On June 11, 2015, the Taiwan Centers for Disease Control (Taiwan CDC) announced this year’s first case of Japanese encephalitis in a 31-year-old housewife who resides in southern Taiwan. On June 2, she sought medical attention at a clinic after developing headache and fever. On June 4, when her symptoms persisted and she began to develop dizziness and vomiting, she sought medical attention at a hospital and was hospitalized in the intensive care unit. After the hospital reported her to the health authority as a suspected Japanese encephalitis case, infection was confirmed in the case on June 10. As of now, the case is still unconscious and hospitalized.

According to the epidemiological investigation, the case had not recently traveled overseas, but there are pig farms, pigeon farms and rice paddy fields within 2 km of the case’s residence. Hence, it is determined that the source of infection is somewhere around the case’s residence. Currently, none of the family members residing in the same household has experienced any symptoms. To prevent the further spread of the disease, the local health authorities has set up mosquito lamps around the residence of the confirmed cases as an attempt to capture vector mosquitoes, reinforced health education among residents who live near the confirmed cases as well as urged routine vaccination of age-appropriate children. As the Japanese encephalitis season has approached, Taiwan CDC urges the public to take precautions against mosquitoes and advises parents to have children vaccinated at local health bureaus and designated hospitals as soon as possible.

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 June 10, one Japanese encephalitis case has been confirmed in Taiwan. During 2010 and 2014, the total numbers of confirmed Japanese encephalitis cases respectively are 33, 22, 32, 16 and 18. People of all ages can become infected. People aged between 30 and 59 are at increased risk for infection. The surveillance data also shows that most cases are reported in central and southern Taiwan. 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 designated medical institution to prevent infection and severe complications.

The primary vector of Japanese encephalitis is a species of mosquito, Culex tritaeniorhynchus. 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).