Comparative assessment of primary and secondary infection risks in a norovirus outbreak using a household model simulation  

作　　者：Fuminari Miura Toru Watanabe Kozo Watanabe Kazuhiko Takemoto Kensuke Fukushi 

机构地区：[1]Department of Urban Engineering, Graduate School of Engineering, the University of Tokyo [2]Department of Food, Life and Environmental Sciences, Faculty of Agriculture, Yamagata University [3]Department of Civil and Environmental Engineering, Ehime University [4]Institute for the Advanced Study of Sustainability, the United Nations University [5]Todai Institutes for Advanced Study(TODIAS), Integrated Research System for Sustainability Science(IR3S), The University of Tokyo

出　　处：《Journal of Environmental Sciences》2016年第12期13-20,共8页环境科学学报（英文版）

基　　金：supported by JST-CREST, JSPS-KAKENHI (No. 26241025);MEXT-GRENE

摘　　要：Diarrheal diseases can be transmitted via both primary infection due to exposures to contaminated materials from the environment and secondary infection due to person- to-person contacts. Usually, the importance of secondary infection is empirically assessed by fitting mathematical models to the epidemic curves. However, these empirical models may not be applicable to other epidemic cases because they are developed only for the target epidemics and they don＇t consider the detail routes of infection. In our previous study, we developed a theoretical model taking into account the various routes of infection that commonly occur in households （e.g., shaking hands, food handling, and changing diapers）. This model was made flexible and applicable to any epidemics by means of adjusting model parameters. In this study, we proposed a new index ＂Vulnerability indicator to secondary infection （VISI）＂, which expressed a ratio of secondary infection to primary infection risks and calculated this index in a simulated norouirus （NOV） epidemic that involved I0,000 households. The results demonstrated that households composed of more than three members including infant（s） had much higher levels of VlSl （5-45） than two-member-households with VlSI （0.1-4）. These results concluded that the infants were likely to be a hub of secondary infections in highly dense families and therefore careful handling of diapers was deemed indispensible in such families to effectively control the secondary infections.Diarrheal diseases can be transmitted via both primary infection due to exposures to contaminated materials from the environment and secondary infection due to person- to-person contacts. Usually, the importance of secondary infection is empirically assessed by fitting mathematical models to the epidemic curves. However, these empirical models may not be applicable to other epidemic cases because they are developed only for the target epidemics and they don＇t consider the detail routes of infection. In our previous study, we developed a theoretical model taking into account the various routes of infection that commonly occur in households （e.g., shaking hands, food handling, and changing diapers）. This model was made flexible and applicable to any epidemics by means of adjusting model parameters. In this study, we proposed a new index ＂Vulnerability indicator to secondary infection （VISI）＂, which expressed a ratio of secondary infection to primary infection risks and calculated this index in a simulated norouirus （NOV） epidemic that involved I0,000 households. The results demonstrated that households composed of more than three members including infant（s） had much higher levels of VlSl （5-45） than two-member-households with VlSI （0.1-4）. These results concluded that the infants were likely to be a hub of secondary infections in highly dense families and therefore careful handling of diapers was deemed indispensible in such families to effectively control the secondary infections.

关 键 词：Norovirus Quantitative microbial riskassessment Secondary infection 

分 类 号：R51[医药卫生—内科学]