The application of the concentration ratio and the circular distribution in the analysis of seasonality of infectious diseases.

Objective This study was conducted to gain insight into the characteristics of sea-sonal distribution of common infectious diseases in the city of Wenzhou，providing a scientific ba-sis for the surveillance，prevention and control of the diseases．Methods The concentration ratio and the circular distribution were used for the analysis of seasonality of infection diseases．Results This study showed that occurrence of epidemic encephalitis B was strictly seasonal，with cholera highly seasonal，and epidemic cerebrospinal meningitis，dysentery and measles obviously seasonal in the city of WenzhOU．There was a certain seasonality in the prevalence of malaria and whoop-ing cough with other infection diseases poor in seasonality in the city．Conclusion The different measures should be taken based on the characteristics of seasonal distribution of specific infecfious diseases for the effective prevention and control of the diseases．