[Surveillance on the health status regarding vector-borne disease among people living in the Three Gorges Reservoir Area (1997 - 2009)].

Objective: To evaluate the impact on the health status of population in the area where the 'Three Gorges Reservoir Water Storage Project' had been operated and to provide references for the development of related disease control strategies.

Methods: In the Three Gorges Reservoir Area, 17 towns/streets in nine counties were chosen as surveillance points. Data on surveillance program would include infectious diseases, birth, death, biological agents etc.

Methods: related to time and spatial analysis and the comparison on pre- and post-water storage were used to analyze and describe the long-term changing trend of meteorological index, distribution of biological agent and diseases, and human health status. Relationships between number of infectious diseases and media biological density and meteorological parameters were also analyzed.

Results: When the water storage program came into being in 2003, the indoor (2.22%) and outdoor (2.76%) densities of rats were significantly lower than pre-water storage period (indoor 4.38% vs. outdoor 4.43%) and the annual average density of mosquito (35.09 mosquitoes per room and per hour) was also lower than before (54.24 mosquitoes per room and per hour). The incidence rates of encephalitis B, malaria, leptospirosis, and hemorrhagic fever had reduces 22.88%, 84.85%, 95.03% and 81.82% than before. The incidence rates of malaria, leptospirosis, and hemorrhagic fever were all below 0.4/100 000 and the incidence of encephalitis B was below 2/100 000. The average infant mortality was 11.83‰. The annual infant mortalities, after adjusted by missing report numbers, were between 13.07‰ and 23.88‰ which were lower than the national annual average level. The thirteen year standard mortalities were 3.77‰ - 5.12‰, with the total rate lower than the national average level in the same years.

Conclusion: In 2003, the incidence rates of malaria, encephalitis B, leptospirosis, epidemic hemorrhagic fever kept going down in the surveillance sites in the Three Gorges Reservoir Area, and the overall population's health status was well enough to show that there was no negative impact on the health status of population living in the area after the water storage project was inplemented.