A 1-year-old Japanese boy presented with skin eruptions, including typical target lesions and a low-grade fever. Just before the skin biopsy, 95 copies/μg DNA of EBV genome was detected in peripheral blood mononuclear cells, which subsequently increased to 6,834 copies/μg DNA.

Evaluation of reverse transcription loop-mediated isothermal amplification assays for rapid diagnosis of pandemic influenza A/H1N1 2009 virus.

Two genetic diagnosis systems using reverse transcription-loop-mediated isothermal amplification (RT-LAMP) technology were evaluated: one for detecting the HA gene of the pandemic influenza A/H1N1 2009 virus (H1pdm RT-LAMP) and the other for detecting the matrix gene of the influenza A virus (TypeA RT-LAMP). The competence of these two RT-LAMP assay kits for the diagnosis of the pandemic influenza A/H1N1 2009 virus was compared using real-time RT-PCR assays developed recently on viruses isolated and clinical specimens collected from patients with suspected infection. TypeA RT-LAMP and H1pdm RT-LAMP showed almost the same sensitivity as real-time RT-PCR for viruses isolated.

Direct detection of human herpesvirus 6 DNA in serum by variant specific loop-mediated isothermal amplification in hematopoietic stem cell transplant recipients.

A variant specific direct loop-mediated isothermal amplification (LAMP) method was developed to detect human herpesvirus-6 (HHV-6) variants in serum samples. Specific primers were designed against HHV-6 U86 gene. Initial validation analysis confirmed high specificity and sensitivity of the method.

Exanthem subitum-associated encephalitis: nationwide survey in Japan.

We sought to clarify clinical features of exanthem subitum associated-encephalitis/encephalopathy, generally caused by primary human herpesvirus-6 infection in Japan. A two-part questionnaire was sent to hospitals between January 2003-December 2004. Of 3357 questionnaires, 2357 (70.