Japanese Encephalitis
Japanese Encephalitis is a mosquito-borne viral encephalitis caused by a flavivirus which occurs in widely dispersed areas in eastern Asia, including Papua New Guinea and Indonesia. It affects horses, pigs, birds and other species including humans. Birds act as a reservoir for infection.
If notifiable disease is suspected, contact DAERA on 0300 200 7840 or your local DAERA Direct Regional Office. Failure to do so is an offence
Current Situation
There has never been an outbreak of Japanese Encephalitis in Northern Ireland.
Clinical Signs
Three types of manifestations of Japanese Encephalitis can occur-transitory, lethargic, or hyperexcitable. Clinical signs, if present, vary; disease usually presents itself in sporadic or localized clusters.
How is the disease transmitted?
The virus is transmitted to horses through biting insects. One of the main mosquito vectors is Culex annulirostris in Queensland, Australia.
Prevention
You can help prevent Japanese Encephalitis by practising good biosecurity on your premises.
Single Lifetime Identification Document for Equines (“Horse Passports”)
All equines in Northern Ireland need to have a Single Lifetime Identification Document (commonly referred to as a “horse passport”) to identify them.
Further information on how to obtain a horse passport.
More useful links
Japanese encephalitis: the green book, chapter 20 - GOV.UK
https://horsedvm.com/disease/equine-japanese-encephalitis
Horse Illnesses: Equine Disease Prevention | The British Horse Society
International-Codes-of-Practice-2025_ITBA.pdf
HBLB International Codes of Practice | Home
Japanese encephalitis - WOAH - World Organisation for Animal Health