On May 16, 2017, the Taiwan Centers for Disease Control (Taiwan CDC) announced this year’s first indigenous dengue case confirmed in Taiwan though the case’s symptom onset date cannot rule out the possibility of the case being imported. The case is a 27-year-old female who resides in Kaohsiung City. On May 5, she developed headache, fever, muscles ache, joint pain, retroorbital pain and loss of appetite. When her symptoms persisted, she respectively sought medical attention on May 6, 8 and 9. On May 10, the case was reported to the health authority as a suspected dengue case and was transferred to a hospital for further medical attention. The number of days between her symptom onset date and the date of reporting her case to the health authority is 5. Infection with dengue fever was confirmed in the case on May 16. As of now, the case is currently hospitalized in an isolation ward for treatment. To prevent the further spread of the disease, the local health authority has implemented various prevention measures upon receiving the report of the case, including cleaning of vector breeding sites, investigating the mosquito population density around the case’s residence and workplace, monitoring and following up on the case’s close contacts, providing the public with relevant health education, and advising physicians working in the healthcare facilities in the neighborhood to heighten vigilance for suspected cases and reinforce case-reporting.

According to the epidemiological investigation, the case had not been infected with dengue fever previously and has no medical history of chronic conditions. The case’s primary areas of daily activities include places around her residence and her workplace. So far, none of the 4 family members residing in the same household with the case and the neighbors in the same community have developed suspected symptoms. Nevertheless, during the expanded blood testing for the community residents, one asymptomatic case suspected of dengue was identified. A second specimen collection has been scheduled on May 20 for further confirmation. The Kaohsiung City Government Department of Health has implemented relevant measures to prevent further transmission.

Recently, the number of suspected indigenous dengue cases has been on the rise. Thus far this year, a cumulative total of 1 indigenous dengue case and 79 imported dengue cases have been confirmed in Taiwan. Imported cases were mostly from Southeast Asian countries, including Malaysia, Indonesia and Vietnam. Last year, a cumulative total of 380 indigenous dengue cases and 363 imported dengue cases were confirmed.

In terms of international dengue surveillance, dengue activity in Vietnam and Laos has been on the rise recently. As of late April 2017, over 26,000 dengue cases, including 7 deaths, and 727 cases have been respectively reported in Vietnam and Laos. Laos has reported a higher number of cases this year compared to the same period last year. On the other hand, Singapore, Thailand and Cambodia have reported a relatively lower level of dengue activity this year compared to the same period last year. In addition, dengue activity in Sri Lanka has continued to fluctuate. As of early May 2017, Sri Lanka has reported over 44,000 cases, which is the highest during the same period since 2010.

As summer is fast approaching, the temperature in Taiwan is gradually increasing and rain has continued to fall across Taiwan, Taiwan CDC urges the public to empty and clean any potential vector breeding sites in and around the home periodically in order to prevent dengue transmission. Travelers planning to visit areas affected by dengue fever are urged to take precautions against mosquito bites. If symptoms such as fever, headache, retroorbital pain, myalgia, arthralgia, and rash develop, 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, please visit the Taiwan CDC website at http://www.cdc.gov.tw or call the toll-free Communicable Disease Reporting and Consultation Hotline, 1922 (or 0800-001922).