Epidemiology and etiology of hand foot and mouth disease outbreaks in Shenzhen, 2009-2013

Objective To understand the epidemiological and etiological characteristics of hand foot and mouth disease (HFMD) outbreaks in Shenzhen, Guangdong province, and provide scientific evidence for HFMD prevention and control. Methods The incidence data of HFMD outbreaks in Shenzhen were collected from national public health emergency information system and Shenzhen communicable disease information system for descriptive epidemiological analysis. Results From January 2009 to December 2013, 365 HFMD outbreaks were reported in Shenzhen, accounting for 21.1% of total communicable disease outbreaks (365/1727), in which 16 were classified as public health emergencies, accounting for 6.8% of total public health emergencies (16/236). The annual incidence peak of HFMD occurred during March-June, but sub-peak occurred in November 2011 and in September 2012. Up to. 93.7% of outbreaks (342/365) occurred in child care settings, and 68.2% of outbreaks (249/365) were reported in urban area, but the outbreaks which were identified as public health emergencies mainly occurred in suburban area (68.8%, 11/16). Totally 141 outbreaks (38.6%) were reported within 1 day. The attack rate ranged from 0.59% to 100% (median: 10.3%), and the durations of outbreaks ranged from 1 to 41 days (median: 3 days). Correlation analysis indicated that non-timely reporting was positively related with the duration and cases number of the outbreak significantly (P0.05), with r of 0.621 and 0.416 respectively. EV71 was predominant in 2009 and 2010 (39.5%, 48.4%), while EV71, Cox A16 and other enteric viruses shared similar proportion in 2011 (27.6%, 23.5%, 22.4%), and other enteroviruses became predominant in 2012 and 2013 (39.4%, 28.2%). Conclusion Early response to HFMD outbreak could effectively decrease public health emergency. Child care settings were the major places where HFMD outbreaks occurred in Shenzhen. The reporting management should be strengthened in suburban area, and timely reporting and response are essential for the control of HFMD outbreak.