Cyclospora cayetanensis, a food and waterborne pathogen, is responsible for prolonged diarrheal illness. This study aimed to investigate the prevalence, risk factors, and seasonal patterns of C. cayetanensis infection among diarrheal patients in eastern India. A hospital-based cross-sectional study was conducted. The overall prevalence of C. cayetanensis in the study region was determined to be 2.11%. The highest incidence (7%) was observed during the monsoon months, particularly in July and August. Children aged >5–12 years were the most susceptible group (17.8%, odds ratio [OR] = 47.45, P-value [P] < 0.0001). Individuals from households lacking proper sanitation or from rural areas showed a higher burden of infection. A statistically significant association between infection and contact with animals was also found (3.45%; OR = 2.81; P < 0.0001). Symptomatic individuals predominantly experienced profuse diarrhea with abdominal cramps. Coinfection with soil-transmitted helminths (STHs) was found to be most common in Cyclospora positive cases. Limited genetic diversity of Cyclospora was found within the population, with 6 haplotypes circulating in the region. Overall, this study highlights the public health risk posed by C. cayetanensis in eastern India. We recommend including Cyclospora detection in routine laboratory diagnoses to prevent its spread. Raising awareness of hygiene and implementing rigorous control measures will prove effective in the eradication of Cyclospora from this endemic country.

To explore the clinical value of routine laboratory tests in the early diagnosis of hemorrhagic fever with renal syndrome (HFRS), this study retrospectively analyzed the medical records of 146 patients, including 87 HFRS cases and 59 controls. Subsequently, a multivariable logistic regression model was employed to identify clinically relevant indicators for HFRS diagnosis. The sensitivity and specificity of these indicators were further evaluated using receiver operating characteristic (ROC) curve analysis, both individually and in combination. Results showed that HFRS patients had significantly higher levels of leukocytes, neutrophils, lymphocytes, monocytes, eosinophils, basophils, red blood cells, urinary proteins, and hemoglobin (Hb) (all P < 0.05), while platelet counts were lower (P < 0.05). Multivariable logistic regression analysis revealed that monocyte count and Hb were independent predictors of HFRS. The area under the ROC curve (AUC) for the combined use of monocyte count and Hb level in diagnosing HFRS was 0.942, which was significantly higher than the AUC when either was used alone, indicating excellent predictive performance. In conclusion, elevated monocyte count and Hb levels are independent predictors of HFRS. Their combined use enables effective prediction of HFRS and may serve as a key criterion for the early diagnosis of HFRS in primary care settings.

Coronavirus disease 2019 (COVID-19) clusters pose a serious risk for older adults in nursing homes. Several studies have analyzed patient epidemiology and trends in blood antibody titers after COVID-19 cluster outbreaks, but few comparative analyses of the periods both before and after cluster outbreaks have been reported. This study aimed to investigate epidemiological surveys and whole-genome sequences of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in clinical specimens following a COVID-19 cluster occurrence in a nursing home. Routes and modes of infection among the study participants were analyzed using “Pomegraph,” a newly developed integrated graphical tool, in combination with epidemiological and genome information. Our findings showed that, although all the viruses belonged to the Omicron XBB.1.5 or XBB.1.16 subvariants of SARS-CoV-2, they were imported from three different locations, based on the genome sequences. We evaluated the amount of antibodies and neutralizing antibody titers in the participants’ sera before and after the cluster outbreak. Before the cluster outbreak, no significant differences were observed between infected and uninfected participants in the period after vaccination or in the levels of antibodies and neutralizing antibody titers, which are difficult to determine in investigations of general clusters. Our results facilitated the analysis of cluster factors, such as pathogens, susceptible individuals, and transmission.

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 14 speA-possessing non-M1 isolates, there were seven emm3.93 isolates from 6 non-invasive samples of pediatric patients and 1 invasive specimen of an adult patient. We found the distribution of M1 clones containing M1_global (n = 1), M1_13snps (n = 4), or M1_UK (n = 18) lineages in the central Japan region consisting of Tokyo, Chiba, Tochigi, Saitama and Kanagawa. The M1 clones were from 21 non-invasive samples of pediatric/adult patients and 2 invasive specimens from 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 the CovS histidine kinase-like ATPase domain (following AA position 458) of one invasive M1_UK isolate. Our observations suggest that CovS AA mutations in invasive isolates with M1_UK should be specified within the four functional domains of CovS to evaluate their hypervirulent properties.

Staphylococcus argenteus is a novel bacterial species distinct from Staphylococcus aureus. Nevertheless, S. argenteus is often misidentified as S. aureus because they cannot be differentiated easily using routine diagnostic microbiology methods. An 81-year-old man was admitted because of persistent lumbar pain and fever. Strains from his blood cultures were initially identified as methicillin-susceptible S. aureus. Enhanced computed tomography revealed an erector spinae abscess connected with the L5 transverse process, and magnetic resonance imaging of the lumbar region showed a high intensity of L1 and L5 on short tau inversion recovery. The abovementioned pathogen was also cultured from the aspiration fluid of the abscess. Therefore, the patient was diagnosed with vertebral osteomyelitis with an erector spinae abscess. We analyzed the detected strain using matrix-assisted laser desorption ionization time-of-flight mass spectrometry and whole-genome sequencing, re-identifying the strain as S. argenteus sequence type (ST) 1223. Although S. argenteus ST1223 has mainly enteric pathogenicity, our case suggests its potential to invade the musculoskeletal system. Its pathogenicity was similar to or greater than that of S. aureus in both previous studies and our case. Therefore, the clinical differentiation of S. argenteus and S. aureus warrants further investigation.

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 where HRV was detected. The facility housed 47 residents, 31 of whom developed symptoms. Of those, 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 HRV-C type 56. 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.

Epidemics of respiratory syncytial virus (RSV) infection previously followed a predictable and seasonal pattern. However, the emergence of COVID-19 and the accompanying public health measures disrupted RSV seasonality worldwide. To investigate the long-term epidemiological impact, we analyzed weekly RSV-related hospitalizations in children under 15 years of age from 2018 to 2024 in Saitama Prefecture, Japan. During the COVID-19 pandemic, RSV admissions notably declined in 2020, but the number of hospitalizations returned to pre-pandemic levels. The peaks of admission rates occurred in March, in both 2023 and 2024, which were earlier than the August peaks seen in 2018 and 2019. We also found that the proportion of hospitalized patients aged ≥2 years increased notably to 30% in 2021 and 2022, and declined to 21.2% in 2024. Although an upward trend in intubation rates was observed, no statistically significant differences were found. These findings suggest that the COVID-19 pandemic led to earlier RSV outbreaks and temporary shifts in age distribution. It remains unclear whether RSV seasonality and age patterns will return to their pre-pandemic status. Ongoing surveillance is essential to better predict future outbreaks and inform optimal timing for preventive interventions, such as vaccination or monoclonal antibody administration.