Epidemiological characteristics of bacillary dysentery in Shijiazhuang, Hebei province, 2001 - 2008

Objective To analyze the epidemiological characteristics of bacillary dysentery in Shijiazhuang, Hebei province from 2001 to 2008. Methods The incidence data of bacillary dysentery from 2001 to 2008 were derived from the China Information System for Diseases Control and Prevention, with which the population, regional and temporal distribution of patients were analyzed. Results The average incidence rate of bacillary dysentery was 33.02/lakh in Shijiazhuang from 2001 to 2008. The cases were mainly concentrated in the 0-year-olds with an incidence rate of 161.4/lakh, followed by the 5-year-olds with an incidence rate of 78.2/lakh and those older than 10, whose incidence rate was 30.5/lakh; the lowest incidence rate, 13.1/lakh, was present in patients above 70 (2 =25 162.75, P=0.00). Male patients were more than female ones (2=1147.42, P=0.00). Farmers were primarily affected (2=9086.34, P=0.00), accounting for 35.8%, followed by scattered children and students, accounting for 22.2% and 17.0%, respectively (2=9086.34, P=0.00). The incidence rate of bacillary dysentery in rural areas was significantly higher than the urban counterpart from 2001 to 2008 (2=6995.77,P=0.00). While bacillary dysentery was present throughout the eight years, seasonality was evident as cases were growing from May and June, peaking in July and August, declining beyond October and landing from December to February in the next year, which constituted the noticeable decreasing trend of bacillary dysentery incidence from 2001 to 2008 (r=-0.9156, P=0.00). Conclusion Recently, patients of bacillary dysentery were mostly under the age of 10, males outnumbering females. The incidence was higher in rural areas than in urban ones, and farmers and scattered children were the major victims. Peaking in July and August each year, the incidence was gradually decreasing by year.