Epidemiologic Trends and Distributions of Imported Infectious Diseases Among Travelers to Japan Before and During the COVID-19 Pandemic, 2016 to 2021: A Descriptive Study.

BACKGROUND: Little is known about the trends of imported infectious diseases among travelers to non-endemic countries during the novel coronavirus disease 2019 (COVID-19) pandemic. This article aimed to describe those among travelers to Japan. METHODS: This is a descriptive study based on national surveillance data. Imported infectious disease cases were defined as those with a reported overseas source of infection among 15 diseases pre-selected based on the probability and impact of importation. The number of notified cases from April 2016 to March 2021 were described by disease and time of diagnosis. The relative ratio and absolute difference in case counts-both by number and per arrival-were calculated by disease comparing those from the pandemic period (April 2020-March 2021) to the pre-pandemic period (April 2016-March 2020). RESULTS: A total of 3,524 imported infectious disease cases were diagnosed during the study period, including 3,439 cases before and 85 cases during the pandemic. The proportionate distribution of diseases changed but notification counts of all 15 diseases decreased during the pandemic. Accounting for arrivals, however, seven diseases showed a two-fold or greater increase, with a notable absolute increase per million arrivals for amebiasis (60.1; 95% confidence interval [CI], 41.5-78.7), malaria (21.7; 95% CI, 10.5-33.0), and typhoid fever (9.3; 95% CI, 1.9-16.8). CONCLUSION: The epidemiology of imported infectious diseases changed during the pandemic. While the number of imported infectious disease cases decreased, the number of cases per arrivals increased considerably both in relative and absolute terms for several diseases of public health and clinical importance.

Rapid response to a COVID-19 outbreak at a nightclub in Kagoshima prefecture, Japan, in the early phase of the COVID-19 pandemic, June and July 2020: A descriptive epidemiological study.

INTRODUCTION: During COVID-19 pandemic in Japan, nightclubs were identified as high-risk locations for COVID-19 outbreaks, but an outbreak investigation in this setting is challenging because of the anonymous and opportunistic nature of interactions. METHODS: The joint rapid response team collected epidemiological data, conducted descriptive epidemiology to determine the characteristics of cases associated with the nightclub, and implemented countermeasures. Polymerase chain reaction (PCR) tests were performed by the Local Institute of Public Health, Kagoshima University, and several commercial laboratories. RESULTS: Between June 15 and July 20, 2020, 121 individuals tested positive for SARS-CoV-2 (59 confirmed and 62 asymptomatic) of whom 8 were nightclub staff who had no travel history of outside Kagoshima, 66 were guests, and 47 were subsequent contacts. The median age was 32 years (interquartile range: 24-43 years). One individual showed severe symptoms but there were no fatal. The epidemic curve showed one peak on June 30 and July 1 with a limited number of cases subsequently. Of the 121 cases, 116 and 5 were in individuals living in and outside Kagoshima Prefecture, respectively. Haplotype network analysis showed 5 genome-wide single-nucleotide variants between the isolates before and during this outbreak. CONCLUSIONS: There is a possibility that unidentified guests from outside Kagoshima Prefecture could infect staff who could subsequently spread the virus to guests and other staff, who were mainly a younger population. The rapid outbreak response enabled onward transmission in the community to be minimized. This outbreak investigation could provide insights for effective responses to challenging situations in future pandemic.

National Surveillance of Pediatric Acute Hepatitis of Unknown Etiology, Japan, October 2021-December 2022.

Pediatric acute hepatitis of unknown etiology has been reported globally since April 2022. In Japan, 139 possible cases with onset dates after October 2021 were reported as of December 2022. Three patients required liver transplants, but none died. Rates of adenovirus positivity (11/125, 9%) were lower than those for other countries.

SARS-CoV-2 Infection in Wrestlers after International Tournaments, April 2021.

Epidemiologic and genomic investigation of SARS-CoV-2 infections in members of Japan's national wrestling team after participation in international tournaments in 2021 revealed multiple lineages of SARS-CoV-2 not reported in Japan. The attack rate among wrestlers was high. Results suggest possible transmission during matches. We recommend early case detection and response practices.

Epidemiology of Coronavirus Disease Outbreak among Crewmembers on Cruise Ship, Nagasaki City, Japan, April 2020.

In April 2020, a coronavirus disease (COVID-19) outbreak occurred on the cruise ship Costa Atlantica in Nagasaki, Japan. Our outbreak investigation included 623 multinational crewmembers onboard on April 20. Median age was 31 years; 84% were men. Each crewmember was isolated or quarantined in a single room inside the ship, and monitoring of health status was supported by a remote health monitoring system. Crewmembers with more severe illness were hospitalized. The investigation found that the outbreak started in late March and peaked in late April, resulting in 149 laboratory-confirmed and 107 probable cases of infection with severe acute respiratory syndrome coronavirus 2. Six case-patients were hospitalized for COVID-19 pneumonia, including 1 in severe condition and 2 who required oxygen administration, but no deaths occurred. Although the virus can spread rapidly on a cruise ship, we describe how prompt isolation and quarantine combined with a sensitive syndromic surveillance system can control a COVID-19 outbreak.

Increase in congenital syphilis cases and challenges in prevention in Japan, 2016-2017.

In Japan, the increase in congenital syphilis (CS) notifications has become a public health concern. We conducted a case series study to describe the characteristics of CS patients and their mothers. Of the 13 mothers who consented to participate, seven had regular prenatal care visits, including four who had tested negative at their first trimester syphilis screening. Only three mothers noted that their partners were tested, with all three partners being diagnosed with syphilis. Raising awareness for syphilis prevention during pregnancy, partner testing, and considering additional syphilis testing at the third trimester of pregnancy during times of increased syphilis prevalence is imperative.

Severe Fever with Thrombocytopenia Syndrome, Japan, 2013-2017.

We conducted an epidemiologic study of severe fever with thrombocytopenia syndrome (SFTS) in Japan during 2013-2017. Of 303 cases reported during that period, 133 (44%) were included in this study. The median time between onset of illness and diagnosis of SFTS shortened, from 11.5 to 3.0 days, but the case-fatality rate remained high, at 27%. In 64 patients (48%), a close contact with companion animals was reported within 2 weeks of disease onset. Of these 64 patients, 40 were surveyed further, and we confirmed that 3 had direct contact with body fluids of ill companion animals; 2 had direct contact with the saliva of an ill feral cat or pet dog. These patients reported no history of tick bite, suggesting that ill companion animals might be a source of SFTS virus transmission. Direct contact with the body fluids of ill companion animals should be avoided.

Severe Acute Respiratory Syndrome Coronavirus 2 Infection among Returnees to Japan from Wuhan, China, 2020.

In early 2020, Japan repatriated 566 nationals from China. Universal laboratory testing and 14-day monitoring of returnees detected 12 cases of severe acute respiratory syndrome coronavirus 2 infection; initial screening results were negative for 5. Common outcomes were remaining asymptomatic (n = 4) and pneumonia (n = 6). Overall, screening performed poorly.

Characteristics and Outcomes of Influenza-Associated Encephalopathy Cases Among Children and Adults in Japan, 2010-2015.

Background: Influenza-associated encephalopathy (IAE) can result in severe neurologic disease with high mortality. Most IAE cases are reported among children worldwide. Understanding of IAE among adults is limited. Methods: Data were collected on IAE cases reported through the National Epidemiological Surveillance of Infectious Diseases database in Japan from 2010 through 2015. IAE cases were stratified by age category and analyzed using descriptive statistics to assess differences in characteristics and outcomes. Results: Among 385 IAE cases, median age at diagnosis was 7 years (range, 0-90), and 283 (74%) were aged <18 years. Mean seasonal incidence of IAE cases among children and adults (aged ≥18 years) was 2.83 and 0.19 cases per 1000000 population, respectively. IAE incidence did not vary by predominant influenza A virus subtype. IAE frequency was highest in school-aged (5-12 years) children (38%), followed by children aged 2-4 years (21%) and adults aged 18-49 years (11%). The proportion of cases with seizures was more common in children. There were more cases with cerebrospinal fluid pleocytosis among adults than in children (P < .01), especially among those aged 18-49 (17%) and 50-64 (19%) years. Case fatality proportion was highest in those aged 40-64 (17%) and ≥65 (20%) years. Conclusions: We found differences in the clinical features of IAE between adults and children in Japan. Although IAE incidence was higher in children, mortality was higher in adults. Efforts are needed to prevent and improve survival of patients with IAE, especially in adults.

Sociodemographic characteristics and clinical description of congenital syphilis patients and their mothers in Japan: a qualitative study, 2016.

Background In Japan, congenital syphilis (CS) notifications have increased recently. However, little is known about the CS cases or the clinical and sociodemographic characteristics of the patients' mothers. METHODS: Twelve cases of CS were reported through national surveillance in the period March-December 2016, and the mothers of seven patients were included in this study. The patients' mothers and physicians completed a self-administered questionnaire, providing sociodemographic and clinical information of the patients and their mothers. In addition, we explored the awareness and knowledge of, attitudes towards and practices regarding CS occurrence through semistructured interviews with the mothers. RESULTS: Of the seven CS patients, three were asymptomatic, with a range of non-specific clinical manifestations in the rest. The mothers tended to be of young age, unmarried and to have a history of commercial sex work, other sexually transmissible infections (STIs) and no or irregular prenatal care visits during pregnancy. Of the four mothers who had had regular prenatal care visits, two had tested negative for syphilis at the first trimester antenatal screening. Themes emerged that indicated challenges in preventing CS, including a lack of guidance or guidelines for physicians to consider testing for syphilis after the first trimester, lack of physicians' awareness or experience of syphilis or CS and a lack of awareness or knowledge in pregnant women regarding STIs. CONCLUSIONS: Key characteristics of recent CS patients and their mothers in Japan were revealed, identifying previously reported factors as well as new challenges. A holistic approach, designed to address challenges at the level of the healthcare system, healthcare provider and the pregnant woman and her partner will be important in preventing CS.

Ebola hemorrhagic fever/Ebola virus disease - Marburg disease - Lassa fever.

Ebola virus disease, Marburg disease, and Lassa fever are viral hemorrhagic fevers with similar clinical manifestations. Given the recent expanding movement of people around the world, persons infected with any of these hemorrhagic fever viruses might develop symp- toms in Japan. Clinicians should be aware of the latest situation once viral hemorrhagic fever is reported from any country. Obtaining travel history is crucial in suspecting viral hemorrha- gic fever when an acute febrile patient visits a medical facility. Secure implementation of standard precautions would limit further nosocomial transmission even before diagnosis. In order to investigate promptly a suspected case, medical facilities and health authorities should collaborate closely and effectively to break the transmission chain as soon as possi- ble.

Epidemiological situation of Ebola virus disease in West Africa.

After Guinea reported an outbreak of Ebola virus disease (EVD) in March 2014, EVD spread to neighboring Sierra Leone and Liberia in West Africa. Since then, the EVD outbreak spread over a wide geographic area among these three countries, and became the largest EVD epidemic ever with unprecedented numbers of confirmed cases and fatalities. As of April 2015, one year past the start of the outbreak, transmission is still ongoing. And, while six other countries, including those outside of the African continent (the United Kingdom, Spain, and the United States), have reported EVD cases, the source of the infection all originated from Guinea, Sierra Leone, or Liberia. As for the pathogen, Ebola virus, the route of transmission and associated prevention measures are well known, and change in the virulence or transmissibility of the virus has not been confirmed. However, there are specific factors that likely contributed to the unprecedented magnitude of the current EVD outbreak. In addition to the limited and poor medical and public health infrastructure in the affected countries, implementing appropriate responses rapidly was challenging for these countries, whose medical community, the general public, and governments had never experienced EVD before.

How do field epidemiologists learn? A protocol for a qualitative inquiry into learning in field epidemiology training programmes.

INTRODUCTION: COVID-19 underscored the importance of field epidemiology training programmes (FETPs) as countries struggled with overwhelming demands. Experts are calling for more field epidemiologists with better training. Since 1951, FETPs have been building public health capacities across the globe, yet explorations of learning in these programmes are lacking. This qualitative study will (1) describe approaches to training field epidemiologists in FETP; (2) describe strategies for learning field epidemiology among FETP trainees and (3) explain the principles and practices aligning training approaches with learning strategies in FETP. METHODS AND ANALYSIS: The research design, implementation and interpretation are collaborative efforts with FETP trainers. Data collection will include interviews with FETP trainers and trainees and participant observations of FETP training and learning events in four FETP in the Western Pacific Region. Data analysis will occur in three phases: (1) we will use the constant comparison method of Charmaz's grounded theory during open coding to identify and prioritise categories and properties in the data; (2) during focused coding, we will use constant comparison and Polkinghorne's analysis of narratives, comparing stories of prioritised categories, to fill out properties of those categories and (3) we will use Polkinghorne's narrative analysis to construct narratives that reflect domains of interest, identifying correspondence among Carr and Kemmis's practices, understandings and situations to explain principles and processes of learning in FETP. ETHICS AND DISSEMINATION: We have obtained the required ethics approvals to conduct this research at The Australian National University (2021/771) and Taiwan's Ministry of Health and Welfare (112206). Data will not be available publicly, but anonymised findings will be shared with FETP for collaborative interpretation. Ultimately, findings and interpretations will appear in peer-reviewed journals and conferences.

[A case of lyme disease requiring over 1 year to diagnose at an infectious-disease clinic].

A 42-year-old woman presenting with years of fever and vague symptoms could not be satisfactorily diagnosed in physical examination or conventional workups. She was presumptively diagnosed with chronic fatigue syndrome and treated symptomatically. Fourteen months after the initial visit, she developed left facial palsy. Lyme disease serology was positive. Four weeks of oral amoxicillin ameliorated symptoms. Only 5 to 15 cases of Lyme disease are reported annually in Japan, mostly from the northeastern-most island of Hokkaido. It may occur anywhere in Japan, however; probably is underdiagnosed. Lyme disease may cause fevers of unknown origin. Astute clinical suspicion and appropriate workups are thus needed to diagnose this infection.

[Training programs for staff at local Infectious Disease Surveillance Centers: the needs and usefulness].

OBJECTIVES: The objective of this study was to assess the need for and usefulness of training programs for Local Infectious Disease Surveillance Center (LIDSC) staff. METHODS: A structured questionnaire survey was conducted to assess the needs and usefulness of training programs. The subjects of the survey were participants of a workshop held after an annual conference for the LIDSC staff. Data on demographic information, the necessity of training programs for LIDSC staff, the themes and contents of the training program, self-assessment of knowledge on epidemiology and statistics were covered by the questionnaire. RESULTS: A total of 55 local government officials responded to the questionnaire (response rate: 100%). Among these, 95% of participants believed that the training program for the LIDSC staff was necessary. Basic statistical analysis (85%), descriptive epidemiology (65%), outline of epidemiology (60%), interpretation of surveillance data (65%), background and objectives of national infectious disease surveillance in Japan (60%), methods of field epidemiology (60%), and methods of analysis data (51%) were selected by over half of the respondents as suitable themes for training programs. A total of 34 LIDSC staff answered the self-assessment question on knowledge of epidemiology. A majority of respondents selected "a little" or "none" for all questions about knowledge. Only a few respondents had received education in epidemiology. CONCLUSION: The results of this study indicate that LIDSC staff have basic demands for fundamental and specialized education to improve their work. Considering the current situation regarding the capacity of LIDSC staff, these training programs should be started immediately.

Baseline and seasonal trends of Bacillus cereus and Bacillus subtilis from clinical samples in Japan.

Background: Outbreaks of Bacillus cereus bloodstream infections (BSIs) are a concern in Japanese medical settings. Aim: This study determined baseline values for B. cereus detection in clinical samples that are useful as reference values for hospitals when assessing the need for intervention. Method: A retrospective analysis of B. cereus detection in the Japan Nosocomial Infections Surveillance data from 2008 to 2014 was performed; it included 950 individual hospitals across the country. Findings: Bacillus spp. were detected in 0.54% of the clinical specimens submitted for bacteriological testing. Specimens positive for Bacillus spp. were mainly blood (24.6%), stool (26.5%), and respiratory specimens (23.3%). Identification of Bacillus spp. at the species level (i.e., B. cereus or B. subtilis) was reported in 55.3%, 14.7%, and 15.4% of cases, of which 88.9%, 48.3%, and 33.1% were B. cereus in blood, stool, and respiratory specimens, respectively. Of the 4105 hospital-years, 75.7% had blood specimens with Bacillus spp., with a median of 0.85 blood specimens/100 beds annually (interquartile range, 0.17-2.10). The B. cereus detection showed significant summer seasonality, regardless of specimen type or geographic distribution. The B. subtilis detection did not show seasonality, and its detection remained constant throughout the year. The seasonality of Bacillus spp. reflects the high proportion of B. cereus. Conclusions: The increased detection rate of Bacillus spp. during summer should be interpreted as a risk factor for B. cereus BSIs. A post-summer decrease in Bacillus spp. should not be interpreted as an effect of interventions.

Association of a promotional campaign for local dining facilities with the occurrence of COVID-19 in Asahikawa City, Japan, in November 2021.

Objectives: As social restrictions of COVID-19 are being eased worldwide, preventing SARS-CoV-2 transmission among staff members and customers in dining facilities is essential to continuously running business because restaurants and bars are high-risk locations for COVID-19 outbreaks. In 2021, COVID-19 outbreaks occurred at restaurants or bars in Asahikawa city, Japan two weeks after the launch of a promotional campaign for local dining facilities. We investigated this event to assess the association between the promotional campaign and the occurrence of SARS-CoV-2 infection. Study design: Cohort study. Methods: We assessed the association between the occurrence of COVID-19 cases in the restaurants and bars and their participation in the campaign by calculating risk ratio and 95% confidence interval. Results: Cases were identified among workers or customers in 4.0% (4/101) of the participating restaurants or bars and in 1.2% (39/3257) of the non-participating restaurants or bars. The risk ratio was 3.3 (95% confidence interval 1.2-9.0). Conclusion: The association between the occurrence of SARS-CoV-2 infection in the restaurants or bars and participation in the campaign is undeniable. Promotional campaigns to vitalize dining facilities should be accompanied by enhanced infection prevention measures, especially ventilation.

Transmission of COVID-19 in Nightlife, Household, and Health Care Settings in Tokyo, Japan, in 2020.

Importance: There have been few studies on the heterogeneous interconnection of COVID-19 outbreaks occurring in different social settings using robust, surveillance epidemiological data. Objectives: To describe the characteristics of COVID-19 transmission within different social settings and to evaluate settings associated with onward transmission to other settings. Design, Setting, and Participants: This is a case series study of laboratory-confirmed COVID-19 cases in Tokyo between January 23 and December 5, 2020, when vaccination was not yet implemented. Using epidemiological investigation data collected by public health centers, epidemiological links were identified and classified into 7 transmission settings: imported, nightlife, dining, workplace, household, health care, and other. Main Outcomes and Measures: The number of cases per setting and the likelihood of generating onward transmissions were compared between different transmission settings. Results: Of the 44 054 confirmed COVID-19 cases in this study, 25 241 (57.3%) were among male patients, and the median (IQR) age of patients was 36 (26-52) years. Transmission settings were identified in 13 122 cases, including 6768 household, 2733 health care, and 1174 nightlife cases. More than 6600 transmission settings were detected, and nightlife (72 of 380 [18.9%]; P < .001) and health care (119 [36.2%]; P < .001) settings were more likely to involve 5 or more cases than dining, workplace, household, and other settings. Nightlife cases appeared in the earlier phase of the epidemic, while household and health care cases appeared later. After adjustment for transmission setting, sex, age group, presence of symptoms, and wave, household and health care cases were less likely to generate onward transmission compared with nightlife cases (household: adjusted odds ratio, 0.03; 95% CI, 0.02-0.05; health care: adjusted odds ratio, 0.57; 95% CI, 0.41-0.79). Household settings were associated with intergenerational transmission, while nonhousehold settings mainly comprised transmission between the same age group. Among 30 932 cases without identified transmission settings, cases with a history of visiting nightlife establishments were more likely to generate onward transmission to nonhousehold settings (adjusted odds ratio, 5.30 [95% CI, 4.64-6.05]; P < .001) than those without such history. Conclusions and Relevance: In this case series study, COVID-19 cases identified in nightlife settings were associated with a higher likelihood of spreading COVID-19 than household and health care cases. Surveillance and interventions targeting nightlife settings should be prioritized to disrupt COVID-19 transmission, especially in the early stage of an epidemic.

Specific COVID-19 risk behaviors and the preventive effect of personal protective equipment among healthcare workers in Japan.

As coronavirus disease 2019 (COVID-19) outbreaks in healthcare facilities are a serious public health concern, we performed a case-control study to investigate the risk of COVID-19 infection in healthcare workers. We collected data on participants' sociodemographic characteristics, contact behaviors, installation status of personal protective equipment, and polymerase chain reaction testing results. We also collected whole blood and assessed seropositivity using the electrochemiluminescence immunoassay and microneutralization assay. In total, 161 (8.5%) of 1,899 participants were seropositive between August 3 and November 13, 2020. Physical contact (adjusted odds ratio 2.4, 95% confidence interval 1.1-5.6) and aerosol-generating procedures (1.9, 1.1-3.2) were associated with seropositivity. Using goggles (0.2, 0.1-0.5) and N95 masks (0.3, 0.1-0.8) had a preventive effect. Seroprevalence was higher in the outbreak ward (18.6%) than in the COVID-19 dedicated ward (1.4%). Results showed certain specific risk behaviors of COVID-19; proper infection prevention practices reduced these risks.

Rapid response to a coronavirus disease 2019 (COVID-19) outbreak in a psychiatry hospital-Kanazawa City, Japan, March to April 2020.

A coronavirus disease 2019 (COVID-19) outbreak in a psychiatry hospital revealed specific challenges in its response such as difficulty in isolation, transfer, and identification of close contacts, suboptimal infection control practices, and shortage of personal protective equipment, which were overcome by support from the public health center and a neighboring university hospital.