The potencies of domestic influenza virus reference antigens were initially calibrated using a single radial immunodiffusion (SRID) assay using primarily prepared international reference antigens. The SRID potency should not be affected when using another reference antigen calibrated with the same international antigen. However, the SRID potency of the test antigens can vary, although the causes of these discrepancies remain unclear. Here, we calibrated two candidate reference antigens (LotA and LotB) in the A(H3N2) subtype with various pairs of reference reagent sets (antigen and antiserum). The potencies of LotA and LotB varied depending on the reagent pair used, with a more pronounced effect in LotA (CV = 5.4% vs. 3.8%). To explore the cause of these divergences, we analyzed the dissociation constant of each reagent pair and scored them based on the hypothesis that pairs exhibiting stronger antigen–antibody binding would have smaller precipitin rings. Comparing these scores with the respective potency scores, we observed a strong correlation between the Binding score (relative BLI-K_D) and potency score in LotA (r = 0.8464, p = 0.0001) but not in LotB (r = 0.4000, p = 0.1408). These data suggest that antigen–antibody binding strength is an influencing factor of SRID potency.

Necrotizing fasciitis (NF) is rapidly progressive soft tissue infection with a high mortality rate. Identifying the predisposing factors for NF is critical for enabling diagnosis and medical treatment. This study aimed to identify the factors associated with NF in a hospital located in rural Thailand. In total, 167 NF and 147 cellulitis cases were compared between 2019 and 2021. Among the NF cases, 13.17% required amputation and 7.69% were fatal. The study identified male sex, farming occupation, S. pyogenes infection, and comorbidities, including diabetes mellitus (DM), chronic kidney disease, and hypertension, as significant predisposing factors for NF. DM was statistically significantly associated with an increased risk of amputation. For pathogen-specific NF, advanced age (≥ 60 years) was the only statistically significant predisposing factor for S. pyogenes-associated NF. Conversely, NF caused by Staphylococcus aureus is significantly associated with farming occupation, DM, and hypertension. For NF caused by Enterobacterales, male sex, farming occupation, DM, and chronic kidney disease were statistically significant predisposing factors. These may not be risk factors that can be generalized, but may be the only risk factors for NF in Thailand. However, these findings may inform the development of guidelines for nursing care and pathogen-specific prevention of NF.

Tick-borne viruses are primarily transmitted to vertebrates by infected ticks during blood feeding and cause various diseases in humans and animals. Haemaphysalis longicornis is one of the main tick species responsible for human tick bites and is thought to be the primary vector of severe fever with thrombocytopenia syndrome, an important tick-borne viral disease in Japan. Although H. longicornis ticks pose a potential risk to humans in Japan, studies on tick-borne viral prevalence of this tick species in Japan are limited. In this study, we conducted RNA virome analysis of H. longicornis ticks collected in Toyooka City, Hyogo Prefecture, Japan. Two known viruses, Dabieshan tick virus and Hubei sobemo-like virus 15, and putative novel quaranjavirus-like sequences were detected. Additionally, assessments of endogenous viral elements (EVEs) related to the virus and virus-like sequences suggested putative novel quaranjavirus-like sequences existed in both RNA and DNA forms. However, we could not determine whether this quaranjavirus-like sequence was of viral origin and could not conclude whether the DNA forms of the quaranjavirus-like sequence existed as EVEs in ticks. This study provides new insights into the prevalence of tick-associated viruses in ixodid ticks and serves as a reference for future approaches to prevent tick-borne diseases.

Incompletely resolved immune dysfunction in people living with HIV (PLWH) on antiretroviral treatment (ART) could differentially impact CD4+ and CD8+ T cell subsets. In this study, we investigated SARS-CoV-2 vaccine-induced CD4+ and CD8+ T cell responses in 26 PLWH on ART following third-dose mRNA vaccination. Spike-specific CD4+ and CD8+ T cell responses were assessed based on the expression of activation markers, CD137/OX40 and CD137/CD25, respectively, in response to stimulation with overlapping peptides spanning the spike protein. All participants showed spike-specific T cell responses, with CD8+ responses at a higher median frequency than CD4+. Interestingly, 5 participants who showed a higher frequency of spike-specific CD4+, relative to CD8+ T cells, were significantly younger and had higher CD4 counts pre-ART, in comparison to other participants. Further multivariate analysis revealed that only CD4 count pre-ART was an important predictor of elevated spike-specific CD4+ T cell responses; whereas no association was observed with neutralizing antibody (nAb) potency towards SARS-CoV-2 spike. Our results highlight heterogeneous immune functionality of vaccine-induced, SARS-CoV-2 spike-specific CD4+ and CD8+ T cells in PLHW on ART.

Mpox is a viral zoonosis caused by the monkeypox virus (MPXV), a double-stranded DNA virus mostly transmitted by direct contact, respiratory droplets, and contaminated fomites. Immunodeficiency, younger age, chronic diseases, and lack of immunization are all associated with severe illness. Mpox was declared by the World Health Organization a Public Health Emergency of International Concern on May 20, 2022. This report aimed to provide a detailed histopathological and immunohistochemical findings of a fatal case of an immunosuppressed patient infected with MPXV, reported in Colombia in September 2022. A description of the clinical findings was made, followed by histopathological, immunohistochemical, and molecular studies to confirm the presence of MPXV genomes and viral antigens in different tissues. MPXV viral DNA of the clade IIb was identified, and MPXV genomes were found in the liver, lung, heart, and brain. Interestingly, MPXV antigens were observed in the skin and lung, mainly in necrotic areas surrounded by active inflammatory cell markers. The simultaneous use of several diagnostic tools, as histopathological, molecular and Next Generation Sequencing in fatal cases involving a variety of viral agents, provide relevant information to understand the pathogenesis and clarify the cause of death of this emerging infectious disease.

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. 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.

Currently, the mumps vaccine is not routinely recommended in Japan. Adding the mumps vaccine to the routine vaccination program requires an accurate estimation of the mumps viral infection disease burden. However, no precise estimate exists in Japan because mumps surveillance is sentinel surveillance with a reporting definition consisting of only a clinical diagnosis (parotid swelling). Since parotid swelling can be caused by pathogens other than the mumps virus, the estimation of mumps cases using the current surveillance data is inaccurate. To obtain an accurate burden of disease, we estimated the burden of the disease using the test results performed at a single sentinel site for laboratory-based surveillance during the mumps endemic (Week 14, 2015, to Week 13, 2016) in Kanazawa. The estimated number of mumps cases using laboratory-confirmed cases was 3,881 (95% confidence interval: 3,404–4,357), approximately 1,000 cases less than the estimated number using clinically compatible mumps cases. Although the estimated number of mumps cases using laboratory-confirmed cases was less than that of clinically compatible cases, the frequency of hearing loss due to mumps could potentially be 40% higher than that currently reported. To make the argument for routine mumps vaccination, surveillance using diagnostic testing information is important.

Non-typhoidal Salmonellae (NTS) are one of the significant food-borne pathogens with ≥2600 serovars and diverse range of hosts which significantly increases the chances of infections in humans. Salmonella enterica subsp. enterica serovar Oslo (S. Oslo) is a rare serovar, associated with foodborne illnesses. Here, we aim to report the draft whole genome sequences of S. Oslo ST2344 and ST1370 with reduced ciprofloxacin susceptibility, isolated from clinical samples. Thirty S. Oslo isolates were identified following the standard microbiological techniques. Twenty-six of the thirty (86.66%) S. Oslo isolates were pan-susceptible to the antimicrobials examined, except four isolates, which showed decreased ciprofloxacin susceptibility (MIC 0.12 - 0.50 µg/ml). PFGE analysis showed strains were heterogenous with two sequence types of ST1370 and ST2344 were observed in MLST. The average genome size of the four S. Oslo isolates ranged from 4,760,441 - 5,002,787 bp with average G+C content of 52 %. Different virulence genes encompassing Salmonella Pathogenicity Island (SPI) 1 to 5 linked to disease pathogenesis were found by genome analysis. The draft genome of S. Oslo clinical isolates gives an insight into the molecular characteristics of S. Oslo currently prevalent in India and the phylogenetic analysis sheds light on their evolutionary pattern.

Corynebacterium mucifaciens, usually isolated from sterile human specimens, is a rare Corynebacterium species. We describe a blood-origin C. mucifaciens isolate that was resistant to macrolides/lincosamides and had been isolated from a patient with diabetic gangrene. This isolate formed mucoid colonies harboring a fragment of erm(X). As an initial antimicrobial, piperacillin/tazobactam was intravenously administered to the patient for two weeks. Gangrene debridement resulted in good local management. The clinical course was uneventful. The subculture from blood on a blood agar plate revealed mucoid colonies with a positive string test. Gram staining revealed the presence of a mucoid layer around the coryneform. The minimum inhibitory concentrations determined using broth microdilution method indicated resistance to erythromycin/clindamycin. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS), 16S rRNA gene sequencing, and antimicrobial resistance (AMR) gene profiling were performed. MALDI-TOF-MS identified this isolate as C. mucifaciens based on its high score (2.22). 16S rRNA gene sequencing revealed 99.3% similarity with DMMZ 2278(T) 16S rRNA gene sequence. AMR gene profiling revealed that this isolate possessed a fragment identical to that of erm(X) from Actinotignum schaalii. MALDI-TOF-MS with 16S rRNA gene sequencing can be useful to identify C. mucifaciens when the coryneform shows a mucoid colony appearance with hyperviscosity.

Recently, Staphylococcus argenteus, previously indistinguishable from Staphylococcus aureus, has been recognized as a clinically relevant microorganism because of mass spectrometry. However, despite its clinical significance, limited information is available on S. argenteus. This study evaluated the antimicrobial susceptibility and clinical phenotypes of S. argenteus isolated from clinical specimens. This single-center, retrospective study analyzed cases wherein S. argenteus was detected in clinical specimens obtained at Nagoya City University East Medical Center between April 2023 and April 2024. The organism was identified using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Patient data, including clinical outcomes, were collected and reviewed to classify cases as infections or colonization. S. argenteus was isolated from 23 specimens of 21 patients, with sputum being the most common source (78.3%). Sixty-seven percent of isolates were susceptible to penicillin; 95.2% to erythromycin; and 100% to oxacillin, clindamycin, sulfamethoxazole-trimethoprim, vancomycin, and teicoplanin. Thirteen cases of infection were recorded; pneumonia was the predominant diagnosis (11 cases) in these cases, followed by otitis externa and vertebral osteomyelitis. Most patients were successfully treated with antibiotics, and only one died of S. argenteus pneumonia.

Virologic failure and HIV drug resistance have emerged with the widespread use of antiretroviral therapy (ART). Understanding 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 between January 2014 and December 2018. To determine the cumulative incidence rate of virologic failure and related factors, all PLWHs 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 PLWHs identified, 10,211 PLWHs with primary ART regimens and follow-up data were included. There were 67.1% males, and the mean age was 35 years (SD 11.6). During the median observation period of 0.88 (IQR 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/mm ³ . Active case finding, early ART initiation, and strengthening of the HIV continuum of care intervention are strongly recommended to prevent and reduce treatment failure.

Mycobacterium tuberculosis is the causative agent of tuberculosis. Globally it is one of the most important bacteria responsible for human mortality. To control tuberculosis proper sterilization of Mycobacterium is important. For sterilization of pathogens, sodium hypochlorite is commonly used. However, M. tuberculosis usually shows high resistance against sodium hypochlorite. In this study, we compared the bactericidal activity of chlorous acid and sodium hypochlorite against M. tuberculosis in the presence or absence of artificial saliva. When 7.0 log CFU/mL of M. tuberculosis was treated with different concentrations of sodium hypochlorite or chlorous acid, it was found that while 20,000 ppm of sodium hypochlorite was needed to reduce the pathogen below the detection limit but for chlorous acid only 5 ppm was required. Furthermore, when the experiment was performed in the presence of artificial saliva, 500 ppm of sodium hypochlorite was needed to reduce the M. tuberculosis below detection limit but for chlorous acid it was 25 ppm. The data indicate that chlorous acid is a more powerful disinfectant than sodium hypochlorite regardless of presence or absence of artificial saliva. Thus, chlorous acid may be used as a useful bactericidal agent to sterilize clinical environment contaminated with M. tuberculosis.

The Elecsys^® HCV Duo (HCV Duo) detects anti-HCV antibodies (Duo/anti-HCV) and HCV core antigen (Duo/HCV-Ag), offering an efficient, cost-effective, and rapid HCV screening. 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. 153 untreated CHC patients at Nagoya City University Hospital (NCUH) between 2019 and 2023 were categorized 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.

This research sought to delineate the characteristics of cardiac injury in individuals diagnosed with severe fever with thrombocytopenia syndrome (SFTS) and to ascertain its relationship with prognosis. A retrospective analysis was conducted in 324 patients diagnosed with SFTS between January 2021 and December 2023, patients were categorized into survival and non-survival groups. Univariate and multivariate analyses identified significant indicators and predicted mortality risk factors. Statistically significant differences between the two groups were found in various parameters: age, history of hypertension, presence of diarrhea, petechiae, neurological abnormalities, and numerous laboratory measures. These included lymphocyte, monocyte, and platelet counts, as well as levels of liver enzymes, kidney function markers, cardiac biomarkers, clotting factors, inflammatory markers, Dabie Banda virus RNA, heart rate, PR interval, QT interval and incidence of ST depression. Age, history of hypertension, neurological abnormalities, Cr, PT and QT intervals as independent risk factors for mortality. The incidence of viral myocarditis in patients with SFTS was 64.12%, the non-survival group demonstrated a higher incidence of cardiac injury, which was both earlier and more severe. The incidence of viral myocarditis in patients with SFTS is closely related to the prognosis.

This study evaluated the prevalence of antibodies against eight viruses and pertussis in the serum collected from 191 pregnant women in 2022. Serum IgG antibodies against the following viruses and pertussis toxin (PT) were measured: 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 were simultaneously obtained using a survey questionnaire for vaccine-preventable diseases of measles, rubella, mumps, varicella, and pertussis. Our results were compared with those of our previous studies using umbilical cord blood samples in 2001–2002 and 2013 for eight viruses and a 2016–2018 study for pertussis. Seroprevalence data in 2022 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. The seroprevalence of all diseases, except for PVB19 and pertussis, continued to decline over time. The mean IgG antibody titers were significantly lower and the vaccination coverage rates were significantly higher in four vaccine-preventable viral diseases than previous results. Thus, trends in seroprevalence status for these pathogens should be monitored in pregnant women.

Candida auris (C. auris) was initially isolated from a Japanese patient, and this species is an emerging fungus nowadays owing to its long-term colonization capabilities and high resistance to antifungal drugs. However, accurate domestic epidemiology of C. auris remains unknown. We here collected C. auris isolates reported from hospitals, public health centers, and public health institutes based on the administrative liaison. Moreover, we collected stocked C. auris isolates from three nongovernmental laboratory companies. Seventy C. auris isolates were collected during the study period. C. auris isolates predominantly originated from ear discharge clinical samples. Clade determination based on ITS–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. Whole genome sequencing also confirmed this clade I C. auris isolate. Regarding drug susceptibilities, 20% of isolates were resistant to fluconazole; however, no isolates exhibited polyene or echinocandin resistance. Therefore, C. auris isolates in Japan were generally derived from ear discharges and belonged to clade II. However, ear discharge-derived isolates may not exclusively belong to clade II. Although no invasive cases were reported during the study period, continuing surveillance program for describing clear domestic epidemiology would be necessary.

Updating and evaluating facility-based guidance in cancer centers for managing healthcare personnel (HCP) with close contact with individuals with coronavirus disease 2019 (COVID-19) is challenging because these settings are typically excluded from general guidance, and practical data on this population are limited. This study aimed to describe whether apparent outbreaks occurred under the updated protocol in the real-world setting of a cancer center. From July 2022 to January 2023, 402 HCP who had close contact with an individual with COVID-19 were identified and divided into two groups: the separation group, which underwent a five-day quarantine with physical isolation (172 HCP), and the cohabitation group, which followed a ten-day quarantine (227 HCP). A nucleic acid amplification test (NAAT) was conducted the day before the HCP returned to work. Data from their medical records were retrospectively collected and analyzed. As a primary outcome, no outbreaks due to post-quarantine transmission from close-contacted HCP were observed throughout the study period in either group. Our findings suggested a 5-day quarantine for HCP with close contact with COVID-19 might be applicable in cancer center settings if combined with NAAT before returning to work without increasing the risk of apparent outbreaks.

A measles outbreak occurred in Japan in February 2024 due to a measles virus variant that was imported from central Asian countries with three mismatches at the PCR reverse primer (MVN1213R) annealing site. To examine and improve the impact of real-time PCR effectiveness for detecting this variant, we compared the sensitivity of real-time PCR between MVN1213R and a modified primer using control RNAs, clinical isolates, and clinical specimens. The median difference in the cycle threshold value was 2.92 (interquartile range, IQR 1.99–3.38) lower using the modified primer compared with MVN1213R. Thus, PCR primer sets should be modified to effectively detect this measles virus mutation.

We describe six independent cases of Mesocestoides infection in dogs presenting with diarrhea. Between November 2022 and August 2024, we were consulted by veterinarians regarding the identification of a species of small tapeworm excreted in dog feces. These veterinarians suspected the organism was Echinococcus multilocularis and believed it should be reported to health centers as a notifiable disease. Segmented and unsegmented worms, approximately 600 to 1,400 µm in length, were recovered from fecal samples. Microscopically, the worms had four suckers on the scolex but no rostellum. Subsequent molecular analysis of the mitochondrial cox1 and 12S rDNA genes revealed that all cases involved Mesocestoides vogae. Affected dogs were treated with an anthelmintic, and the diarrhea disappeared immediately. Perhaps due to the heavy infection load, the host animals developed diarrhea, and the parasite was likely expelled before reaching maturity. These small tapeworms with few proglottids could therefore confuse veterinarians.

Monkeypox is a zoonotic viral disease caused by monkeypox virus infection and formerly this disease had been endemic mainly in Africa. Since May 2022, the disease has rapidly spread across the world and some imported case was confirmed sporadically in China. Under these circumstances, data of confirmed cases were collected consecutively in Chengdu, southwest China to investigate clinical and epidemiological characteristics. In this study, 28 male patients were confirmed to have monkeypox infection, with 26 identifying as MSM (men who have sex with men). Typical lesions included papules, pustular papules, vesicles, scabs and ulcerations. The most common sites of skin lesions were anogenital and perineal areas, three patients developed a widespread exanthem. Seven patients reported a history of sexual transmitted diseases, no one was hospitalized and there were no deaths. Three instances of secondary transmission were identified among close contacts, all of them were sexual partners of our participants. Furthermore, this observation provides insights of the public health for surveillance of this emerging disease and raises awareness among people at risk.

An external quality assessment (EQA) on nucleic acid amplification tests for SARS-CoV-2 was conducted among clinics that introduced testing instrument through the Tokyo Subsidy Program for Facilities and Equipment for Testing in COVID-19 in 2023. The survey samples consisted of sample 1 (20,000 copies/mL), sample 2 (10,000 copies/mL), and negative sample. Results were obtained through Cycle threshold (Ct) values as well as positive-negative result determinations. On-site technical support was provided to the clinics that responded incorrectly. A total of 544 clinics (589 instruments) participated, and Abbott’s ID NOW ^TM (82.2%) was the most widely used in this survey. The qualitative test results showed high correctness rates, 95.2% for sample 1, 93.2% for sample 2, and 96.3% for negative sample. Differences in Ct values were observed among reagents and instruments. Technical support were provided to 63 clinics. It revealed that discrepancies of qualitative test were mainly due to deviations from the protocol instructions, mixing all three survey samples into one vial and errors caused by foaming. This survey was unique in that the participants were mostly end-users who were not laboratory testing specialists and mainly used point-of-care testing instruments. It is important to continue EQA to improve and maintain testing accuracy.

Recombinant human adenoviruses (HAdVs) have been reported from many countries, including Japan. We report a recombinant HAdV-C type detected in feces with gastroenteritis infection or throat swabs with upper respiratory tract inflammation of six children in Aichi Prefecture. This type may have been prevalent in the area. Between April 2014 and March 2019, we attempted to detect HAdVs in 9,483 specimens (fecal, throat swab, urine, and conjunctival swab) collected from patients with suspected viral infection. A total of 220 HAdV-C isolates were obtained and serotyped by neutralization test (NT). Of these, 62 HAdV-C strains (HAdV-C1: 15, -C2: 19, -C5: 22, -C6: 6) were genotyped by sequencing for the three regions, penton base, hexon, and fiber regions, respectively. All 62 strains were grouped into the same genotype as serotype for the hexon and fiber region. In contrast, phylogenetic analysis showed 6 of the 22 strains with serotype HAdV-C5 were grouped into HAdV-C89 for the penton base region. This type was detected as a recombinant HAdV causing SARI in China between 2017 and 2021, was found to have been persistently detected in transnational Aichi Prefecture over the same period.

Hepatitis A virus (HAV) and hepatitis E virus (HEV) are thought to have similar routes of transmission and epidemiology in developing countries. This study investigated the seroprevalences of these pathogens among healthy individuals in the Dhanusha district of Madesh Province, Nepal. Ninety serum samples collected between 2022 and 2023 were analyzed by enzyme-linked immunosorbent assay to detect immunoglobulin (Ig)G antibodies against HAV and HEV. Individuals (median age, 23 years; range, 1–45 years) were sorted into five age groups: 1–10, 11–20, 21–30, 31–40 and 41–45 years. Prevalences of HAV and HEV IgGs were 96.7% and 13.3%, respectively. All age groups showed very high positivity rates for HAV antibodies. In contrast, HEV infection rates were extremely low in children, and rapidly increased in adults >31 years old. No significant correlation was found between HAV and HEV seropositivity. Additional studies including other areas in Nepal are required for nationwide sero-surveillance against HAV and HEV.

MinION sequencing is widely used to sequence influenza A virus (IAV) genomes; however, the accuracy and utility of this approach, using the latest chemistry to obtain whole viral genome sequences directly from clinical samples, remain insufficiently investigated. We evaluated the sequencing accuracy of combining simultaneous multisegment one-step RT-PCR and MinION sequencing using various subtypes of 13 IAV isolates. The latest R10.4.1 chemistry significantly improved sequencing accuracy, achieving ≥99.993% identity with Illumina MiSeq results and reducing the single nucleotide deletion in homopolymer regions. Applying this method to 11 clinical samples enabled rapid subtype identification and the acquisition of eight full-length IAV genomes. In four of these samples, subtype identification of HA and NA was achieved within 20 min after the start of sequencing and a full-length IAV genome was obtained within 7 h after RNA extraction. However, there was concern that cross barcode misassignment during demultiplexing affected data interpretation, particularly for samples with low viral genome copy numbers. This approach can be used for the rapid identification of IAV subtypes and accurate acquisition of full IAV genome sequences from clinical samples, although careful data analysis is required for the multiplex sequencing of clinical samples with low viral genome copy numbers.

Ticks are vectors of tick-borne diseases (TBDs) between humans and wild vertebrates. The relationship between ticks, host vertebrates, and their pathogens should be investigated for the effective control of TBDs. Hence, this study aimed to detect vertebrate DNA in ticks by using molecular methods and identify the species of such ticks collected in Fukuoka Prefecture, which is located in the northern Kyushu area of Japan. Ticks from vegetation were collected by flagging from 2017 to 2023. Out of 152 ticks collected by flagging, 65 (42.8%) were found to have vertebrate DNA. By stage, vertebrate DNAs were detected in 26 of 83 nymphs (31.3%) and 39 of 69 adults (56.5%). Among the host vertebrates, Sika deer was the main blood-feeding source of ticks in Fukuoka Prefecture. Owing to the widespread of deer across this prefecture, control of its population and other wildlife populations could be a countermeasure of reducing TBD risk.

Early and accurate diagnosis of leprosy is important but remains a significant challenge till date. Loop-mediated isothermal amplification (LAMP) is an isothermal process for amplification of nucleic acids at constant temperature and has been used to develop field-friendly tests for many diseases. In the present study, we have described the development of a colorimetric LAMP assay targeting Mycobacterium leprae-specific 450 bp conserved region of the repeat sequences known as RLEP. Furthermore, the amplicons of LAMP were subjected to restriction analysis by the enzyme EcoRV for specificity. This method has the potential to become an accurate and efficient alternative to Sanger sequencing which is currently in use to validate the RLEP amplified products.

Guidelines for sexually transmitted infections recommend oral metronidazole (MNZ) as the first-line treatment option for vaginal trichomoniasis; however, there have been cases of prolonged symptoms or recurrence after treatment. To consider appropriate treatment strategies for refractory vaginal trichomoniasis, we conducted a retrospective cohort study. We reviewed the medical records of patients who tested positive for Trichomonas vaginalis (T. vaginalis) at the National Center for Global Health and Medicine between August 2011 and May 2023. Refractory vaginal trichomoniasis was defined as the failure after the initial MNZ treatment. During the study period, nine cases of vaginal trichomoniasis were identified, six of which were refractory to treatment for T. vaginalis. Four patients were cured with a combination of oral and vaginal tinidazole (TNZ) therapy, one with oral TNZ and one with two doses of MNZ. Possible causes of treatment failure include MNZ-resistant T. vaginalis, reinfection between partners, and infections of other sexual transmitted diseases. However, the fact that TNZ was effective suggests that MNZ-resistant T. vaginalis may have been the cause. Although MNZ resistance testing was not performed in this study, treatment with TNZ should be considered in cases of refractory vaginal trichomoniasis, possibly caused by MNZ-resistant T. vaginalis.

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has repeatedly undergone mutations since its emergence, based on which it has been assumed that there was a change in its characteristic, including virulence or antigenicity. In this study, we investigated the viral load in the nasopharyngeal samples of patients with SARS-CoV-2 in Gunma prefecture, Japan, from April 2, 2020, to April 1, 2023. The amount of virus in samples in the Omicron-variant-prevalent period was higher than that of strains detected in samples before week 50 of 2020, the B.1.1.284-prevalent period, the Alpha-variant-prevalent period, and the Delta-variant- prevalent period. Moreover, among Omicron variants, the sublineage BA.5-prevalent period showed higher amount of virus in the samples than BA.1-prevalent period and BA.2-prevalent period. Hence, the new variant may have been able to release more viruses into the nasopharyngeal samples during the process of repeated mutations, resulting in widespread infection. The amount of virus detected in the nasopharyngeal samples showed an increasing tendency with the evolution of the virus. Therefore, considering that the amount of virus in specimens is also vital factor contributing to the spread of infection, it is important to examine this factor in samples.