On June 23, 2016, the Taiwan Centers for Disease Control (Taiwan CDC) announced a new Japanese encephalitis case in Nantou County, which is the first case confirmed in the County this year. The case is a 62-year-old male who has retired.　On June 11, he developed symptoms such as fever, diarrhea, nausea and loss of appetite. On June 13, he sought medical attention at a hospital and was hospitalized for treatment. On June 16, he was transferred to another hospital for further treatment after he developed unconsciousness. After the hospital reported him to the local health authority as a suspected Japanese encephalitis case, infection was confirmed in the case by the Taiwan CDC laboratory on June 23. As of now, the case is conscious and hospitalized for treatment.

According to the epidemiological investigation, the case’s primary areas of daily activities are places around his residence. In addition, there are no pig farms or pigeon farms within 2 km of the case’s residence. However, the case visited an outdoor recreation park during incubation period and there is a rice paddy field and one pigeon farm within 1-2 km of the park. Hence, it is determined that the source of infection is somewhere around the park. 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 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 June 23, 4 Japanese encephalitis cases have been confirmed in Taiwan, including 2 in Kaohsiung City, 1 in Tainan City, and 1 in Nantou County. During 2010 and 2015, the total numbers of confirmed Japanese encephalitis cases respectively are 33, 22, 32, 16, 18 and 30. People of all ages can become infected. People aged between 30 and 59 are at increased risk for infection.

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 healthcare institution to prevent infection and severe complications.

The primary vector of Japanese encephalitis in Taiwan is a species of mosquito, Culex tritaeniorhynchus. They often breed in rice paddy fields, ponds and trenches. 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).