Surveillance for epidemic of enterovirus infections in Taiwan in 2008

Abstract

Background: The emergence of enterovirus 71 (EV71) in Taiwan in October, 2007 resulted in a large epidemic of hand-foot-and-mouth disease (HFMD) or herpangina in young children in 2008. EV71 patients may suffer from serious neurological complications or even deaths. The aims of this study were to describe the framework of the surveillance systems for enterovirus infections and to characterize this epidemic in Taiwan in 2008. Methods: At Taiwan Centers for Disease Control (Taiwan CDC), there were four systems established for the surveillance of enterovirus infections. First, we used the sentinel surveillance with more than 650 clinics for reporting the number of HFMD or herpangina in outpatient weekly. Second, the National Notifiable Disease Surveillance System (NNDSS) was used for reporting the hospitalized cases with severe complications. Third, the laboratory surveillance consisted of 13 contract laboratories and 286 clinics for testing and collecting samples, respectively. Fourth, Taiwan CDC cooperated with the University of Pittsburgh to develop a syndromic surveillance, which is called the Real-time and Outbreak Surveillance (RODS) system, covering 80% of the emergency visits nationally. The Taiwanese RODS system used the ICD-9-CM code of 074.0 and 074.3 to monitor enterovirus infections. A web-based decision support system for this epidemic was also developed for displaying the statistics and epidemic curves of the four systems in real time. Results: The epidemic started in week 11, peaked in week 25, and was subsiding gradually. The sentinel physicians reported 72,610 visits in one epidemic wave, which represents 18% of the ones nationally. 373 cases of severe complications (including 14 deaths) were reported through the NNDSS. Among those, 347 cases (93%) were EV71. A web-based system with automated updates daily for the public to browse the statistics and epidemic curves of the reported cases in the NNDSS was also released then. There were 11,150 specimens tested and 3,724 (33%) enterovirus isolated in the laboratory surveillance. The three most isolated types were Coxsackie A2 (CA2), EV71 (B5 was the major subtype), and Coxsackie B4 (CB4). The real-time data from the RODS helped us better track the trend of the epidemic. During the large epidemic of enterovirus infections, our established surveillance systems are helpful for informing decisions about control measures, resource allocation, and risk communication in real time. Abstracts for SupplementInternational Journal of Infectious DiseasesVol. 14Preview Full-Text PDF Open Archive