Leptospirosis is a globally important zoonotic disease and an important public health problem in developing countries. Early diagnosis is essential because antibiotic treatment is most effective when initiated early in the course of the disease. Culture and the microscopic agglutination test are gold standard methods for leptospirosis diagnosis; however, they are not useful for early diagnosis. Current whole cell-based rapid serological tests have low sensitivity for early phase leptospirosis and may have low specificity in highly endemic areas. PCR is demonstrably useful for early diagnosis, but it is unavailable in most developing countries. Thus, diagnostic methods that not only have higher sensitivity and accuracy for early phase leptospirosis but are also widely applicable in developing countries remain to be developed. The availability of genome sequences and genetic tools of Leptospira spp. will accelerate our understanding of Leptospira pathogenesis and provide insights into the development of more efficient and accurate diagnostic tests for acute-phase leptospirosis.

Between 9 May and 4 June 2009, a total of 401 laboratory-confirmed cases of influenza A(H1N1)v virus were reported in Japan, from 16 of the 47 Japanese prefectures. The two areas most affected were Osaka prefecture and Kobe city where outbreaks in high schools occurred leading to school closures. To date all cases have had symptoms consistent with seasonal influenza and no severe or fatal cases have been reported.

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Background Coronavirus disease (COVID‐19), caused by severe acute respiratory syndrome coronavirus (SARS‐CoV‐2), has rapidly spread globally. Potentially infected individuals travel on commercial aircraft. Thus, this study aimed to investigate and test the association between the use of face masks, physical distance, and COVID‐19 among passengers and flight attendants exposed to a COVID‐19 passenger in a domestic flight. Methods This observational study investigated passengers and flight attendants exposed to COVID‐19 on March 23, 2020, on board a flight to Naha City, Japan. Secondary attack rates were calculated. Whole‐genome sequencing of SARS‐CoV‐2 was used to identify the infectious linkage between confirmed cases in this clustering. The association between confirmed COVID‐19 and proximity of passengers' seats to the index case and/or the use of face masks was estimated using logistic regression. Results Fourteen confirmed and six probable cases were identified among passengers and flight attendants. The secondary attack rate was 9.7%. Twelve of 14 SARS‐CoV‐2 genome sequences in confirmed cases were identical to that of the index case or showed only one nucleotide mutation. Risk factors for infection included not using a face mask (adjusted odds ratio [aOR]: 7.29, 95% confidence interval [95% CI]: 1.86‐28.6), partial face mask use (aOR: 3.0, 95% CI: 0.83‐10.8), and being seated within two rows from the index patient (aOR: 7.47, 95% CI: 2.06‐27.2). Conclusion SARS‐CoV‐2 was transmitted on the airplane. Nonuse of face masks was identified as an independent risk factor for contracting COVID‐19 on the airplane.

We assessed the effect of seasonal trivalent inactivated influenza vaccination (TIV) on pandemic influenza 2009 (pH1N1)-related illness from April to June 2009 among 2849 students (aged 12-18 years). TIV was associated with an increase in the frequency of pH1N1-related illness among subjects (adjusted odds ratio, 1.47; 95% confidence interval, 1.14-1.89). TIV during the 2008-2009 season increased the risk of pH1N1-related illness from April to June 2009.

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Leptospirosis is considered underdiagnosed because of its nonspecific presentation and lack of proper understanding of its epidemiology. Early diagnosis and treatment are crucial. However, few data are available on confirmed leptospirosis cases in children in industrialized countries. We therefore aimed to describe epidemiologic and clinical characteristics of laboratory-confirmed childhood leptospirosis in Okinawa, Japan. We reviewed the national surveillance data of pediatric leptospirosis in Okinawa, Japan from January 2003 through December 2015. The database included all of laboratory-confirmed leptospirosis diagnosed at the only central laboratory for leptospirosis in the region. There were 44 children (0–20 years of age) with laboratory-confirmed leptospirosis. Of these, 90% were male, 91% were 10–20 years of age, and 96% of cases occurred in August and September. The number of laboratory-confirmed patients ranged from 0 to 11 per year (mean: 3.3 per year), and the estimated annual rate was 1.0 per 100,000 pediatric populations. In all cases, the presumed infection route was recreational exposure to river water. Commonly observed manifestations include fever (95%), myalgia (52%), and conjunctival suffusion (52%). Childhood leptospirosis in Okinawa, Japan occurred predominantly in teenage boys after freshwater exposure in summer, and most patients had characteristic conjunctival suffusion. Cohort studies would be helpful to better understand more detailed clinical manifestations in association with prognosis.

SUMMARY: Raw fish consumption is increasing worldwide. Since around the year 2000, western regions of Japan have reported a foodborne disease of unknown cause that occurred after the consumption of flounder. In October 2010, a particularly large outbreak was reported in these regions among individuals who consumed flounder fish that had been raised in aquaculture systems. The median incubation period was 5 h (range, 4-19 h), and the most frequently reported symptom was diarrhea (80z). The risk estimate of the consumption of flounder was significantly higher than that of the development of symptoms (odds ratio ＝ 9.50; 95z confidence interval, 1.59-/). According to a trace-back investigation, all of the flounder responsible for the outbreak were raised in aquaculture systems. Microscopic examination revealed that the median amount of Kudoa septempunctata present in the muscle of flounder fish from the aquaculture farm was 4.5 × 10 3 spores/g (range, 1.0 × 10 3 -9.6 × 10 6 spores/ g). The number of K. septempunctata spores required for the development of illness, as estimated using the Monte Carlo simulation, was 7.2 × 10 7 spores/g; therefore, thus this might be the minimum ingestion threshold for the development of gastrointestinal symptoms. As a public health measure, the current study results should be referred to for the prevention of the gastrointestinal symptoms related to the consumption of flounder; the national public health authority has disseminated these results. We concluded that K. septempunctata-contaminated flounder fish were associated with the gastrointestinal symptoms of this recent outbreak.