Anisakidosis is developed by ingesting Anisakis in marine fish, including the chub mackerel, Scomber japonicus, without proper pre-treatment such as cooking or freezing. Two sibling species of Anisakis are found in S. japonicus from Japanese waters, and the prevalence and species of Anisakis in the fish depend on the sea area. For example, Anisakis simplex sensu stricto (s.s.) is found in the Pacific stock of S. japonicus, whereas A. pegreffii is found in the Tsushima Warm Current stock. S.japonicus caught in the Bungo Channel, off the coast of Saganoseki in Oita Prefecture, which is branded as Sekisaba, inhabits a very limited area; however, the infection states of Anisakis found in Sekisaba remain unclear. In this study, we compared the infection states of Anisakis in Sekisaba with those in S. japonicus caught in the South Oita area and Nagasaki Prefecture. All Anisakis from the Nagasaki Prefecture were A. pegreffii, while most of them found in Sekisaba and fish from the South Oita area were A. simplex s.s. Interestingly, the prevalence of Anisakis in Sekisaba was significantly lower than that in the other two areas. This may reflect the fact that Sekisaba might belong to a distinct stock of S. japonicus, varying from other stocks.

We aimed to assess the rate and risk factors of postoperative complications following tooth extraction in HIV-infected patients by CD4 count. The study participants were 231 HIV-infected patients who underwent tooth extraction at our institution between January 2007 and December 2011. Blood test results, underlying diseases, surgical site, extraction method, and postoperative complication data were obtained from medical records. Potential risk factors of postoperative complications were analyzed using multivariate logistic regression. Patients were divided into two groups: 61 (26%) patients with a CD4 count < 200/μL, and 170 (74%) with a CD4 count ≥ 200/μL. Of the 231 patients, 12 (5.2%) developed postoperative complications (alveolar osteitis, n = 10; surgical site infection, n = 2). The rate of complications did not differ between the CD4 < 200/μL group (1.6%) and the CD4 ≥200/μL group (6.5%) (adjusted odds ratio [aOR]: 9.328, 95% confidence interval [CI]: 0.470, 185.229; P = 0.1431). Surgical extraction with bone excavation, but without CD4 count, was identified as a risk factor for post-extraction complications (aOR: 22.037, 95% CI: 1.519, 319.617; P = 0.0234). A low CD4 count is not a risk factor for post-extraction complications in patients with HIV infection. We conclude that tooth extraction should be performed based on dental/oral conditions, and not delayed until CD4 count improvement.

Tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis (Tdap) vaccine is generally used for booster vaccination of infants in Europe and the United States to avoid increased reactogenicity after diphtheria and tetanus toxoids and acellular pertussis (DTaP) vaccination. However, Japan has extended the use of additional DTaP vaccination without reducing the antigen dose for diphtheria and pertussis in adolescents and adults, despite limited reports on its safety in adults. This prospective, observational, questionnaire-based study investigated the occurrence of adverse events (AEs) following DTaP vaccination between June 2018 and June 2019 in participants aged 10 years or older. Of the 250 eligible participants, 235 (94%) responded regarding AEs. Among them, 133 (56.6%) reported AEs, of which 39 reported systemic AEs (16.6%) and 120 reported local AEs (51.1%) attributed to DTaP vaccination. The incidence of local AEs was markedly higher with DTaP vaccination than with non-DTaP vaccination (51.1% vs. 10.5%), and AEs appeared later (P < 0.01) and lasted longer (P < 0.01) with DTaP vaccination. However, more than 75% of these AEs resolved within 7 days. DTaP vaccination was not associated with any serious AEs. These results indicate that the DTaP vaccine can be widely used as a booster in adults as an alternative to the Tdap vaccine.

We aimed to clarify the status of hand hygiene practices among ordinary citizens during the COVID-19 pandemic in Japan, as well as the frequency of daily hand hygiene as an indicator of education and evaluation. This cross-sectional study was based on an internet survey completed by 2,149 participants (age range: 20–79 years, men: 51.0%, response rate: 89.5%), selected from June 23 to 28, 2020. The participants responded regarding the frequency of implementing hand hygiene at 5 moments (after returning from a public place, after using the toilet, after touching something outside, before eating food, and after blowing the nose, coughing, or sneezing). Additionally, the participants responded to the number of daily hand hygiene events. The cutoff value of the total number of daily hand hygiene events to determine whether hand hygiene was performed at all 5 time points was determined using receiver operating characteristic analysis. The mean number of hand hygiene events was 10.2 times/day. The prevalence of implementing hand hygiene at each moment ranged from 30.2% to 76.4%; only 21.1% of respondents practiced hand hygiene at all times. Both Youden Index and specificity were high when the cut-off value was 11 times/day. Therefore, the criterion of hand hygiene (≥11 times/day) may be useful in education and evaluation.

Several outbreaks of trench fever caused by Bartonella quintana occurred in soldiers during World Wars I and II. Although trench fever cases have been decreasing worldwide, the disease was reported among the homeless population in developing and developed countries. The current prevalence of B. quintana infection in Japan is unclear. Blood and body louse (Pediculus humanus humanus) samples were obtained from homeless inpatients with body lice during emergency hospitalization in Tokyo from January 2013 to March 2015. Patients were tested for B. quintana infections using the culture method, polymerase chain reaction, and indirect immunofluorescence assay (IFA). Among the 29 patients tested, the presence of Bartonella spp. was confirmed by genomic sequencing of DNA extracted from two samples from blood culture performed for 15 out of 29 patients and from body louse samples of 20 patients (69%). Immunoglobulin G against B. quintana was detected in 10 patients (34.5%) at a cut-off titer of 1:256 in IFA. B. quintana infection was detected in samples obtained between 2013 and 2015 in Tokyo and needs to be on the list of differential diagnoses performed for febrile homeless individuals.

We retrospectively studied nasopharyngeal severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) viral load in coronavirus disease 2019 (COVID-19) patients who were hospitalized between January 13 and April 1, 2020. Quantitative real-time reverse transcription-polymerase chain reaction (RT-PCR) was conducted using primers and probes targeting the ORF1ab and N genes. All patients were classified in the following groups: Group 1: received favipiravir + chloroquine or hydroxychloroquine + lopinavir/ritonavir or darunavir/ritonavir for 5–10 days, Group 2: received chloroquine or hydroxychloroquine + lopinavir/ritonavir or darunavir/ritonavir for 5–10 days, and Group 3: no antiviral medication. Among the 115 patients, 38 (33%), 54 (47%), and 23 (20%) were in Groups 1, 2, and 3, respectively. The median (IQR) baseline viral loads on day 0 of Groups 1, 2, and 3 were 7.2 (6.0–8.1), 6.9 (5.8–7.8), and 6.9 (5.8–7.6) log₁₀ copies/mL, respectively. The reductions of mean viral loads on day 3 from baseline were 2.41, 1.38, and 2.19 log₁₀ copies/mL in the corresponding groups (P < 0.05). There were no differences in the reduction of mean viral loads from baseline among the three groups on days 5 and 10 (P > 0.05). Multiple logistic regression analysis showed that receiving favipiravir was associated with nasopharyngeal viral load reduction at three days (P = 0.001). Significant nasopharyngeal SARS-CoV-2 viral load reduction was achieved in COVID-19 patients who received a favipiravir-containing regimen.

Green tea extracts effectively inactivated severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in vitro in a dose-dependent manner. Ten-fold serially diluted solutions of catechin mixture reagent from green tea were mixed with the viral culture fluid at a volume ratio of 9:1, respectively, and incubated at room temperature for 5 min. The solution of 10 mg/mL catechin reagent reduced the viral titer by 4.2 log and 1.0 mg/mL solution by one log. Pre-infection treatment of cells with the reagent alone did not affect viral growth. In addition, cells treated with only the reagent were assayed for host cell viability using the WST-8 system, and almost no host cell damage by the treatment was observed. These findings suggested that the direct treatment of virus with the reagent before inoculation decreased the viral activity and that catechins might have the potential to suppress SARSCoV-2 infection.

Human immunodeficiency virus (HIV) infection in pregnancy may result in adverse obstetric outcomes, such as stillbirth. The present study aimed to compare the stillbirth rate (SBR) in HIV-infected pregnant women with that in the general population, observing the year-wise trends of HIV infection-associated SBR and identifying possible associated exposures. A retrospective cohort study was conducted through the analysis of secondary data from 314 integrated counseling and testing centers across the state of West Bengal, India, from 2012 to 2020. A total of 3,478 HIV-infected pregnant women were followed up, and year-wise SBR trends were compared with that among all pregnancies of the state as per the latest available Sample Registration System report in India. A linear regression analysis of the year-wise trend in SBR was performed. T-test of two means and the relative risk (RR with 95% confidence interval) was conducted to identify the associations between different exposures and stillbirth. The SBR was significantly higher (26.7/1,000) in HIV-infected pregnancies than in all pregnancies (5/1,000) and was significantly reduced after the initiation of antiretroviral treatment (RR = 0.09: 0.05–0.16). Spouse testing for HIV (surrogate marker for familial involvement) (RR = 0.35: 0.20– 0.61) and maternal literacy (RR = 0.62: 0.40–0.97) were also found to be significantly effective in preventing stillbirth.

The domestic combined measles-mumps-rubella (MMR) vaccine was withdrawn in Japan in 1993 following an outbreak of aseptic meningitis attributed to the mumps component of the cocktail. KM-248 is an MMR vaccine (M-M-R^®II), manufactured by Merck & Co., Inc. (Kenilworth, NJ, USA) and registered and approved in 74 countries, but which has not been approved in Japan. This multicenter, randomized, single-blind study, was designed to evaluate the noninferiority of the KM-248 measles component in terms of immunogenicity when compared to the control measles vaccine already approved in Japan and the seroconversion rates for these three viruses following KM-248 administration. Vaccination with KM-248 in children aged 12–90 months (n = 178) induced robust immune responses to measles, mumps, and rubella viruses. The seroconversion rate for the measles virus by the measles component of KM-248 (n = 172) was shown to be non-inferior to that of the control measles vaccine (n = 85). No serious adverse reactions, such as aseptic meningitis or anaphylaxis, were observed. Fever is one of the most common adverse reactions associated with vaccination and was observed in approximately half of the participants. KM-248 administered to healthy Japanese children aged between 12 and 90 months demonstrated a comparable safety and efficacy profile to the control vaccine.

Hand, foot, and mouth disease (HFMD) due to Coxsackievirus A6 (CV-A6) has demonstrated an increasing trend in China. Our study aimed to explore the risk factors of HFMD cases infected with CV-A6 among children under 6 years of age in Tianjin, China. The non-matching case-control study included cases which were HFMD patients infected with CV-A6 while controls were HFMD patients infected with other enteroviruses. Multivariate logistic regression analysis was used to explore the risk factors of HFMD cases infected with CV-A6. A total of 1,264 eligible cases were included in our study, including 589 cases and 675 controls. Our study suggests that CV-A6 infected HFMD patients were more likely to present with fever and rash on limbs, and home-care children and children having a history of contacting HFMD patient had a high risk of infection with CV-A6, while toy sterilization regularly at home and parents’ hand-washing habits after toilet use were protective factors for children against CV-A6 infection.

During the 2017 outbreak of severe dengue in Sri Lanka, dengue virus (DENV) serotypes 2, 3, and 4 were found to be co-circulating. Our previous study of 295 patients from the National Hospital Kandy in Sri Lanka between March 2017 and January 2018 determined that the dominant infecting serotype was DENV-2. In this study, we aimed to characterize the DENV-3 strains from non-severe and severe dengue patients from our previous study population. Patients’ clinical records and previous laboratory tests, including dengue-specific nonstructural protein 1 antigen rapid test and IgM-capture and IgG enzyme-linked immunosorbent assays, were analyzed together with the present results of real-time reverse transcription polymerase chain reaction and next-generation sequencing of DENV-3. Complete genome analysis determined that DENV-3 isolates belonged to 2 different clades of genotype I and were genetically close to strains from Indonesia, China, Singapore, Malaysia, and Australia. There were 16 amino acid changes among DENV-3 isolates, and a greater number of changes were found in nonstructural proteins than in structural proteins. The emergence of DENV-3 genotype I was noted for the first time in Sri Lanka. Continuous monitoring of this newly emerged genotype and other DENV serotypes and genotypes is needed to determine their effects on future outbreaks and understand the molecular epidemiology of dengue.

To improve our current understanding of normal flora in children, we investigated bacterial isolates from the pharynx and nasopharynx of 173 and 233 healthy children, respectively. The bacterial isolation rates were compared among three age groups: infants (<1 year), toddlers (1–5 years), and school-aged children (6–15 years). Gram-positive cocci were the predominant bacteria in the pharynx (Streptococcus mitis/oralis, 87.3%; Streptococcus salivarius, 54.3%; Rothia mucilaginosa, 41.6%; Staphylococcus aureus, 39.3%). Among infants, S. salivarius and Neisseria subflava, which are related to the development of teeth, were significantly lower than in the other age groups (P <0.0001, S. salivarius; P <0.01, N. subflava). With the exception of Corynebacterium pseudodiphtheriticum (44.2%, gram-positive rods), gram-negative rods largely predominated the nasopharynx (Moraxella catarrhalis, 32.1%; Moraxella nonliquefaciens, 28.3%). Among toddlers, M. catarrhalis and Streptococcus pneumoniae, which are the most common pathogens in acute otitis media, were significantly higher than in the infant group (P <0.05). Among the bacterial species implicated in pediatric respiratory infections, Streptococcus pyogenes was isolated in 3.5% of the pharyngeal samples. S. pneumoniae and Haemophilus influenzae were isolated in 22.3% and 17.2% of the nasopharyngeal samples, respectively. In conclusion, the normal flora of the respiratory tract differs not only by the sampling site but also by the age group.

We aimed to determine the predictors of intensive care unit (ICU) admission or death in patients with coronavirus disease 2019 (COVID-19) pneumonia. This retrospective, single-center study included patients aged ≥18 years who were diagnosed with COVID-19 pneumonia (laboratory and radiologically confirmed) between March 9 and April 8, 2020. The composite endpoint was ICU admission or in-hospital mortality. Univariate and multivariate logistic regression analyses were performed to evaluate the factors associated with the composite endpoint. A total of 336 patients with COVID-19 pneumonia were evaluated. The median age was 54 years (interquartile range: 21), and 187 (55.7%) were men. Fifty-one (15.2%) patients were admitted to the ICU. In-hospital mortality occurred in 33 patients (9.8%). In the univariate analysis, 17 parameters were associated with the composite endpoint, and procalcitonin had the highest odds ratio (odds ratio [OR] = 36.568, confidence interval [CI] = 5.145–259.915). Our results revealed that body temperature (OR = 1.489, CI = 1.023–2.167, P = 0.037), peripheral capillary oxygen saturation (SpO2) (OR = 0.835, CI = 0.773–0.901, P < 0.001), and consolidation (> 25%) on chest computed tomography (OR = 3.170, CI = 1.218–8.252, P = 0.018) at admission were independent predictors. As a result, increased body temperature, decreased SpO2, a high level of procalcitonin, and degree of consolidation on chest computed tomography may predict a poor prognosis and have utility in the management of patients.

Soon after the 2019 outbreak of coronavirus disease 2019 in Wuhan, China, a protocol for real-time RT-PCR assay detection of severe acute respiratory syndrome coronavirus (SARS-CoV-2) was established by the National Institute of Infectious Diseases (NIID) in Japan. The protocol used Charité’s nucleocapsid (Sarbeco-N) and NIID nucleocapsid (NIID-N2) assays. During the following months, SARS-CoV-2 spread and caused a global pandemic, and various SARS-CoV-2 sequences were registered in public databases, such as the Global Initiative on Sharing All Influenza Data (GISAID). In this study, we evaluated the S2 assay (NIID-S2) that was newly developed to replace the Sarbeco-N assay and the performance of the NIID-N2 and NIID-S2 assays, referring to mismatches in the primer/probe targeted region. We found that the analytical sensitivity and specificity of the NIID-S2 set were comparable to those of the NIID-N2 assay, and the detection rate for clinical specimens was identical to that of the NIID-N2 assay. Furthermore, among the available sequences (approximately 192,000), the NIID-N2 and NIID-S2 sets had 2.6% and 1.2% mismatched sequences, respectively, although most of these mismatches did not affect the amplification efficiency, except the 3′ end of the NIID-N2 forward primer. These findings indicate that the previously developed NIID-N2 assay is suitable for the detection of SARS-CoV-2 with support from the newly developed NIID-S2 set.

In Japan, several rubella outbreaks in adults have erupted due to insufficient immunity against rubella virus (RUBV). Although selective immunization is being promoted along with routine rubella vaccination as its eradication strategy, serosurveillance against RUBV needs to be implemented in the generations corresponding to the vaccination transition period. In this study, a survey of anti-rubella immunoglobulin G (IgG) antibody titers was conducted among young adults involved in the transitional periods of the routine rubella vaccination program. Specifically, serosurveillance was performed in 370 healthy young adults aged 18–20 years, wherein their serum samples were analyzed using an enzyme immunoassay to determine rubella-specific IgG antibody titers. Although multiple regression analysis revealed significant differences only in medical history, more than 90% of participants exhibited seropositivity, excluding those who received a single-dose vaccine alone. Based on elapsed periods after the last vaccination, rubella-specific IgG antibody titers in less than a 6-year period were higher than those in more than a 10-year period. Although almost all study participants in the transitional period had seropositivity, the results may indicate that this persistence is related to past rubella outbreaks.

The pneumococcal conjugate vaccines successfully decreased the incidence of invasive pneumococcal diseases and pneumococcal antibiotic resistance. However, they also led to serotype replacements. According to a report by the National Institute of Infectious Diseases (NIID) in 2017, 96% of pneumococcal isolates obtained from children with IPD aged < 5 years were non-PCV13 serotypes. Here, we report the case of a Japanese immunocompetent and vaccinated child who developed refractory meningitis caused by Streptococcus pneumoniae nonvaccine serotype 10A. PCR revealed genotypic penicillin-resistant Streptococcus pneumoniae (gPRSP) with triple mutations (pbp1a + 2b + 2x). Multilocus sequence typing identified the strain as a sequence type (ST) 11189. The ST11189 strain has not been reported in Japan, but it has recently been reported as a cause of invasive infections in Korea. The clinical course was complicated by the development of brain and subdural abscesses that necessitated prolonged antibiotic treatment and multiple burr hole drainages. Unfortunately, the neurological sequelae persisted. Continued molecular surveillance is needed for monitoring emerging virulent clinical strains.

Despite the increase in COVID-19 cases globally, the number of cases in Japan has been relatively low, and an explosive surge in the prevalence has not occurred. In March 2020, the Ministry of Health, Labour and Welfare (MHLW) in Japan recommended the original criteria for polymerase chain reaction (PCR) testing, although there was a lack of evidence for appropriate targets for COVID-19 testing. This study aimed to evaluate the COVID-19 positive ratio and pre-screening criteria in Tokyo immediately after the insurance-covered SARS-CoV-2 PCR testing became available in Japan. We subjected 277 individuals with mild symptoms in metropolitan Tokyo (positive: 9.0%) from March 9 to 29, 2020, to SARS-CoV-2 PCR testing. The results revealed that 25 (9.0%) of them were PCR-positive. The sensitivity and specificity of the MHLW criteria were 100% and 10.7%, respectively. When the criteria excluded nonspecific symptoms, fatigue, and dyspnea, the sensitivity slightly decreased to 92%, and the specificity increased to 22.2%. The specificity was highest when the fever criterion was ≥37.5°C for ≥4 days, and exposure/travel history, including age and underlying comorbidities, was considered. Our findings suggest that the MHLW criteria, including the symptoms and exposure/travel history, may be useful for COVID-19 pre-screening.

In Japan, several meningococcal disease outbreaks have recently been reported among adolescent dormitory residents of schools. However, little is known about meningococcal carriage dynamics in healthy individuals. The purpose of this study was to investigate the carriage rate over time and characteristics of Neisseria meningitidis strains among dormitory students. The survey was conducted twice between November 2018 and January 2019 for first- to third-year students (N = 376) in a medical school dormitory. The two surveys yielded carriage rates of 0.4% (one positive among 257 students) and 2.1% (two positives among 97 students, including 90 re-participants). No transmission or persistence of a specific strain was observed during the two months. A limited number of students had a history of potential risk behaviors for carriage, such as smoking (3.0% [6/202] aged ≥20 years and 5.2% [4/77] aged ≥20 years, respectively) and attending parties more than once a week (4.3% [11/257] and 2.1% [2/97], respectively). Two isolates were unencapsulated, consistent with asymptomatic participants.