Epidemiological analysis of an outbreak of bacillary dysentery

Objective　This analysis was made to investigate the epidemiological characteristics and the transmission routes of the bacillary dysentery outbreak in order to control the epidemic. Methods　Field epidemiological investigation was conducted to collect samples and culture the isolates. Results During the 32 days outbreak, a total of 121 cases occurred with the attack rate of 3.66%. With several sub peaks of incidence at the interval of 1-3 days, the incidence peaked at 10th day after the first case. Cases below 15 years of age accounted for 47.93% of the total case. Family clustering was found. Shigella flexneri 2a was detected from 15 stool samples and 1 fly sample. Conclusion　The outbreak was confirmed to be caused by Shigella flexneri 2a and transmitted through casual contact.