The swine influenza A (H1N1) virus had spread rapidly throughout the world in 2009. Japan's Ministry of Health Labor and Welfare collected detailed data for each patient at the beginning of the outbreak in Japan. We described the characteristics of H1N1 infections in three big cities in Japan and examined the correlation between factors using multiple correspondence analysis method. We obtained patients data from governmental published data through internet from May 8 to June 30, 2009. We collected patients' socio-economical background and categorized most likely source of infection into three groups. We used multiple correspondence analysis method. The collected data showed that 57.9% of 908 patients were of age 11 to 20. Based on the numerical data, we made multiple correspondence analysis map. This map showed each area's patients characteristics simultaneously. This article extended the sociological thinking into the field of emerging infectious diseases. We had many H1N1 patient data. Each data showed a few meanings, but each data's correlation was sometimes complicated and hard to understand. The multiple correspondence analysis maps were strong tool for understanding the relationship factors of diseases.
- Swine influenza A(H1N1)