Epidemiologic Analysis of Scarlet Fever Reported from Eastern Taiwan during 2000-2006

Jau-Hwa Liang1, Yann-Ling Lin3, Jinq-Fen Ke1, 2, Chyi-Fuu Li1, Yeong-Cherng Li1, 3, Wen-Yi Shy4

2010 Vol.26 NO.20

Correspondence Author： Yeong-Cherng Li

Abstract：

Scarlet fever is a respiratory disease caused by group A (beta hemolytic) streptococci. The surveillance data shows that the number of confirmed scarlet fever cases appeared to be an increasing trend in recent years in Taiwan. This study conducted an epidemiologic analysis of scarlet fever occurred in eastern Taiwan to understand the characteristics and trend of disease occurrence.
This study extracted data, by using Business Objects (BO) software, from the Communicable Disease Surveillance Database in Taiwan Centers for Disease Control (Taiwan CDC) and the epidemiologic investigation database in Sixth Branch of Taiwan CDC. These data were calculated and mapped by applying the software of Microsoft Excel 2003, SAS9.1 version, and were expressed as number of cases and proportion for various variables, which subsequently were described and analyzed by performing a variety of statistical tests, such as Chi-square for trend test and other relevant test.
A total of 183 cases of scarlet fever were confirmed in eastern Taiwan during 2000-2006, including 50 cases in Haulien County and 133 cases in Taitung County. The secular trend shows that the annual number of scarlet fever cases for both male and female were increasing year by year, and the incidence rate in male has overridden that of female since 2004. Children at the age of 5-6 years old had the highest incidence rate, and May was the peak month of the temporal trend for disease occurrence. Symptom analysis shows that, for cases with only one symptom, fever was the symptom with the highest number of the cases, and, for cases with multiple symptoms, fever combined with skin rash shared the largest part among the cases. The average time interval between the date of onset and date of diagnosis was 4.02 days. Cases diagnosed within 5 days after the date of onset accounted for 80.9% of total cases.
In this study, except the events of cluster infections, no other factors that may have led to the increase of annual number of scarlet fever cases in eastern Taiwan during 2000-2006 was observed. Because this study did not have data on molecular epidemiology, it is unknown that the increase of number of scarlet fever cases was associated with the emergence of newly and highly pathogenic strains. In the future, homology analysis of the strains could be included as part of data for the study to identify the exact strains circulated in eastern Taiwan. The factors possibly leading to the increase of number of scarlet fever cases shall be explored.