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 se...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.展开更多
基金supported by JST-CREST, JSPS-KAKENHI (No. 26241025)MEXT-GRENE
文摘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.
