2001 年 67 巻 1 号 p. 28-40
To characterize the features of epidemic patterns of infectious gastroenteritis among 47 pre-fectures in Japan, we have introduced the use of two new statistical methods, the modified Lorenz curve and the modified Gini index, which are usually used in economics and demogra-phy. These statistical methods are reported to be suitable for the analysis of seasonal variations and were used in conjunction with the cumulative percentage curves. We attempted to apply these new methods using data collected from the surveillance of infectious diseases in Japan. The results suggest that cumulative percentage curves may be useful for the monitoring of in-fectious gastroenteritis epidemics in several prefectures. The modified Lorenz curve and the epi-demic index, namely the modified Gini index, may also be useful as standards for comparing the epidemic features of infectious diseases for epidemic patterns that are characterized by tempo-ral changes within the same prefecture. Such application could enable essential differences among different prefectures and different infectious diseases to be described.
