[An autochthonous outbreak of dengue type 1 in Tokyo, Japan 2014].

OBJECTIVES: An outbreak of autochthonous dengue fever was reported in August 2014, with cases suspected mainly from Yoyogi Park in Tokyo. This is the first epidemic of dengue fever in Japan since 1945. METHODS: From August to October 2014, the following measures were taken to control the outbreak: 1) risk communication and information sharing; 2) active case finding; 3) vector surveillance in affected sites; and 4) laboratory testing. We also reviewed the surveillance data as reported to the National Epidemiological Surveillance of Infectious Diseases during the 44 epidemiological weeks. results: An official dengue fever call center was set up temporarily for the general public and 3,005 calls were received. The Tokyo Metropolitan Government issued 39 press releases regarding patients and nine related to dengue virus (DENV) detection and vector control activities for the media. Confirmed autochthonous dengue fever cases were reported between the 35th and 44th epidemiological weeks. Out of 160 cases of outbreak, 108 (67.5%) confirmed cases were reported in Tokyo. The estimated illness onset dates were between August 9 and October 7, and estimated dates of infections were between August 3 and October 3, 2014. The data suggest that the infective mosquitoes had already been present in Yoyogi Park at the end of July 2014. During the weekly vector surveillance at Yoyogi Park, a total of 1,152 adult mosquitoes, of which 856 (73.3%) were Aedes mosquitoes, were collected over 11 weeks by a light trap with dry ice. DENV was detected from adult Aedes mosquito samples collected on the 2nd, 9th, and 16th of September, 2014. Serum samples from 240 suspected cases were examined at the Tokyo Metropolitan Institute of Public Health, and 78 were positive for the DENV NS1 antigen, DENV-specific IgM antibody, or DENV nucleic acid with reverse transcriptase polymerase chain reaction (RT-PCR) (NS1: 66 cases; IgM: 50 cases; PCR: 57 cases). Genetic analysis of DENV-positive serum and mosquito samples found all to be categorized as DENV-serotype 1 (gene type I). Phylogenetic analysis of the envelope protein genome sequence from patients and mosquitoes in Tokyo revealed more than 99% similarity with each other and with the strain from the first outbreak-associated patient in Saitama. CONCLUSION: Measures important for control of infectious disease epidemic were learned during this recent indigenous dengue outbreak in Tokyo. It also highlighted the importance of preparedness for epidemics of indigenous or imported infectious diseases, especially in light of the fact that Tokyo is in preparation for the Olympic and Paralympic Games in 2020.

Enhanced Surveillance for the Sports Festival in Tokyo 2013: Preparation for the Tokyo 2020 Olympic and Paralympic Games.

Enhanced surveillance was conducted during the Sports Festival in Tokyo 2013 (September 28-October 14, 2013) for early detection of outbreaks of infectious diseases and other health emergencies. Through this enhanced surveillance, 15 cases were found that required additional gathering of information outside the routine process of creating/evaluating the Daily Report. However, none of these was assessed as critical. Through the enhanced surveillance, we structured a framework that allows for earlier response when detecting aberrations. It includes the role of the Tokyo Metropolitan Government in communications and contacts with relevant parties such as public health centers, as well as in monitoring of surveillance data. However, some issues need to be further considered toward the Tokyo 2020 Olympic and Paralympic Games, such as establishing the criteria for additional response steps, increasing the number of participating bodies in syndromic surveillance, and strengthening of cooperation with related departments, including those for crisis management assuming potential biological/chemical terrorism.

[A case of multiple-drug-resistant pulmonary tuberculosis in a hemodialysis hospital].

A 42-year-old male with chronic renal failure was diagnosed as multiple-drug-resistant pulmonary tuberculosis, 9 months after the onset of hemodialysis. During the period before the diagnosis of tuberculosis, he visited regularly the hemodialysis hospital, accordingly many patients with hemodialysis and the hospital staffs had close and long contact with the patient. Our health center planned and conducted contact examinations among them, with QFT-TB test and chest X-ray. Petients with hemodialysis are regarded as immunocompromised hosts, one of the high risk groups for infections. The result of QFT-TB test of patients were negative, however, we have to cosider the possibility of false-negative. So we followed up by monthly chest X-ray examination all hemodialysis patients for 2 years, and finally, it was found that secondary infection of multiple-drug-resistant tuberculosis among immunocompromised hosts did not occur.

[Estimation of the prevalence of tuberculosis infection in the 1950s in Tokyo].

PURPOSE: We estimated the prevalence of tuberculosis infection in the 1950s in the urban area of Tokyo using results of the tuberculin skin test (TST) in infants and children. SUBJECT AND METHODS: We analyzed prevalence of tuberculosis using the results of the TST in 728 children (5 m.o.-24 m.o.) without BCG vaccination in 1954 in Koto Ward, Tokyo. RESULTS: Assuming that the sensitivity and specificity of the TST were 95% and 98%, respectively, the prevalence of TB was estimated to be 2% (95% C.I., 0.4-4.3%) among 448 infants under 12 m.o. (mean age 0.69 y.o.), and 16% (95% C.I., 11.9-21.5%) among 280 children aged 12 m.o.-24 m.o. (mean age 1.44 y.o.). CONCLUSION: Being different from the current situation of tuberculosis, the risk of infection among infants was high in 1950s in Japan, therefore, it was considered that the prevalence of tuberculosis infection rose rapidly among infants in their early period after birth. Also, the risk of infection in urban areas was higher comparing with the average national rate at that time.

[Geospatial analysis of tuberculosis in Tokyo].

PURPOSE: To assess geographic variations in the incidence of tuberculosis in Tokyo. METHODS: Using information on tuberculosis incidence, 2000 to 2002, from the annual notification report, patients were categorized into 8 groups by sex and age. We then calculated the Standardized Incidence Ratio (SIR) for each of the 23 wards in Tokyo. The SIR map was described by spatial interpolation and evaluated by cross validation. Spatial scan statistics were used to detect the significance of high-risk areas across the region. We compare this with the proportional distribution of those receiving public assistance and according to the SIR. RESULTS: The geographic variations of SIR did not show a uniform pattern for each group. Spatial scan statistics clearly identified locations, that were significantly high for male groups over 20 years old. Groups under 20 years old and all female groups did not produce high incidence cluster, which are likely to demonstrate spatial features of the proportion of those receiving public assistance. CONCLUSIONS: The geographic distribution of the proportion of those receiving public assistance should impact upon the geographic distribution of the high incidence clusters. However, considering the results of the young age group and each female group, we suggest that recent infection risk among local habitants was almost uniform, with a slightly higher tendency in urban locations of Tokyo.

[Correlaton of mortality for lower urinary tract cancer and medical resource factor].

PURPOSE: To compare mortality among different populations, the standardized mortality ratio (SMR) is usually used. This study is investigated the relationships between health care resources and mortality for lower urinary tract cancer. MATERIALS AND METHODS: Data for medical resource factors were obtained from annual reports published by the Ministry of Health, Labor and Welfare, Japan. A Bayesian regression model was used to examine the relationships between SMR and these factors. The SMRs for prostate cancer and bladder cancer were calculated for the period from 2000 to 2002 and for 1990. RESULTS: When the number of urological hospitals increased to 1 per 100,000 person in a region, the influence of the SMR for prostate cancer was - 3.0 - 0.5%, the male bladder cancer SMR was - 0.2 - 1.8% and the female bladder cancer SMR was - 2.6 - 0.8%. These findings were not significant. CONCLUSION: The study shows that an appropriate distribution of urology resources is one of the factors contributing to a reduction in the mortality for urological cancer in a region. However, further increase of urological hospitals in a region exerts a limited beneficial influence on reducing the mortality.

[The transmission of tuberculosis in a cram school].

PURPOSE: The specificity of the tuberculin skin test (TST) is influenced by the previous BCG vaccination during childhood in Japan. The QuantiFERON (QFT) is expected to detect latent infection among tuberculosis contacts, however, its use is still limited. We report a case of TB outbreak that caused by a private lesson teacher. His sputum was found to be acidfast bacillus-positive (Gaffky 4) by smears examination. We evaluated the risk factors of TB infection using TST among contacts. MATERIAL AND METHOD: A total of 184 persons were examined by a TST. These results were used to estimate the rate of TB infection by a mixture model. Logit analysis was also performed to estimate the number of infected person by using the relation between the positive rate of QFT and the size of erythema using a past report. We applied the Wells-Riley mathematical model of airborne transmission to calculate the risk of infection. RESULT: As compared with persons who had less contact with the index TB case, the estimated rate of TB infection was higher among persons who had close contact during the month before the index case started medical treatment (5% vs 23%). According to the model, the case added 1.1-4.0 quanta per hour (qph) to the room during a month before starting the treatment. CONCLUSION: These results suggest the importance of an early diagnosis of the index case to prevent TB infection.

Association of heart rate with coronary risk factors and increased white blood cell counts in healthy Japanese people.

Elevated resting heart rate (HR) is associated with hypertension in addition to or similar to increased incidence of cardiovascular morbidity and mortality. Subjects with high HR exhibit the characteristic features of insulin resistance syndrome. Sympathetic overactivity underlies this clinical condition. However, the true mechanism of high HR is unclear. We examined the relation between resting HR and age, gender, traditional coronary risk factors, and white blood cell (WBC) count in urban Japanese. The study population comprised 2,736 people aged 40, 50, and 60 years old. Multiple regression analysis of the total population showed that gender (p < 0.001), systolic and diastolic blood pressure (SBP, DBP; p < 0.001), serum triglycerides (TG; p < 0.001), fasting plasma glucose (FPG; p < 0.001) and WBC count (p < 0.001) had significant correlations with HR in the total population. Exercise was negatively correlated with HR (p < 0.001). In the age-adjusted profiles, gender (p < 0.001), SBP (p < 0.001), FPG (p < 0.001, p < 0.01 at age 40 years) and WBC count (p < 0.001) showed a significant correlation with HR among all three age groups. A negative association between HDL cholesterol (HDLc) and HR was seen at age 60 years (p < 0.01). A negative correlation between exercise and HR was seen at age 40 years (p < 0.001) and age 50 years (p < 0.01). It is suggested that the WBC count is one of the important determinants of resting HR regardless of age. Further studies are necessary to clarify the link between HR, coronary risk factors, and chronic infections.