Epidemiological and Clinical Analysis of Melioidosis in Taiwan, 2006-2010
Yu-Ling Chou1、Christine Ding-Ping Liu1、Ji-Jia Huang1、Donald Dah-Shyong Jiang2
2013 Vol.29 NO.9
Correspondence Author： Donald Dah-Shyong Jiang
In order to understand the incidence rate, demographic characteristics, clinical symptoms, and underlying diseases of melioidosis, and to analyze the correlation between the rainfall and the occurrence of melioidosis, we conducted a study by using the data of confirmed melioidosis cases reported to the National Notifiable Communicable Disease Surveillance System and the Notifiable Communicable Disease Investigation System from 2006 to2010.
The melioidosis patients identified during 2006-2010 mainly clustered in Kaohsiung- Pingtung and southern regions in Taiwan, with an incidence rate of 7.8 and 3.2 per 100,000 population, respectively. A total of 175 melioidosis cases were confirmed, the male to female ratio was 4:1, the age group with most number (48.6%) of the patients was 40-59 years, and the majority (49.1%) of them was either unemployed or retired. The most commonly seen symptom was fever (67.4%). Of the 175 cases, 138 (78.9%) have been admitted to a hospital, 41 (23.4%) were fatal cases, 141 (80.6%) had a history of underlying diseases (mainly diabetes, 70.9%, and hypertension, 39.7%), and 33 (18.9%) had a direct contact with contaminated soil or flooding water.
The melioidosis infection occurs most often during July-September. Particularly, the melioidosis cases are most likely to occur following the flooding because of extremely heavy rain brought by typhoon. During 2006-2010, the monthly cumulative rainfall and the monthly number of cases of melioidosis occurring in the same month and the following month presented weak correlation that were statistically significant in Kaohsiung areas, and the correlation coefficient was 0.417 and 0.395, respectively. In Tainan areas, the weak correlation (correlation coefficient: 0.289) that was statistically significant was also found between the monthly cumulative rainfall and the monthly number of cases of melioidosis occurring in the same month. The regression analysis indicated that the incidence of melioidosis had a statistically significant correlation (p <0.001, respectively) with both the occurrence of extremely torrential rainfall and torrential rainfall in Kaohsiung area. The monthly number of melioidosis cases occurred following the extremely torrential rainfall or torrential rainfall had an average of 8 and 7 more cases than those in the months without extremely torrential rainfall and torrential rainfall, respectively. In Tainan area, the incidence of melioidosis also had a statistically significant correlation with the occurrence of both extremely torrential rainfall and extremely heavy rainfall (p < 0.001, respectively). The monthly number of cases of melioidosis in months with extremely torrential rainfall or extremely heavy rainfall increased with an average of 7 and 4 cases, respectively, as compared with those in months without extremely torrential rainfall or extremely heavy rainfall.