Study on the Quality of Dengue Fever Surveillance in Taiwan Area

Sau-Yu Liao, Che-Chieh Yen, Chi-Ching Huang

2010 Vol.26 NO.24

Correspondence Author: Sau-Yu Liao


Dengue fever is one of the category 2 communicable diseases in Taiwan. The surveillance of dengue fever mainly relies on the notification by physicians who diagnosing the suspected cases, as required by the Communicable Disease Control Act. Another approach for case finding is fever screening at border entry point for detecting imported cases. Therefore, to detect dengue epidemic in time will be dependent on the immediate notification of physicians in medical institutions and a well established and operating surveillance system. To identify case at its early stage will be helpful to the action taken subsequently for disease control. This study used the data of dengue fever collected in the recent five years (2004-2008) from the National Notifiable Communicable Disease Surveillance System Database to analyze the timeliness of notification of dengue cases. The results show that 87.2% (9,209/10,563) of cases were diagnosed as suspected dengue fever within seven days after onset of symptoms and the median interval from the date of onset to the date of diagnosis was four days ; 0.4% of the total cases was not reported within the time required by the regulation ; and the median interval from the date of notification to the date of confirmation was eight days.
This study estimates that the overall notification rate of dengue fever among medical institutions during 2006-2007 was 86.6% (3,528/4,074). Data from outpatient units show that the average notification rate was 83.0% (2,192/2,641), with the highest rate found in medical center, then, in descending order, regional hospitals, area hospitals, and clinics. The notification rate was only 47.7% (199/417) in clinics. The highest notification rate (86.6%) was found in southern Taiwan area and the lowest (42.9%) in eastern Taiwan area. Data from inpatient units indicate that the average notification rate was 95.4% (2,428/2,545). The notification rate in different levels of hospitals (including medical center, regional hospitals, and area hospitals) was all higher than 90%. The notification rate for inpatient units was commonly higher than outpatient units in each of the administrative area.