Major Epidemics of Dengue in Taiwan in 1981-2000: Related to Intensive Virus Activities in Asia

Major epidemics of dengue fever/dengue haemorrhagic fever/dengue shock syndrome (DF/DHF/DSS) in Taiwan in the last 20 years were strongly associated with imported cases. The data analysis showed that three major epidemics including the first outbreak of DF in Hsiao-Liu-Chiu in 1981 since 1950s, the largest epidemic of DF in Pingtung and Kaohsiung in l987-l988, and the most important epidemic of DHF in Tainan in 1998, had statistically significant association with the increasing numbers of dengue cases in several Asian countries before or during the epidemic (p=0.028, p=0.043, p=0.08, respectively). Imported dengue cases in Taiwan were primarily travellers who had come from Thailand, Indonesia, the Philippines, Myanmar and Malaysia. The earlier indigenous dengue cases in Taiwan always used to appear later than the peaks of monthly-distributed dengue cases in those countries. On the other hand, active surveillance, epidemiological investigation, mosquito control activities and effective public health administration at various levels indeed reduced the number of confirmed indigenous dengue cases in l996 and l997. Taiwan’s experience in surveillance further proves the feasibility of avoiding a large-scale epidemic of DHF/DSS as well as hyper-endemicity of dengue viruses. International collaboration in surveillance, epidemic information exchange, and statistical analysis can play an important role in the prevention and control of DF/DSS in the future.