Japanese journal of infectious diseases最新文献

The COVID-19 mortality seemed to be higher in high-income/hygienic countries; this is contrary to conventional communicable diseases which usually occur in low-income countries. Another characteristic of COVID-19 is that some proportions of the infected persons had no symptoms but transmitted the virus to others. In this paper, the author proposes a hypothesis that infected but asymptomatic persons produce two kinds of infectious respiratory particles (IRP) by speaking: large droplets and small aerosols. The large droplets are produced from the saliva by pronouncing a plosive, /p/ or /t/; and the small aerosols are produced from the laryngeal exudate by vibration of vocal cords for voicing of vowels. The heavy droplets collide with the face of other persons in conversation, resulting in droplet infection. In contrast, the lighter aerosols float in the air, accumulate inside an airtight room after a longer talking, and cause airborne infection in other persons staying in the same room. Then, the author discusses on the COVID-19 global epidemiology, which may have depended on 1) climate and housing structure, 2) cultural behaviors, and 3) languages among different countries.

Coronavirus disease 2019 (COVID-19) clusters are serious 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 pre- and post-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 were analyzed in the study participants using 'Pomegraph', a newly developed integrated graphical tool, in combination with epidemiological and genome information. Our findings showed that although the viruses were the same XBB subvariants of SARS-CoV-2 Omicron XBB.1.5 and XBB.1.16, 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 pre- and post- 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 amounts of antibodies and neutralizing antibody titers, which is difficult to determine in general clusters. Our results facilitated the analysis of cluster factors such as pathogens, susceptible persons, 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 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.

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 by 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, erythrocytes, urinary proteins, and hemoglobin (all P < 0.05), while platelet counts were lower (P < 0.05). Multivariable logistic regression analysis revealed that monocyte count and hemoglobin were independent predictors of HFRS. The area under the ROC curve (AUC) for the combined use of monocyte count and hemoglobin 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 hemoglobin 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.

This report analyzes a measles outbreak that occurred at a medical institution (Hospital A) in Gyeonggi-do in April 2024, aiming to examine its epidemiological characteristics and derive implications for disease control policies. A cross-sectional study was conducted on 469 confirmed cases and contacts associated with Hospital A during the outbreak period using telephone interviews and on-site epidemiological investigations. A frequency analysis of epidemiological data was performed using statistical software. The attack rate related to the outbreak at Hospital A was 0.64%, with a secondary attack rate of 25.0%. The outbreak involved three confirmed measles cases, including one patient (index case) and two healthcare workers (secondary cases), all carrying the B3 genotype. In total, 469 individuals were exposed during the outbreak at Hospital A, including the three confirmed cases. The outbreak likely originated from a hospital visitor as the source of infection, with no additional transmission beyond hospital staff. To prevent transmission, prompt contact management, periodic antibody testing, and additional vaccinations for staff are recommended.

Candida auris was initially isolated from a Japanese patient, and is now an emerging fungus species owing to its long-term colonization capabilities and high resistance to antifungal drugs. However, the domestic epidemiology of C. auris in Japan remains unknown. In this study, we collected C. auris isolates from hospitals, public health centers, and public health institutes in Japan based on the administrative liaison. Moreover, we also obtained isolates from three nongovernmental laboratory companies. Seventy C. auris isolates were collected during the study period. These isolates predominantly originated from clinical ear discharge samples. Clade determination based on the internal transcribed spacer-D1/D2 regions and CauMT1 locus revealed that almost all isolates belonged to clade II; however, one ear discharge-derived isolate belonged to clade I, confirmed by whole genome sequencing. Regarding drug susceptibility, 20% of the isolates were resistant to fluconazole; however, none of the isolates exhibited polyene or echinocandin resistance. In summary, the C. auris isolates collected in Japan were generally derived from ear discharge samples and belonged to clade II. However, ear discharge-derived isolates may not belong exclusively to clade II. Although no invasive cases were reported during the study period, continuing surveillance programs to clearly describe the domestic epidemiology is necessary.

Virologic failure and HIV drug resistance have emerged with the widespread use of antiretroviral therapy (ART). An understanding of these predictors is the basis for prevention strategies to achieve a high treatment success rate. A retrospective cohort study was conducted among antiretroviral-naïve people living with HIV (PLWH) registered in the national AIDS program database of the National Health Security Office Region 4, Thailand, between January 2014 and December 2018. To determine the cumulative incidence rate of virologic failure and related factors, all PLWH were monitored for viral load status through December 2019. Virologic failure was defined as HIV viral load >1,000 copies/mL after 6 months of ART. Of the 42,229 PLWH identified, 10,211 PLWH with primary ART regimens and follow-up data were included. There were 67.1% males, and the mean age was 35 years (standard deviation: 11.6 years). During the median observation period of 0.88 years (interquartile range: 0.23-1.94 years) after ART initiation, 2.4% (242/10,211) of the PLWH experienced virologic failure. The Cox proportional hazard model revealed that the risk of developing virologic failure was significantly associated with age <30 years and baseline CD4 cell count ≤200 cells/mm³ . Active case finding, early ART initiation, and strengthening of the HIV continuum of care intervention are strongly recommended in order to minimize treatment failure.

The Elecsys ^® HCV Duo (HCV Duo) detects antibodies to HCV (Duo/anti-HCV) and HCV core antigen (Duo/HCV-Ag), offering an efficient, cost-effective, and rapid way to screen for hepatitis C virus (HCV). We evaluated HCV Duo's utility in Japan. We analyzed 373 samples (120 HCV RNA-detectable and 253 HCV RNA-undetectable) from chronic hepatitis C (CHC) patients. Duo/anti-HCV sensitivity was assessed using conventional assays. Duo/HCV-Ag sensitivity and specificity were evaluated based on HCV RNA levels. We categorized 153 untreated CHC patients at Nagoya City University Hospital (NCUH) between 2019 and 2023 by HCV RNA levels. HCV Duo showed 100% sensitivity (373/373) for Duo/anti-HCV and 99.2% specificity (251/253) for Duo/HCV-Ag in resolved infection. Duo/HCV-Ag exhibited 55.0% sensitivity (66/120) in active HCV infections. For HCV RNA levels ≤4.0, 4.1-5.5, and ≥5.6 log IU/mL, Duo/HCV-Ag detection rates were 20.5% (9/44), 33.3% (7/21), and 87.3% (48/55), respectively. At NCUH, 71.2% (109/153) of patients had HCV RNA levels ≥5.6 log IU/mL, while 2.6% (4/153) and 26.1% (40/153) had levels ≤4.0 and 4.1-5.5 log IU/mL, respectively. Duo/HCV-Ag performance improves with higher HCV RNA levels, particularly ≥5.6 log IU/mL. HCV RNA testing is recommended for patients positive for Duo/anti-HCV but negative for Duo/HCV-Ag. Duo/HCV-Ag-positive patients should be referred to hepatologists for further evaluation and treatment.

Monkeypox is a zoonotic viral disease caused by monkeypox virus infection, which is endemic to Africa. Since May 2022, the disease has rapidly spread worldwide, and imported cases have been sporadically confirmed in China. Given these circumstances, data on confirmed cases were collected consecutively in Chengdu, Southwest China, to investigate their clinical and epidemiological characteristics. In this study, 28 male patients were confirmed to have monkeypox infection, with 26 men who had sex with men. Typical lesions included papules, pustular papules, vesicles, scabs, and ulcers. The most common sites of skin lesions were the anogenital and perineal areas, and three patients developed widespread exanthem. Seven patients reported a history of sexually transmitted diseases, none of whom was hospitalized, and there were no deaths. Three instances of secondary transmission were identified among close contacts, all of whom were the sexual partners of the participants. Furthermore, this observation provides insights into public health for the surveillance of this emerging disease and raises awareness among at-risk individuals.

This study evaluated the prevalence of antibodies against eight viruses and pertussis in serum samples collected from 191 pregnant women in 2022. Serum IgG antibodies were measured against the following viruses and pertussis toxin (PT): measles virus (MV), rubella virus (RV), mumps virus (MuV), varicella-zoster virus (VZV), herpes simplex virus (HSV), cytomegalovirus (CMV), Epstein-Barr virus (EBV), and human parvovirus B19 (PVB19). Infection history and immunization status for vaccine-preventable diseases, including measles, rubella, mumps, varicella, and pertussis, were simultaneously obtained via a questionnaire. Findings were compared with those of our previous studies using umbilical cord blood samples from 2001-2002 and 2013 (eight viruses) and from 2016-2018 (pertussis). In 2022, seroprevalence rate were 88.5% for MV, 86.4% for RV, 46.1% for MuV, 91.1% for VZV, 47.6% for HSV, 61.3% for CMV, 93.7% for EBV, 69.6% for PVB19, and 63.4% for PT. Seroprevalence declined over time for all diseases except PVB19 and pertussis. Mean IgG antibody titers were significantly lower, despite significantly higher vaccination coverage rates in the four vaccine-preventable viral diseases than in previous studies. Therefore, ongoing monitoring of seroprevalence trends for these pathogens in pregnant women is essential.