Dengue fever surveillance in China, 2006

Objective　To analyze the surveillance data of dengue fever in China (excluding Hong Kong, Macao and Taiwan) for providing evidence for the prevention and control of the disease. Methods　Descriptive epidemiological method was used to statistically analyze the dengue fever data reported through the National Network Direct Reporting System and the surveillance results in 2006. Results　In 2006, a total of 1044 cases of dengue fever were reported in 14 provinces, and no death case was reported. Except the indigenous cases in Guangdong，the cases in other areas were imported ones, which occurred all the year around and were mainly from South-East Asia and America regions. Cambodia, Myanmar and Singapore were the first three countries where the most imported cases came from. Vector surveillance to Aedes indicated that Breteau Index (BI) was above 5 (the safety level) in all surveillance spots in Guangxi, Hainan and Yunnan, and in most surveillance spots in Fujian (86.7%) and Guangdong (55.8%), especially during June to October，the BI was much higher. The vector in Fujian, Guangdong, Yunnan and Guangxi was Aedes albopictus, and the vectors in Hainan were Aedes albopictus and Aedes aegypti. The positive rate of dengue fever antibody among healthy people at surveillance spots ranged from 0% to 14.5%. No dengue virus nucleic acids was detected and no dengue virus was isolated from the vector Aedes at the surveillance spots which conducted etiological detection. Conclusion　Mosquito vectors and susceptible population exist in the monitored provinces of southern China, imported case in summer and autumn may cause indigenous outbreak. It is important to set up sensitive dengue fever surveillance system for the early-warning, detect cases early and conduct mosquitoes control activity.