TAIPEI (Taiwan News) — Taiwan health authorities are on alert for a possible spike in dengue fever cases due to the rainfall accumulation from Typhoon Krathon.
The week following a typhoon is typically when the vector mosquito index increases significantly, posing a challenge to sanitation crews in removing standing water and spraying to prevent mosquito breeding.
According to Centers for Disease Control (CDC) data, the dengue fever cluster in New Taipei has reached 57 cases as of Oct. 1. CDC Spokesperson Lo Yi-chun (羅一鈞) said the number of new cases reduced significantly, though health officials are now facing a major challenge after Typhoon Krathon, per BCC.
Hwang Ji-sen (黃基森), professor emeritus at the University of Taipei Department of Earth and Life Science, said dengue fever cases and deaths in Taiwan in the past 10 years are closely correlated to typhoons. According to Huang, the recent typhoon brought rainfall exceeding 1,000 mm, with outdoor water containers accumulating 100 cm of water, which will not easily evaporate due to heat and sunshine by the end of the year.
Rainfall accumulation in outdoor containers must be cleaned manually. Huang reminds the public to clear accumulated water from containers like unused flower pots or flower beds after a typhoon to prevent mosquito breeding.
Hwang said that when Typhoon Fung-wong hit Taiwan in 2008, a dengue fever epidemic broke out in Kaohsiung, resulting in 15,492 cases, the highest number since 1976.
Typhoon Soudelor in 2015 led to a major increase in vector mosquitoes, with the dengue fever epidemic in Tainan setting two records that year. The first record was the number of cases, which topped 43,419, and 228 deaths.
Typhoon Maria in 2018 also led to heavy rain and stagnant water. Hwang said this caused 113 cases in Taichung, which had never had dengue fever.
Typhoon Doksuri and Typhoon Khanun in the summer of 2023 led Tainan to record more than 20,000 dengue fever cases, and Yunlin County experienced more than 700 cases, setting a record for the highest number of dengue fever cases in an area without the vector mosquito, Aedes aegypti.
Health authorities are monitoring the dengue fever situation in New Taipei, which has many mountainous areas and parks as well as public markets and residences. Hwang suggested people within the community should be mobilized to clear stagnant water from containers.
Hwang said the vector mosquito that caused the dengue fever cluster in New Taipei is the Asian tiger mosquito (Aedes albopictus), which is an outdoor species found in mountainous areas and elsewhere. The female mosquito of this species is especially aggressive during the day.
