On May 28, 2014, the Taiwan Centers for Disease Control (Taiwan CDC) announced this summer’s first indigenous dengue case in a 45-year-old male who resides in Caoya Village, Qianzhen District, Kaohsiung City and has no history of overseas travel. On May 24, when he developed symptoms, including fever, fatigue, muscle ache and malaise, he sought medical attention at a clinic. On the following day, when his symptoms persisted, he sought further medical assistance at a hospital. On May 26, the case was reported to the health authority by the hospital as a suspected case of dengue fever. Subsequently, infection with dengue fever was confirmed in the case by Taiwan CDC. The local health authority has implemented a number of prevention measures to prevent further spread of the disease, including conducting an expanded epidemiological investigation, investigating the mosquito density in and around the case’s residence and places frequently visited by the case, conducting a thorough cleaning of vector breeding sites, and spraying insecticide. According to the epidemiological investigation, three other residents in the same district have developed suspected symptoms pertaining to dengue fever and infection with the disease was later confirmed in all three of them, indicating the occurrence of a cluster of dengue cases. Currently, the local health authority is reinforcing the removal of vector-breeding sites to prevent further transmission of the virus.

According to statistics compiled by Taiwan CDC, thus far this year, as of May 28, a cumulative total of 18 indigenous dengue cases have been confirmed in Taiwan. Of the indigenous cases, 14 were from local outbreaks that occurred last year and their illness onsets were all before February 6. On the other hand, a total of 65 imported dengue cases have been confirmed in Taiwan, including 34 from Indonesia, 17 from Malaysia, 6 from the Philippines, 3 from Singapore, 2 from Nauru and 1 respectively from Thailand, Cambodia, and French Polynesia.

As we have entered summer and the rainy season, it is very likely to see a significant increase in the number of water-holding containers and an increase in the mosquito density, facilitating the transmission of dengue fever. Since both warmer temperature and increased rainfall favor the growth of vector mosquitoes, removing vector-breeding sites remains the most effective way to prevent dengue fever. Hence, the public is urged to thoroughly clean and remove any indoor and outdoor water containers and vector breeding sources around their residences, and recycle all unwanted containers to prevent spread of the virus. In addition, according to Article 70 of the Communicable Disease Control Act, anyone who refuses, evades or obstructs disease control measures such as inspection decided by competent authorities or fails to notify the competent authorities of the presence of vector breeding sites that is later identified by competent authorities or clean up vector breeding sites as requested by competent authorities may be fined NT$ 3,000 up to NT$ 15,000.

Taiwan CDC reminds the public that we have entered the dengue season. Travelers planning to visit high risk areas are advised to take personal precautions against mosquito bites throughout the trip in order to prevent dengue infection and further spread of the disease. Physicians are advised to be vigilant for suspected cases, inquire about such patients’ travel history, and notify any suspected cases to the health authority immediately to facilitate implementation of subsequent measures that prevent further transmission of the disease. If symptoms such as fever, headache, retroorbital pain, myalgia, arthragia, and rash develop after returning to Taiwan from an area at high risk for dengue fever, please seek immediate medical attention and inform the doctor of any relevant medical history, recent travel history and activity to facilitate prompt diagnosis and case reporting. For more information on dengue fever, please visit the Taiwan CDC website at http://www.cdc.gov.tw or call the toll-free Communicable Disease Reporting and Care Hotline, 1922 (or 0800-001922).