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We propose a mathematical model of the transmission dynamics of colonization by commensal bacteria within a human community subject to varying levels of antibiotic use designed to control morbidity induced by pathogenic strains of the normally commensal organisms. Colonization is assumed not to induce morbidity in the majority of cases, and antibiotic use is assumed to be related to the arrival and growth of pathogenic strains that give rise to infections including clinical symptoms of disease. In the absence of antibiotic resistance, the model shows how the pattern of antibiotic prescription and use can eliminate the non-pathogenic commensal strains from the host community if the fraction of people taking antibiotics with a defined efficacy exceeds some critical level. The model is extended to take account of the evolution of antibiotic resistance in the commensal population. We assume resistance may be either plasmid-mediated or conferred by selection of low-level pre-existing mutants, and that resistant organisms may experience reduced reproductive fitness. Invasion of the host community by drug-resistant commensals is possible if certain antibiotic prescribing patterns pertain. We calculate these conditions in terms of the transmission parameter of the organism and the level of antibiotic prescription and use. The model is employed to address the issues of how best to use antibiotics in populations harbouring resistant organisms, and when resistant bacteria will out-compete sensitive strains.

BackgroundSchool closure is considered as an effective measure to prevent pandemic influenza. Although Japan has implemented many class, grade, and whole school closures during the early stage of the pandemic 2009, the effectiveness of such a school closure has not been analysed appropriately. In addition, analysis based on evidence or data from a large population has yet to be performed. We evaluated the preventive effect of school closure against the pandemic (H1N1) 2009 and examined efficient strategies of reactive school closure.Materials and MethodsData included daily reports of reactive school closures and the number of infected students in the pandemic in Oita City, Japan. We used a regression model that incorporated a time delay to analyse the daily data of school closure based on a time continuous susceptible-exposed-infected-removed model of infectious disease spread. The delay was due to the time-lag from transmission to case reporting. We simulated the number of students infected daily with and without school closure and evaluated the effectiveness.ResultsThe model with a 3-day delay from transmission to reporting yielded the best fit using R 2 (the coefficient of determination). This result suggests that the recommended period of school closure is more than 4 days. Moreover, the effect of school closure in the simulation of school closure showed the following: the number of infected students decreased by about 24% at its peak, and the number of cumulative infected students decreased by about 8.0%.ConclusionsSchool closure was an effective intervention for mitigating the spread of influenza and should be implemented for more than 4 days. School closure has a remarkable impact on decreasing the number of infected students at the peak, but it does not substantially decrease the total number of infected students.

Bacterial translocation to mesenteric lymph node predisposed patients with Crohn's disease undergoing laparotomy to systemic inflammatory response syndrome.

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Background: Japanese women in their 40s or older have been encouraged to attend breast cancer screening. However, the breast cancer screening rate in Japan is not as high as in Europe and the United States. The aim of this study was to identify psychological and personal characteristics of women concerning their participation in breast cancer screening using the Health Belief Model (HBM). In addition, the attributes of screening more easily accepted by participants were analyzed by conjoint analysis. Materials and Methods: In this cross sectional study of 3,200 age 20-69 women, data were collected by an anonymous questionnaire. Questions were based on HBM and personal characteristics, and included attitudes on hypothetical screening attributes. Data of women aged 40-69 were analyzed by logistic regression and conjoint analysis to clarify the factors affecting their participation in breast cancer screening. Results: Among responses collected from 1,280 women of age 20-69, the replies of 993 women of age 40-69 were used in the analysis. Regarding the psychological characteristics based on HBM, the odds ratios were significantly higher in "importance of cancer screening" (95%CI: 1.21-2.47) and "benefits of cancer screening" (95%CI: 1.09-2.49), whereas the odds ratio was significantly lower in "barriers to participation before cancer screening" (95%CI: 0.27-0.51). Conjoint analysis revealed that the respondents, overall, preferred screening to be low cost and by female staff members. Furthermore, it was also clarified that attributes of screening dominant in decision-making were influenced by the employment status and the type of medical insurance of the women. Conclusions: In order to increase participation in breast cancer screening, it is necessary to disseminate accurate knowledge on cancer screening and to reduce barriers to participation. In addition, the attributes of screening more easily accepted were inexpensive, provided by female staff, executed in a hospital and finished in a short time.

Background: The transmission potential of primary pneumonic plague, caused by Yersinia pestis, is one of the key epidemiological determinants of a potential biological weapon, and requires clarification and time dependent interpretation. Method: This study estimated the reproduction number and its time dependent change through investigations of outbreaks in Mukden, China (1946), and Madagascar (1957). Reconstruction of an epidemic tree, which shows who infected whom, from the observed dates of onset was performed using the serial interval. Furthermore, a likelihood based approach was used for the time inhomogeneous evaluation of the outbreaks for which there was scarcity of cases. Results: According to the estimates, the basic reproduction number, R 0 , was on the order of 2.8 to 3.5, which is higher than previous estimates. The lower 95% confidence intervals of R 0 exceeded unity. The effective reproduction number declined below unity after control measures were introduced in Mukden, and before the official implementation in Madagascar. Conclusion: While the time course of the latter outbreak could be explained by intrinsic factors and stochasticity in this remote and scarcely populated area, the former in Mukden suggests the possible continued chains of transmission in highly populated areas. Using the proposed methods, the who infected whom information permitted the evaluation of the time inhomogeneous transmission potential in relation to public health measures. The study also tackles the problem of statistical estimation of R 0 based on similar information, which was previously performed simply by counting the number of secondary transmissions regardless of time.

BackgroundA husband’s support during childbirth is vital to a parturient woman’s emotional well-being. Evidence suggests that this type of support enables a woman to feel more in control during labour by reducing maternal anxiety during childbirth. However, in Nepal, where childbearing is considered an essential element of a marital relationship, the husband’s role in this process has not been explored. Therefore, we examined whether a woman in Nepal feels more in control during labour when her husband is present, compared to when another woman accompanies her or when she has no support person.MethodsThe study participants were low risk primigravida women in the following categories: women who gave birth with their husband present (n = 97), with a female friend present (n = 96), with mixed support (n = 11), and finally, a control group (n = 105). The study was conducted in the public maternity hospital in Kathmandu in 2011. The Labour Agentry Scale (LAS) was used to measure the extent to which women felt in control during labour. The study outcome was compared using an F-test from a one-way analysis of variance, and multiple regression analyses.ResultsThe women who gave birth with their husband’s support reported higher mean LAS scores (47.92 ± 6.95) than the women who gave birth with a female friend’s support (39.91 ± 8.27) and the women in the control group (36.68 ± 8.31). The extent to which the women felt in control during labour was found to be positively associated with having their husband’s company during childbirth (β = 0.54; p < 0.001) even after adjusting for background variables. In addition, having a female friend’s company during childbirth was related to the women’s feeling of being in control during labour (β = 0.19; p < 0.001) but the effect size was smaller than for a husband’s company.ConclusionThe results show that when a woman’s husband is present at the birth, she feels more in control during labour. This finding has strong implications for maternity practices in Nepal, where maternity wards rarely encourage a woman to bring her husband to a pregnancy appointment and to be present during childbirth.