Establishment and evaluation of cholera surveillance system in Guangxi

Objective　The study was conducted to early detect natural focus and to control the incidence and spread ofcholera by establishing a surveillance system in Guangxi. Methods　Thirty selected areas were classified and managed, and theobjects and tasks were confirmed and implemented; the surveillance results of 8 years were analyzed and evaluated. Results　Atotal of 561 147 samples were tested during 8 years; the total detection rate of cholera was 0.051%, and the culture positiverates in patients with diarrhea, suspected cases, high risk population, water, food and other environmental samples were respectively 0.061%, 0.032%, 0.099%, 0.055% and 0.115%. All Vibrio cholera isolated between 1999 and 2001 were epidemic strains or toxic strains, while between 2002 and 2006 all the Vibrio cholera strains were only isolated from environmental samples and 92.31% of them were non epidemic or non toxic strains. For the samples collected in the three types of areas, the culture positive rates were respectively 0.061%, 0.043% and 0.134%. All the first reported cases in the three years when epidemics occurred were detected by the surveillance system, and 93.23% cases of vibrio cholera were detected at the diarrhea clinics. The majority of positive cases of Vibrio cholera were found in epidemic areas, where the culture positive rate (0.378%) was higher than that in non epidemic areas (0.005%). The overall positive rate was positively correlative with the epidemic intensity, which was consistent with the epidemic situation. Conclusion　The sensitivity of case detection at diarrhea clinics has been improved. The data collected through the surveillance system reflected the true prevalence and provided effective directions to control policy making. It is urgently necessary to establish more diarrhea clinics and to make proper guidelines for implementing the surveillance in medical institutions at all levels.