The Korean Centers for Disease Control (KCDC), Chief of the General Affairs Division issued a Japanese encephalitis warning (computer translated) for the whole country Tuesday after confirmed the presence of the mosquito vector in Jeju.

South Korea

Health officials describe the mosquito to the public as small,dark brown with a wide white band at the center of the muzzle (about 4.5mm), also described as a small red house mosquito. They advise the public to take measure to prevent mosquito bites.

A Japanese encephalitis warning is issued when the Japanese encephalitis virus is isolated from the collected mosquito.

It is recommended that children between 12 months and 12 years old be vaccinated against Japanese encephalitis  according to the standard schedule.

Japanese encephalitis is the most important cause of viral encephalitis in Asia. About 68,000 clinical cases are reported annually. It usually occurs in rural or agricultural areas, often associated with rice farming.

The virus is transmitted to humans through the bite of infected Culex species mosquitoes, particularly Culex tritaeniorhynchus.

Most JE virus infections are mild (fever and headache) or without apparent symptoms, but approximately 1 in 250 infections results in severe disease characterized by rapid onset of high fever, headache, neck stiffness, disorientation, coma, seizures, spastic paralysis and death. The case-fatality rate can be as high as 30% among those with disease symptoms.

In 2016, South Korea reported 28 Japanese encephalitis cases, including 3 deaths.