Human rhinovirus (HRV) commonly causes mild respiratory illness but may occasionally result in severe disease requiring hospitalization. Herein, we report a respiratory outbreak at a residential hospital for individuals with severe motor and intellectual disabilities (SMID) where HRV was detected. The facility housed 47 residents, 31 of whom developed symptoms. Further, 20 symptomatic patients were tested, and HRV-C was detected in 15 of them using RT-PCR. The nucleotide identity of the detected strains was 100%, and based on phylogenetic analysis, the strain was identified as the HRV-C56 type. No other pathogens were detected. Although the specific mode of transmission remains unclear, the patients had been residing at the facility for an extended period of time with limited mobility. Therefore, healthcare workers or visitors may have been the source of infection. In this outbreak, HRV-C disseminated rapidly among the residents, resulting in the spread of infections to healthcare workers and affecting healthcare. It is imperative for medical institutions, particularly long-term care facilities, to establish systems for the early detection and management of respiratory infections.

Mumps vaccination, which is routinely administered in many countries, is not covered by Japan's national immunization program. Therefore, mumps epidemic occurs every 3 or 4 years in Japan due to a low vaccine coverage rate. To prepare for the next resurgence, we examined the immunity against mumps using neutralizing antibodies (NT) against vaccine strain (genotype B) and wildtype virus (genotype G), and mumps-specific enzyme immunoassay for immunoglobulin G (IgG). We enrolled 83 children admitted to the Kawasaki Medical Hospital for diseases other than mumps between April and December 2022. The positive rates of NT for both of wild type and vaccine type were lower (25 .3%) than that of IgG (38.5%). No significant difference among them. Though individual infection histories were not confirmed, the absence of any mumps epidemic during the coronavirus disease pandemic, Therefore, almost all enrolled children were unlikely to have been infected with mumps, that is, they might have acquired immunity only by voluntary vaccinations. Therefore, we evaluate the immunity for mumps in the real world at three novel points as follows, (1) to evaluate under non-national immunization program (2) to evaluate Hoshino vaccine strains (3) to evaluate both IgG and the other immunity.

We report a rare case of human brucellosis caused by Brucella suisbiovar 5 in a 75-year-old man from Nagano Prefecture, Japan. He had no history of immune disorders and presented with fatigue, left ankle pain, and swelling. Initial antimicrobial therapy for suspected cellulitis and tenosynovitis failed, leading to admission to our hospital. Imaging and synovial fluid analysis suggested septic arthritis with a periarticular abscess. Gram-negative rods were recovered from synovial fluid obtained via arthrocentesis of the left ankle joint. Although the isolate could not be identified using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry using a MALDI Biotyper system, it was successfully identified as B. suisbiovar 5 using species-specific PCR and nine-locus multilocus sequence typing (MLST). The patient was successfully treated with surgical debridement and prolonged antimicrobial therapy. This is the third documented human case of B. suisbiovar 5 infection in Japan, all originating from Nagano Prefecture, suggesting a localized cluster. This case highlights the diagnostic challenges of brucellosis, the limitations of routine identification methods, and the biosafety concerns for clinical laboratories. Enhanced awareness and surveillance are warranted in regions with emerging cases.

Information regarding the disease burden of respiratory syncytial virus (RSV) infection among the elderly in Japan is limited. A comprehensive review of the medical records from January 1, 2002, to December 31, 2023, was conducted for adult cases of community-onset pneumonia encountered in routine clinical practice at a community hospital in Shiogama, Japan. The pneumonia case definition employed in this study, for pathogens including major respiratory viruses, required laboratory diagnosis supported by solid virological data, such as virus isolation or rising antibody titers, rather than merely gene detection. The results indicated that, before the emergence of the Coronavirus disease-2019 pandemic in 2020, RSV and influenza virus infections accounted for a substantial proportion (30% each) of the detected respiratory viruses, and RSV persisted as the second most prevalent virus, surpassed only by Severe Acute Respiratory Syndrome Coronavirus-2, even after the pandemic emerged. The mortality rate associated with RSV as a prognostic factor reached 5-10%, depending on the period. The temporal pattern of case emergence from June 2011 to March 2025 suggested that community-acquired RSV infections in children likely precede the occurrence of RSV pneumonia in adults.

The proportion of people who have anti-nucleocapsid (N) protein antibodies against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been reported as a surrogate for the proportion of previously infected individuals. This seroepidemiologic survey, conducted from 6 November 2023 to 19 January 2024, aimed to measure the levels of anti-N protein antibodies produced in the body by SARS-CoV-2 among residents over 18 years of age in Bizen City, Okayama, Japan. We evaluated the prevalence of SARS-CoV-2 antibodies in the target population at the time of the investigation and assessed changes over time among participants who had previously been infected. Of the 444 participants, a total of 235 (52.9%) were infected within one year. The seroprevalence of participants testing positive remained above 80% until four months post-infection, after which the number of people who remained positive declined rapidly. Six months after infection, around 10% of participants tested positive for anti-N protein antibodies, and this seroprevalence remained the same for up to one year post-infection. We demonstrated that the anti-N protein antibodies test is useful for identifying recently infected individuals for several months post-infection. We showed that it becomes increasingly difficult to detect past infections as time elapses since infection.

Disasters such as earthquakes create conditions that amplify the risk of ectoparasitic infestations due to overcrowding, disrupted sanitation, and limited hygiene resources. This study explores ectoparasite-related online search interests in Türkiye before and after the earthquakes of February 2023, offering insights into potential secondary health concerns during disaster recovery. Weekly Google Trends data on scabies, lice, bed bugs, ticks, and insect bites were extracted for Türkiye and its provinces. Relative search volumes (RSV) were analysed to compare two years pre- and post-earthquake periods. Statistical analyses included time series comparisons. Following the earthquake, RSV for scabies and bed bugs increased sharply, while lice RSV significantly declined; tick and insect bite queries maintained consistent seasonal cycles. Integrating digital epidemiology insights with field-based surveillance could enhance the early detection and response to outbreaks following disasters. Long-term monitoring should be included in surveillance systems.

Escherichia coli O157 and O26 are well-known Shiga toxin-producing E. coli (STEC) serotypes, but other serotypes such as O91, O103, O111, O121, O145, and O165 have also emerged as important public health concerns. PCR-based methods, such as multilocus variable-number tandem-repeat analysis (MLVA), are commonly used for rapid genotyping of STEC strains. However, MLVA requires analysis of numerous loci, some of which are serotype-specific, limiting its applicability across multiple STEC serotypes. In this study, we developed a PCR-based open reading frame typing (POT) method for genotyping diverse STEC serotypes. By detecting 22 ORFs using two multiplex PCR assays, STEC genotypes were determined based on the presence or absence of specific ORFs. Most STEC serotypes, except for O121, were classified with high discriminatory power (Simpson's index: 0.95-0.98). STEC-POT represents a rapid, cost-effective, and broadly applicable molecular typing tool. It facilitates timely outbreak detection and enhances public health surveillance by enabling rapid molecular epidemiological investigations.

This large-scale post-marketing surveillance study (163 sites; February 2022-May 2023) evaluated the real-world safety and effectiveness of a newly initiated nirmatrelvir plus ritonavir combination for patients with COVID-19 in Japan. The current study reports the safety evaluation. The observation period was 28 days after the last day of administration. The safety analysis set comprised 2829 patients (mean [standard deviation] age, 63.1 [18.0] years; mild COVID-19, 80.8%; ≥1 risk factor for progression to severe COVID-19, 97.3%). The most common reason for discontinuing follow-up was symptom improvement (17.1%). Adverse drug reactions (ADRs) were observed in 423 (15.0%) patients (incidence [%]): dysgeusia (6.7%), diarrhea (2.6%), taste disturbance (1.5%), nausea (1.2%), vomiting (0.5%), decreased appetite (0.5%), and rash (0.5%). The median times to onset and recovery of these ADRs were 1-2 days and 2-6 days, respectively. Serious ADRs were observed in 6 patients (0.2%). No new safety signals were observed. The study showed that nirmatrelvir plus ritonavir was well tolerated in Japanese patients with COVID-19 in a real-world clinical setting. ClinicalTrials.gov number: NCT05263908.

During the COVID-19 pandemic, Mycoplasma pneumoniae infections were rarely observed in Japan, but a significant outbreak occurred in 2024. At Oita Children's Hospital, a rapid quenching probe polymerase chain reaction (QP-PCR) method was employed to detect the pathogen and to determine the prevalence of macrolide resistance. Between April 1 and September 30, 2024, we tested 679 patients - 462 (68.0%) were positive and 399 (86.4%) were macrolide resistant. The resistance rate was among the highest reported in Japan and comparable to those in neighboring Asian countries. Inpatients were younger than outpatients, and their diagnoses required longer periods of time; corticosteroids were used in 86% of hospitalized cases. QP-PCR detects common A2063G and A2064G mutations and provides results within 40 minutes, which could promote timely therapy, and this is true particularly in the case of younger children whose options could be limited. Early administration of effective antimicrobial agents is crucial for the control of macrolide-resistant M. pneumoniae. These findings indicate that QP-PCR-based diagnostics could significantly contribute to the management and control of M. pneumoniae outbreaks.

We aimed to specify the characteristics of group A Streptococcus M1 (n = 23) or non-M1 (n = 282) isolates from adult (n = 176) and pediatric (n = 129) populations in central Japan, October 2024-April 2025. Of the speA-possessing fourteen non-M1 isolates, there were seven emm3.93 isolates from six non-invasive samples of pediatric patients and one invasive specimen of an adult patient. We found the distribution of M1 clones containing M1_global (n = 1)/M1_13snps (n = 4)/M1_UK (n = 18)-lineages in central Japan of Tokyo/Chiba/Tochigi/Saitama/Kanagawa. The M1 clones were from twenty-one non-invasive samples of pediatric/adult patients and two invasive specimens of adult patients. Additionally, we determined the sic nucleotide alleles and observed the M1_global/M1_13snps/M1_UK sic clustering. Of the CovS amino acid (AA) mutations among M1, there was an insertion of transposase (ISAs1-like IS1548 transposase, 377 AA) into CovS histidine kinase-like ATPase domain (following AA position 458) of one invasive M1_UK isolate. Our observations suggest that CovS AA mutations of invasive isolates with M1_UK should be specified within its four functional domains to evaluate their hypervirulent properties.