On July 26, 2019, the Taiwan Centers for Disease Control (Taiwan CDC) announced this year’s first indigenous Chikungunya case confirmed in an over 20-year-old female who resides in Yongning Village, Tucheng District, New Taipei City. She had not recently traveled overseas and her primary areas of daily activities included her residence and Pitang Village, Tucheng District. Since July 21, the case subsequently developed symptoms, including fever, joint pain, headache, and rash. On the following day when she sought medical attention for the second time, she was reported to the competent health authority as a suspected dengue fever case and as a suspected measles case when her specimens were collected for laboratory testing. Laboratory testing had eliminated infection with both dengue fever and measles in the case. However, the case was tested positive for Chikungunya. As of now, the case’s symptoms have improved and the case is being isolated at home. None of her contacts have developed suspected symptoms.
According to the epidemiological investigation, the areas surrounding the case’s residence and her areas of daily activities were places frequented by foreign workers. The case claimed that she was bitten by mosquitoes when visiting Pitang Village. The source of her infection is still being investigated. To prevent the further spread of the disease, the local health authority has implemented a number of prevention and control efforts since July 23, including conducting epidemiological investigation such as risk assessment and mosquito density survey around the areas where the case frequented, eliminating vector breeding grounds around the same areas through cleaning vector breeding sites and spraying insecticide, as well as reinforcing health education among residents in the areas.
Thus far this year, a cumulative total of 17 Chikungunya cases, including 1 indigenous dengue case and 16 imported cases, have been confirmed in Taiwan. Among the imported cases, 6 were from Myanmar, 4 from the Maldives, 2 from Indonesia, and 1 each from Thailand, the Philippines, Malaysia and Indonesia.Since Chikungunya was listed as a notifiable infectious disease in Taiwan beginning October 2007, the cumulative number of cases confirmed thus far this year has been the highest during the same period in the past years.Taiwan CDC pointed out that both Chikungunya and dengue fever are transmitted by the bites of infected Aedes aegypti and Aedes albopictus mosquitos. The incubation period varies from 2 to 12 days. Infected individuals are viremic from 2 days prior to symptom onset untill 5 days after symptom onset. The symptoms of Chikungunya are similar to those of dengue fever, including sudden onset of fever, joint pain, headache, nausea, fatigue, and muscle ache. About half of the cases develop rash. Most patients can recover within 1 week.
According to the international surveillance data, Chikungunya is currently circulating in a neighboring country, Thailand, and the virus activity in the country has been on the rise with a cumulative total of 5,200 cases confirmed thus far this year. Further, so far this year, a cumulative total of over 1,300 cases have been confirmed in the Maldives, 289 cases have been confirmed in Malaysia, and 25 cases have been confirmed in Singapore. In the Americas, a cumulative total of 66,000 probable cases have been confirmed in Brazil. In Africa, a cumulative total of over 11,000 cases have been confirmed in the Democratic Republic of the Congo. All of the aforementioned countries have reported a higher number of cases compared to the same period last year. On the other hand, a cumulative total of over 14,400 cases have been confirmed in India thus far this year.
Taiwan CDC urges, regardless of Chikungunya or dengue fever, the most effective way to prevent infection with these diseases is to remove vector breeding sites. Hence, the public is advised to regularly patrol their living environment and thoroughly empty and clean any potential vector breeding sites such as containers that collect standing water in and around the home in order to prevent vector mosquitoes from breeding. Further, travelers visiting Chikungunya-affected areas are urged to take precautions against mosquito bites such as wearing light-colored clothing, long sleeves and long pants, applying government agency-approved mosquito repellent to exposed parts of the body, and staying at accommodations installed with window screens and screen doors. If suspected symptoms develop, please seek immediate medical attention and inform the doctor of any recent travel and activity history to facilitate prompt diagnosis, case reporting, and treatment. For more information, please visit the Taiwan CDC’s website at https://www.cdc.gov.tw or call the toll-free Communicable Disease Reporting and Consultation Hotline, 1922 (or 0800-001922).