2.2. Data collection
Data on the monthly number of notified dengue cases in Dhaka City were obtained from the Directorate General of Health Services (DGHS) from January 2000 to December 2010. As dengue is a notifiable disease in Bangladesh, any case detected based on the World Health Organization (WHO) clinical criteria must report to the DGHS by the Hospital. According to the WHO clinical criteria, a dengue case was defined by the presence of acute fever accompanied by any two of the following clinical symptoms such as headache, myalgia, arthralgia, rash, positive tourniquet test and leucopenia (WHO, 2000). We also obtained monthly weather data on maximum, mean and minimum temperature, relative humidity and rainfall from Bangladesh Meteorological Department (Dhaka, Bangladesh) between January 2000 and December 2010. Population data were collected from Bangladesh Bureau of Statistics (BBS).