On June 18, 2015, the Taiwan Centers for Disease Control (Taiwan CDC) announced two new Japanese encephalitis cases and they respective are a 42-year-old and a 58-year-old males. According to the epidemiological investigation, the cases had not recently traveled overseas, but there are pig farms, pigeon farms and rice paddy fields within 2 km of the cases’ residences. 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 households 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.

On June 4, the 42-year-old case sought medical attention after developing sore throat and mild cough. On the following day, his symptoms improved. However, on June 6, he developed lethargy. In the early morning of June 7, when he developed fever and unconsciousness, he was transferred to the intensive care unit. On the other hand, the 58-year-old case developed runny nose on June 6. In the evening of the next day, he developed fever. In the afternoon and evening of June 8, he sought medical attention at a clinic and a hospital. On June 9, when his fever persisted and he developed unconsciousness, he was hospitalized in the intensive care unit. Both cases were reported to the health authority by their hospital as a suspected Japanese encephalitis case. Infection with Japanese encephalitis was later confirmed in both cases. As of now, both cases are still hospitalized.

According to Taiwan CDC’s surveillance data, thus far this year, as of June 18, a total of three Japanese encephalitis cases have been confirmed and all of them occurred in southern Taiwan. Transmission of Japanese encephalitis in Taiwan occurs annually between May and October and it usually peaks between June and July. As severe cases may experience psychological or neurological sequelae, and even death, Taiwan CDC advises the public to take all the necessary precautions to prevent infection. Parents are urged to make sure their children receive the vaccine timely. 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, that 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).