On May 22, 2017, the Taiwan Centers for Disease Control (Taiwan CDC) announced this year’s first case of Japanese encephalitis in a 50-year-old male who resides in Kaohsiung City. On May 11, he sought medical attention at a hospital when he experienced weakness in limbs, fever and difficulty urinating. On May 16, when his conditions worsened and he developed consciousness change, he was transferred to a medical center for further treatment. On May 18, he was reported to the health authority as a suspected case. On May 22, infection with Japanese encephalitis was confirmed in the case, making the case this year’s first Japanese encephalitis case. As of now, the case has regained consciousness and is still hospitalized for treatment.

According to the epidemiological investigation, the case had not recently traveled overseas, had not been vaccinated against Japanese encephalitis, and spent most of his time at home (Hunei District, Kaohsiung City) and work area (Luzhu District, Kaohsiung City). There are 2 pig farms nearby the case’s work place. Hence, it was determined that he might have caught the infection around his work place. To prevent the further spread of the disease, the local health authority has set up mosquito lamps around the residence of the confirmed case and the places he frequents as an attempt to capture vector mosquitoes and reinforced health education among residents who live near the confirmed case as well as urged routine vaccination of age-appropriate children.

According to Taiwan CDC’s surveillance data, transmission of Japanese encephalitis in Taiwan occurs annually between May and October and it usually peaks between June and July. Thus far this year, as of May 22, 2017, 1 Japanese encephalitis case has been confirmed in Taiwan. During 2012 and 2016, the total numbers of confirmed Japanese encephalitis cases respectively are 32, 16, 18, 30 and 23.

As vaccination is the most effective way to prevent Japanese encephalitis, people who live near or work in close proximity to pig farms or rice paddy fields that increase their risk of Japanese encephalitis infection are recommended to visit one of the hospitals under the Ministry of Health and Welfare for self-paid vaccination. In addition, Taiwan CDC also urges parents and caretakers of age-appropriate children who have not received the vaccine to get vaccinated as soon as possible at their local health center or contracted healthcare facilities to prevent infection and severe complications.

The primary vector of Japanese encephalitis is a species of mosquito, Culex tritaeniorhynchus, which breeds in rice paddy fields, ponds, and irrigation canals. The vector mosquitoes are most active during dawn and dusk. Pigs act as the amplifying host for Japanese encephalitis. To prevent infection, avoid visiting vector-breeding sites such as pigpens at dawn and dusk when mosquitoes are most active. When needing to visit mosquito-prone places, people are advised to wear light-colored, long-sleeved shirts and long pants, and apply officially approved mosquito repellent to exposed body parts to prevent mosquito bites and lower the risk of contracting Japanese encephalitis. For any questions or further information, please visit the Taiwan CDC’s website at http://www.cdc.gov.tw or call the toll-free Communicable Disease Reporting and Care Hotline, 1922 (or 0800-001922).