Japanese Journal of Infectious Diseases

We estimated the seroprevalence of anti-SARS-COV-2 IgG in different island groups in Okinawa. A cross-sectional sero-survey was repeated in three periods between July 2020 and February 2021. A total of 2683 serum samples were collected from six referral medical centers, each covering a separate region in Okinawa. In the main island, the seroprevalence was 0.0% (0/392, 95% CI: 0.0-0.9), 0.6% (8/1448, 0.2-1.1), and 1.4% (8/582, 0.6-2.7) at the 1st , 2nd , and 3rd sero-survey, respectively. In the remote islands, the seroprevalence was 0...

This study aims to understand the clinical characteristics of severe fever with thrombocytopenia syndrome (SFTS) and screen risk factors for the prognosis. This retrospective study collected the epidemiological, demographic, and clinical and laboratory data of 101 patients with SFTS. Patients were divided into survival and deceased groups, and then logistic regression model was used to evaluate the association between predictors and prognostic variables. A joint detection factor model was constructed, and a receiver operating characteristic (ROC) curve was drawn...

We assessed case fatality rates (CFRs) in cases aged ≥70 years in 10 Japanese prefectures (14.8 million residents) diagnosed between January 2022 and March 2023, when the Omicron variant was dominant in Japan. We selected incident reports on 283,052 study subjects from participating Public Health Centers adhering to the Infectious Diseases Control Law. Cases were passively followed up until the end of their isolation, date of death or 28 days after the COVID-19 diagnosis, whichever occurred first. We calculated age-standardized CFRs with 95% confidence intervals (CI) using the Japanese population aged 70-79, 80-89 and ≥90 in 2022 divided into 16 subgroups according to the period of COVID-19 diagnosis...

In Japan, as elsewhere, the COVID-19 pandemic affected the notification trends of respiratory syncytial virus (RSV) infection. Here, we describe the epidemiological trends of RSV cases among children reported during 2018-2021 in Japan, based on the national surveillance system. Compared to 2018 and 2019, 2020 saw an unprecedented decrease in RSV notifications per sentinel site. However, 2021 experienced an unseasonably early and high peak in week 28 (peak week in 2018 and 2019: week 37) with a large resurgence in notifications, nationwide and across regions...

Clostridium perfringens, which produces C. perfringens enterotoxin (CPE), is a major causative agent of food poisoning owing to its gastrointestinal symptoms. Genotyping is important for identifying the etiological agent in outbreaks of C. perfringens. We attempted to genotype strains isolated from an outbreak of food poisoning in Toyama in 2023 using single nucleotide polymorphism (SNP) analysis. The strains of C. perfringens were isolated from a piece of curry food consumed by all patients and from the feces of the patients and employees...

Escherichia albertii is an emerging foodborne pathogen causing diarrhea. Though various animals, especially poultry, serve as reservoirs, the transmission of E. albertii among reservoirs and the risk to humans remain unclear. This study investigated an E. albertii infected infant with poultry exposure and collected samples from contact persons, poultries, and environment to better understand the transmission dynamics of E. albertii. One E. albertii isolate from contact person, seven isolates from poultries, and six isolates from environment were recovered, respectively...

The maintenance of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) among wildlife populations poses a potential risk for the emergence of novel variants. Therefore, monitoring SARS-CoV-2 infection among animals is crucial. As urban rodents live in close proximity to human habitats, there is concern that they may be a potential source of zoonoses. To examine the prevalence of SARS-CoV-2 in rodent populations, we analyzed 128 serum samples and 129 oral swabs collected from 128 brown rats (Rattus norvegicus) and 2 black rats (Rattus rattus) captured for pest control purposes in Tokyo, Japan, between May and December 2023...

The spread of antimicrobial-resistant organisms (AROs) poses a major threat to animal and human health. In Japan, the estimated disability-adjusted life years (DALYs) due to infections with AROs is 137.9 per 100,000 persons, with methicillin-resistant Staphylococcus aureus (MRSA) being the main contributor. The factors that can contribute to DALYs in Japan include younger age and a higher number of deaths in patients with MRSA bacteremia. Moreover, longer hospital stays may contribute to higher rates of MRSA bacteremia in Japan than in Western countries...

An active epidemiological investigation of COVID-19 cases in the Setagaya ward of Tokyo revealed that household transmission was the main route of infection spread. This study aimed to identify the factors affecting household transmission in patients diagnosed with COVID-19 and their cohabitants, during the wild type virus (December 2020) and alpha variant epidemic (May 2021). Index case factors significantly associated with household transmission for both wild type (WT) and alpha variant (AV), were at least 3 days from onset to diagnosis (WT: risk ratio [RR] 1...

The combination of the four regions of vacA with cagA, cagE, dupA genes and cagA-EPIYA motifs, was studied to find the most likely combination that can be used as a disease determinant marker in Moroccan population. A total of 838 H. pylori positive obtained from consenting patients, that were previously analyzed by PCR to characterize vacA-s -m, -i regions, cagE status and cagA 3' region polymorphism, were used to characterize vacA-d region and to determine dupA gene status. The analysis shows the predominance of the less virulent combination (vacA(s2m2i2d2)dupA(-)cagE(-)cagA(-)), and shows that the risk of gastric cancer is 13...

Hand, foot and mouth disease (HFMD) was one of the most common infectious disease in the past few decades. After 2013, coxsackievirus A6 (CVA6) has replaced enterovirus 71 (EV-A71) and coxsackievirus A16 (CVA16), becoming the predominant pathogen responsible for HFMD in many areas in China. The objective of this study is to investigate the genetic characteristics and molecular epidemiology of CVA6 in Linyi from 2022 to 2023. A total of 965 HFMD cases were enrolled in this study and analyses based on VP1 nucleotide sequences were performed to determine the evolutionary trajectory of CVA6...

The widespread prevalence of extended-spectrum β-lactamase (ESBL)-producing Escherichia coli limits treatment options and is a worldwide problem. The aim of this study was to investigate the antimicrobial susceptibility and ESBL-type of 204 strains of CTX-M-type ESBLs-producing E. coli isolated from 2011 to 2017 in the Chubu region of Japan. Minimal inhibitory concentrations were determined in accordance with the guidelines of the Clinical and Laboratory Standards Institute. Genes encoding CTX-M group β-lactamases were detected by PCR amplification...

Campylobacter jejuni is one of the major bacteria that causes diarrhea in humans. It has been associated with many cases of food poisoning in Japan caused by eating raw or undercooked chicken meat, chicken liver, and grilled chicken (Yakitori). Campylobacter jejuni is also known as the preceding infection pathogen of Guillain-Barré syndrome (GBS), which causes considerable health impact on humans. In January 2022, in a case of C. jejuni food poisoning that occurred at a restaurant in Tokyo, one of four patients with diarrhea developed GBS...

Persistent inflammation in chronic HIV infection may affect immune responses against SARS-CoV-2 infection. Plasma levels of multiple proinflammatory cytokines during acute SARS-CoV-2 infection were assessed in people with HIV (PWH) with effective cART. There were no significant differences in any of the tested cytokines between COVID-19 severity in PWH, while most of them were significantly higher in individuals with severe disease in HIV-uninfected individuals, suggesting that excess cytokines release by hyper-inflammatory responses does not occur in severe COVID-19 with HIV infection...

Clusters of nosocomial coronavirus disease 2019 (COVID-19) were reported globally during the recent pandemic. Unfortunately, these clusters negatively impacted inpatient morbidity, mortality, and hospital functions. Using epidemiological data and whole genome sequencing (WGS) of SARS-CoV-2, the present study investigated an outbreak of COVID-19 at a university hospital. Eight inpatients and 13 healthcare workers tested positive for SARS-CoV-2 during a one-month period. Whole genome sequencing (WGS) of the virus in 11 patients revealed that two variants of concern belonging to the Omicron sublineages, BA...

Hawai'i, the United States' most western geographic state in the Pacific, is intermediate between the North and South American continents and Indo-Pacific regions, including Japan. The Hawaiian Islands' tropical environmental conditions provide favorable ecosystems for various infectious pathogens, their vectors, and reservoirs. This creates a conducive environment for-transmission of various zoonotic diseases that affect both humans and animals. Hawai'i has experienced an increase in outbreaks of dengue, leptospirosis, and murine typhus...

The number of syphilis cases in Tokyo has been found to increase in recent years. We conducted a descriptive epidemiology to elucidate the actual status of syphilis. Data on age, sex, disease stage, and presumed sexual partner of syphilis cases reported in Tokyo were tabulated and analyzed. A total of 9,419 syphilis cases have been reported between 2019 and 2022. There was a particularly sharp rise in the number of reported cases from 2021 to 2022. Comparing 2020 to 2022, the number of syphilis cases among women in their 20s, rapidly increased, more than triple...

Biofilm-producing methicillin-resistant Staphylococcus aureus (MRSA) and coagulase-negative Staphylococci (MR-CoNS) are a clinical challenge for the treatment of healthcare-associated infections. As alternative antimicrobial options are needed, we aimed to determine the effect of curcumin-chitosan magnetic nanoparticles on the biofilm of staphylococcal clinical isolates. MRSA and CoNS clinical isolates were identified by MALDI-TOF mass spectrometry. Antimicrobial susceptibility testing was performed by broth microdilution...

Since the COVID-19 pandemic has affected the epidemiological pattern of pharyngoconjunctival fever (PCF) caused by human adenovirus (HAdV), the prevalence and type distribution of HAdVs associated with PCF among children in Osaka, Japan, between 2019 and 2023 have been analyzed. The number of reported PCF cases in Osaka decreased from 2020 to 2022, followed by an unprecedented increase in 2023. HAdV-C strains, including types C1, C2, and C5, were annually detected in pathogen surveillance in Osaka. HAdV-B3 was not detected for 2 years and 9 months from March 2020, and the number of detections increased from July 2023...

Chronic hepatitis C is a serious condition with relevant public health implications. In Portugal, the prevalence of detectable HCV antibodies is about 0,54%, with higher values in risk groups. Compared to the general population, the prevalence of HCV infection is higher in individuals with psychiatric disorders. There are no studies reporting the prevalence of HCV antibodies in Portuguese psychiatric patients, or in patients with substance use disorders.We carried an observational, prospective study during a period of one year, for patients followed at the Dual Pathology Outpatient and Inpatient Unity of the Coimbra Hospital and University Center, and patients were tested for HCV antibodies...