Mitsuo Uchida

Clinical features of a new disease concept, IgG4-related thyroiditis

Objectives: Immunoglobulin (Ig)G4-related disease is a recently proposed systemic disorder that includes autoimmune pancreatitis (AIP), Mikulicz’s disease, and various other organ lesions. In the present retrospective study, we examined whether thyroid lesions should also be included in IgG4-related disease (Ig4-RD) under the new term IgG4-related thyroiditis. Method: We enrolled 114 patients with Ig4-RD, including 92 patients with AIP, 15 patients with Mikulicz’s disease, and seven patients with IgG4-related cholangitis, and analysed clinical findings, function, serum values of activity markers, computed tomography (CT) images, and histology of the thyroid gland. Results: Among the 22 patients (19%) in our cohort who were found to have hypothyroidism [thyroid stimulating hormone (TSH) > 4 mIU/L], 11 patients had clinical hypothyroidism [free thyroxine (FT4) < 1 ng/dL] and 11 patients had subclinical hypothyroidism (FT4 ≥ 1 ng/dL). Serum concentrations of IgG, IgG4, circulating immune complex (CIC), and β2-microglobulin (β2-MG) were significantly higher in the hypothyroidism group compared with the remaining 92 euthyroid patients, and serum C3 concentration was significantly lower. After prednisolone treatment, TSH values had decreased significantly (p = 0.005) in this group and FT4 values had increased significantly (p = 0.047). CT images showed that the thyroid glands of patients with clinical hypothyroidism had a significantly greater volume than those of the euthyroid and other groups. Pathological analysis of one resected thyroid gland disclosed a focused lesion with infiltration of lymphocytes and IgG4-bearing plasma cells and loss of thyroid follicles. Conclusions: Thyroid lesions associated with hypothyroidism can be considered as a new disease termed IgG4-related thyroiditis. Awareness of this condition should lead to appropriate corticosteroid treatment that may prevent progression to a fibrous state.

Swine-Origin Influenza A Outbreak 2009 at Shinshu University, Japan

BackgroundA worldwide outbreak of swine flu H1N1 pandemic influenza occurred in April 2009. To determine the mechanism underlying the spread of infection, we prospectively evaluated a survey implemented at a local university.MethodsBetween August 2009 and March 2010, we surveyed 3 groups of subjects: 2318 children in six schools attached to the Faculty of Education, 11424 university students, and 3344 staff members. Subjects with influenza-like symptoms who were diagnosed with swine flu at hospitals or clinics were defined as swine flu patients and asked to make a report using a standardized form.ResultsAfter the start of the pandemic, a total of 2002 patients (11.7%) were registered in the survey. These patients included 928 schoolchildren (40.0%), 1016 university students (8.9%), and 58 staff members (1.7%). The incidence in schoolchildren was significantly higher than in the other 2 groups (P < 0.0001) but there were no within group differences in incidence rate between males and females. During the period of the survey, three peaks of patient numbers were observed, in November 2009, December 2009, and January 2010. The first peak consisted mainly of schoolchildren, whereas the second and third peaks included many university students. Staff members did not contribute to peak formation. Among the university students, the most common suspected route of transmission was club activity. Interventions, such as closing classes, schools, and clubs, are likely to affect the epidemic curves.ConclusionSchoolchildren and university students are vulnerable to swine flu, suggesting that avoidance of close contact, especially among these young people, may be effective way in controlling future severe influenza pandemics, especially at educational institutions.

How the H1N1 influenza epidemic spread among university students in Japan: Experience from Shinshu University

BACKGROUND A worldwide outbreak of influenza A/H1N1 occurred in 2009. Little information is available regarding how the epidemic spread among young people, who composed the majority of individuals infected with this virus. We assessed the route of transmission of H1N1 among university students at Shinshu University, Japan. METHODS A total of 11,424 students were monitored between August 2009 and March 2010, and those who were diagnosed with confirmed, probable, or suspected H1N1 at a hospital or clinic were registered based on self-report to the university. Data including date of onset and suspected infection route were collected from the affected patients. RESULTS Of the 11,424 students, 1,016 (8.9%) were infected with H1N1. In most infected students, the suspected transmission route was associated with club activity, followed by close contact with friends and through lectures or laboratory work. After suspension of activity by clubs with more than 2 infected members, the number of infected individuals decreased. CONCLUSION H1N1 influenza spread in the university through specific routes, including club activity, close contact with friends, and lectures or laboratory work. During future outbreaks of influenza, interventions to reduce transmission through these routes may be effective infection control strategies in university students.

Effectiveness of vaccination and wearing masks on seasonal influenza in Matsumoto City, Japan, in the 2014/2015 season: An observational study among all elementary schoolchildren

Measures of seasonal influenza control are generally divided into two categories: pharmaceutical and non-pharmaceutical interventions. The effectiveness of these measures remains unclear, because of insufficient study sample size and/or differences in study settings. This observational epidemiological study involved all elementary schoolchildren in Matsumoto City, Japan, with seasonal influenza during the 2014/2015 season. Questionnaires, including experiences with influenza diagnosis and socio-demographic factors, were distributed to all 29 public elementary schools, involving 13,217 children, at the end of February 2015. Data were obtained from 10,524 children and analyzed with multivariate logistic regression analysis. The result showed that vaccination (odds ratio 0.866, 95% confidence interval 0.786–0.954) and wearing masks (0.859, 0.778–0.949) had significant protective association. Hand washing (1.447, 1.274–1.644) and gargling (1.319, 1.183–1.471), however, were not associated with protection. In the natural setting, hand washing and gargling showed a negative association, which may have been due to inappropriate infection control measures or aggregating infected and non-infected children to conduct those measures. These results may indicate a pathway for influenza transmission and explain why seasonal influenza control remains difficult in school settings. The overall effectiveness of vaccination and mask wearing was 9.9% and 8.6%, respectively. After dividing children into higher (grades 4–6) and lower (grade 1–3) grade groups, the effectiveness of vaccination became greater in the lower grade group, and the effectiveness of wearing masks became greater in the higher grade group. These results may provide valuable information about designing infection control measures that allocate resources among children.

Prospective epidemiological evaluation of seasonal influenza in all elementary schoolchildren in Matsumoto City, Japan, in 2014/2015.

Seasonal influenza is known to spread within and among educational organizations. Detailed understanding of the pattern of infection requires comprehensive prospective epidemiological studies, involving all schools within a community. This prospective survey evaluated 13,217 schoolchildren attending all of the 29 public elementary schools in Matsumoto City, Japan, in 2014/2015. Questionnaires were distributed to school nurses to obtain information about onset date and suspected route of transmission of influenza for all schoolchildren diagnosed with influenza virus at medical institutions. Responses were obtained for 2,548 infected schoolchildren, representing 96% of reported cases. Epidemic curves were plotted for each school by calculating the numbers of incident cases. Distance between schools was not associated with influenza spread over time. However, modeling showed that the occurrence of initial infection at each school and its spread over time could be fitted with a logistic curve. The transmission route for most children initially infected at each school was through a household member, whereas for most remaining schoolchildren it was through the school. These findings indicated that seasonal influenza was initially transmitted to schoolchildren by household members and then spread throughout the schools, with the initially infected child at each school fitting logistic curves over time.

Role of household factors in parental attitudes to pandemic influenza-related school closure in Japan: a cross-sectional study

BackgroundTo investigate how household background factors affect parental behavior during pandemic influenza-related school closures, we determined associations between such factors and three parental attitudes: “caring for the child”, “taking leave from work”, and “permitting out-of-home activities”.MethodsA hypothetical pandemic influenza situation was presented and a questionnaire survey among households of 2146 schoolchildren from 6 schools was conducted. Odds ratios of background factors were estimated using univariate and multivariate logistic regression models.ResultsResponses pertaining to 1510 children indicated that junior high school (OR = 0.11), both parents working (OR = 0.03), and family including grandparent(s) or other relatives (OR = 7.50) were factors associated with “caring for the child”, and elementary school (OR = 2.28), special education school (OR = 3.18), and both parents working (OR = 5.74) were associated with “taking leave from work”. Having an older sibling (OR = 0.74) and awareness of the technical term for school closure (OR = 0.73) were factors associated with “permitting out-of-home activities”.ConclusionNot only work status but also other household factors may be associated with parental behaviors during pandemic influenza-related school closures.

Individual background factors associated with vaccination for seasonal influenza in Japanese schoolchildren

There is little evidence about how individual background factors affect seasonal influenza vaccination of children. At the end of the 2014/2015 influenza season, a cross-sectional questionnaire survey of all elementary schoolchildren in 29 schools in Matsumoto City, Japan, was conducted to obtain information about vaccine uptake activity and individual background factors. Of the 10,524 subjects who responded, 5063 (48.1%) had been vaccinated. Grade in school, underlying disease, number of siblings, and diagnosis with and vaccination for influenza during the previous influenza season differed significantly in vaccinated and unvaccinated groups. Multivariate logistic regression showed that underlying disease and vaccination during the previous influenza season was associated with a higher rate of vaccination, whereas higher grade in school and having ≥3 siblings was associated with a lower rate of vaccination. The findings may be useful to promote a vaccination policy recommending financial support to households with many children or to encourage higher uptake of vaccination in higher grade children.

High vaccination coverage is associated with low epidemic level of seasonal influenza in elementary schools: an observational study in Matsumoto City, Japan

BackgroundInfluenza virus transmission may be prevented by infection control measures, including vaccination, wearing a mask, gargling with water, and hand washing. It is unclear, however, whether these measures affect influenza epidemics in school settings.MethodsA prospective epidemiological survey in all public elementary schools in Matsumoto City, Japan, during the 2014/2015 season evaluated the number of diagnosed patients in each school and calculated the reproduction number of schoolchildren. At the end of the prospective survey, a cross-sectional survey evaluated the implementation of infection control measures in these schools. Both results were combined and associations among infection control measures including vaccination, mask wearing, hand washing, water gargling, and epidemic level were evaluated.ResultsOf the 13,217 schoolchildren in 29 schools, 2548 were diagnosed with seasonal influenza. A significant negative association was observed between vaccination coverage and reproduction number at each school, but not between other infection control measures and the reproduction number. A regression curve with exponential function was most predictive. At 0% vaccination, the reproduction number was estimated to be 1.39.ConclusionThese findings provide evidence that high vaccination coverage was associated with reduced epidemic levels in schools and suggest the need for increased vaccination of schoolchildren.

Does change of residence affect pollinosis? A study of Japanese university students.

The effects of change of residence on pollinosis symptoms remain unclear. We investigated the effects of geographical change of residence on pollinosis symptoms among university freshmen. All freshmen (n = 2142) entering Shinshu University in 2011 completed self-administered questionnaires. Associations between history of pollinosis and environmental factors were assessed. Subjects were classified into three groups according to pollen count at previous residences (stationary, low pollen, and high pollen). Pollinosis both before and after relocation were compared among and within the groups. Of the 1558 subjects, 540 (34.7%) developed pollinosis before and 483 (31.0%) after entering university. The rates of pre- and post-university entrance pollinosis were 40.0 and 32.5% in the high pollen group (P < 0.001) but were similar in the other two groups. Pollinosis symptoms decreased among students that moved from high to low pollen areas, indicating that pollinosis was affected by geographic environmental factors.