This area is one of most dengue outbreaks in southern Thailand. This district is about 520.249 km 2 with 23 sub-districts, 125 villages, 84070 houses, and 266,619 populations (Muang Nakhon Si Thammarat District Register Office 2009). MuangNakhonSi Thammarat,Thailand Figure 2. Map of Thailand and study site at Nakhon Si Thammarat province, Thailand