The first epidemic of dengue in China associated with significant severe and fatal hemorrhagic disease which met the World Health Organization case defintion occurred on Hainan Island in1985—1986.The epi-demic began in Zhan County in September1985,spread throughout the coastal areas,and ultimately involved 13 counties and cities of the island in1986.The mosquito vector was Aedes aegypti.the morbidity associated with dengue infection on Hainan Island was1,913 per100,000 residents,with a case fatality raie of0.25%. The first epidemic of dengue in China associated with severe severe and fatal hemorrhagic disease which met the World Health Organization case defintion occurred on Hainan Island in1985-1986. Epi-demic began in Zhan County in September 1985, spread throughout the coastal areas and ultimately ultimately The 13 counties and cities of the island in 1986. The mosquito vector was Aedes aegypti. the morbidity associated with dengue infection on Hainan Island was 1,913 per 100,000 residents, with a case fatality rate of 0.25%.