Epidemiological analysis of dengue fever in Leizhou, Zhanjiang, Guangdong province in 2007

Objective　The study was conducted to analyze the epidemiological characteristics and risk factors of dengue fever in Leizhou, Zhanjiang, Guangdong in 2007. Methods　Descriptive epidemiological analysis was performed on the basis of epidemic data, laboratory findings and entomophily records with respect of dengue fever in Leizhou, Zhanjiang in 2007. Results　A total of 205 cases of dengue fever were reported in Leizhou, Zhanjiang in 2007, without death cases. The annual incidence was 14.8/lakh. Three towns were involved in the epidemic, 91.2% of cases(187/205) occurring in Wushi town where two peaks presented within the duration from Sep. 30 to Nov. 22. The men to women ratio was 1∶1.11. Affected cases were mostly aged between 30-60 years (63.9%); house workers, unemployed ones and students(84.9%) constituted the occupational predominance among the affected cases, and the clinical symptoms included fever(99.4%) and headache(76.5%). Dengue virus Type I was isolated from 18 patientsblood serum, of which one genetic sequence was highly homologous（99.8％） with other case found in Zhuhai in 2007. Aedes aegypti was the major vector in the city, and household water tanks were the breeding ground. Conclusion　The epidemic of dengue fever in Leizhou, Zhanjiang in 2007 was caused by virus sero type Ⅰdengue virus, and Aedes from household water tanks constituted the causative agents.