Japanese encephalitis in South Korea

The Korea Disease Control and Prevention Agency (KDCA) issued a nationwide Japanese encephalitis alert on July 25 2024. A recent study in the Gyeongnam and Jeollanam areas found most mosquitoes were infected with japanese encephalitis virus. No human cases have been reported at this time.

Japanese encephalitis virus (JEV) is a mosquito-borne virus which affects the central nervous system. It is most common around areas of rice and pig farming. JEV is transmitted from animals (mainly pigs/birds) to humans through the bite of an infected Culex mosquito which feeds in the hours around dusk. No human-to human transmission occurs.

Advice for Travellers

All travellers to endemic countries or outbreak areas are potentially at risk of infection. This risk is greatest for those:

• travelling to rural areas during transmission seasons
• participating in outdoor activities during twilight hours
• travelling for a prolonged period of time

All travellers should be advised on:

• the risks and potentially severe consequences of Japanese encephalitis
• practicing strict mosquito bite avoidance measures, including correct use of insect repellents
• minimising outdoor activities during twilight hours when Culex mosquitoes bite

Travellers at increased risk of developing severe clinical disease are those:

• with pre-existing chronic medical conditions
• younger than 10 years of age
• older than 50 years of age

When to consider vaccination

For most travellers the risk of acquiring infection will be very small, but consider vaccinating those:

• frequently exposed to bites in rural infected areas (e.g. backpackers, agricultural workers, volunteers)
• at ongoing risk or repeatedly visiting 'high risk' areas (e.g. flood plains, rice paddies, marshlands, pig farms)
• staying for short periods during epidemics/outbreaks
• staying for long periods (e.g. more than one month) in infected areas
• going to live in an endemic area

For further information, see the Japanese Encephalitis page.