Epidemiology and etiological surveillance of hand-foot-mouth disease in Suining City, Sichuan Province, 2011-2015

Objective To investigate the epidemiological characteristics and virus constitution of hand-foot-mouth disease in Suining City, and analyze the high risk factors of severe cases. Methods The case cards of hand-foot-mouth disease in Suining City from 2011 to 2015 derived from infectious disease reporting information management system and the etiological monitoring data provided by laboratory of Suining Center for Disease Control and Prevention were analyzed. The general epidemic situation and the pathogenic classification were described, and the risk factors of severe hand-foot-mouth disease were explored by Logistic regression. Results The annual average incidence, severe rate, mortality rate and severe mortality rate of hand-foot-mouth disease in Suining City during 2011 and 2015 were 65.82/100 000, 4.83‰, 0.19‰ and 38.46‰, respectively. Two incidence peaks respectively were from March to May and from October to November. Age of onsetwas mainly concentrated under 3 years old (9 133 cases, 84.84%) , and the male and female ratio was 1.59:1 (χ2=108.72, P<0.01) . The crowd classification was mainly concentrated in the scattered children (8 168 cases, 75.93%) , followed by preschool children (2 362 cases, 21.96%) , while the severe cases was mainly scattered children (47 cases, 90.38%) .There were significant differences in the severe rates of hand-foot-mouth disease among different crowd classification, which had statistical significance (χ2=11.95, P<0.05) . There were 730 samples collected in 5 years, in which 413 samples were positive (56.58%) , and other enterovirus was the dominant strain (positive rate was 34.66%) , followed by enterovirus 71 (positive rate was 14.25%) . Multivariate analysis showed that the risks of severe cases with enterovirus 71 and coxsackievirus A16 positive were increased 3.44 times and 4.74 times respectively. Conclusions The incidence of hand-foot-mouth disease in Suining City is increasing year by year and with obvious seasonality. The focus group of hand-foot-mouth disease is of children under 3 years old. The enterovirus 71 and coxsackievirus A16 infection will increase the risk of severe cases. Key words: Hand, foot and mouth disease; Epidemic surveillance; Epidemiological characteristics; High risk factors