What is Japanese encephalitis?
Japanese encephalitis (JE) is a mosquito-borne disease characterized by inflammation (swelling) of the brain. Most JE infections are mild (fever and headache) or without apparent symptoms. In severe cases, symptoms include rapid onset of high fever, headache, neck stiffness, disorientation, and sometimes seizures, paralysis and coma. There is no specific treatment. Severe illnesses are treated by supportive therapy to relieve symptoms and stabilize the patient. JE is fatal in up to 30% of cases. Among survivors, up to 30-50% have long-term neurologic sequelae. Safe and effective JE vaccines are available to prevent disease.
Japanese encephalitis in the region
Japanese encephalitis (JE) virus is transmitted to humans through bites from infected mosquitoes in a cycle with water birds and sometimes pigs. JE virus transmission occurs across broad areas of South East Asia and the Western Pacific, including parts of 24 countries: Australia, Bangladesh, Bhutan, Brunei Darussalam, Cambodia, China, Democratic People’s Republic of Korea, India, Indonesia, Japan, Lao People’s Democratic Republic, Malaysia, Myanmar, Nepal, Pakistan, Papua New Guinea, Philippines, Republic of Korea, Russian Federation, Singapore, Sri Lanka, Thailand, Timor-Leste, and Viet Nam. JE usually occurs in rural or agricultural areas, often associated with rice farming. In temperate areas of Asia, transmission is seasonal, and human disease usually peaks in the summer and fall. In the subtropics and tropics, transmission can occur year-round, often with a peak during the rainy season.
Accelerated control of JE in the Western Pacific
The Expert Consultation on Accelerated Control of Japanese Encephalitis in the Western Pacific Region was held on 14–16 March 2016 in Manila, Philippines. The Consultation was attended by 10 participants from 10 countries, 2 temporary advisers, 5 representatives from 4 partner organizations, and 6 World Health Organization (WHO) staff members from the Regional Office for South-East Asia, Regional Office for the Western Pacific and Philippines Country Office. The participants discussed the burden of Japanese encephalitis (JE), surveillance for JE and acute encephalitis syndrome, progress towards controlling JE in the Western Pacific Region, and challenges, issues and lessons learnt by countries. Participants discussed accelerated control of JE, which was one of eight immunization goals included in the Regional Framework for Implementation of the Global Vaccine Action Plan in the Western Pacific. Participants reviewed recent literature on the incidence of JE, impact of JE vaccination, and surveillance and epidemiology of JE globally and in the Western Pacific Region. Participants discussed in detail the proposed targets and strategies for accelerated control of JE in the Region.