The World Organisation for Animal Health (WOAH), on its commitment to maintain international standards current with the newest scientific developments, is updating its Terrestrial Animal Health Code (Terrestrial Code) chapters on equine encephalitides. These updates seek to improve both animal and public health worldwide. The revised chapters will aim at providing an up-to-date reference to WOAH Members on disease surveillance, to facilitate the safe international trade of animals and their products with regards to Eastern (EEE) and Western equine encephalomyelitis (WEE), Japanese Encephalitis (JE), Venezuelan equine encephalomyelitis (VEE) and West Nile Fever and will advocate for a One Health approach to effectively address zoonotic risks  and protect public health. 

Following the Terrestrial Animal Health Standards Commission decision to update four Terrestrial Code chapters on equine encephalitides (EEE, WEE, JE and VEE), an ad hoc Group of experts on horse diseases convened at WOAH Headquarters last June to first revise Terrestrial Code Chapter 12.4. on Eastern and Western equine encephalomyelitis. The ad hoc Group was tasked to review the latest scientific developments and the recently updated Terrestrial Manual Chapters, to follow the recommendations of the recent listing assessment undertaken by the Scientific Commission for Animal Diseases, and to consider requests from Members and partners, such as the International Horse Sports Confederation, to address the recent crisis related to these diseases.   

Over the three-day meeting, five experts and two representatives from the WOAH Specialist Commissions, assisted by the WOAH Secretariat, drafted a revised Chapter 12.4. The Group highlighted the public health hazards of these zoonotic diseases. The Group also recommended that neither disease should hinder the international transit of horses, regardless of the animal health status of their country or zone of origin, as horses are dead-end hosts. 

Review of Japanese encephalitis and Venezuelan equine encephalomyelitis

The Group also undertook an initial revision of the Terrestrial Code chapters on Japanese encephalitis and Venezuelan equine encephalomyelitis and identified unique features of each disease that warrant them to be listed in separate chapters. This focused approach will ensure that their distinct characteristics are appropriately addressed. New ad hoc Groups will be convened to update these chapters, but consistency across all four diseases will be sought. The work will also include consideration of consistency with the Terrestrial Code Chapter on West Nile Fever.  

The report of the ad hoc Group will be reviewed by the Terrestrial Animal Health Standards Commission and the Scientific Commission for Animal Diseases during their September 2024 meetings. 

More information: 

Chapter 12.4. Equine encephalomyelitis (Eastern and Western) 

Chapter 8.10. Japanese encephalitis  

Chapter 12.11. Venezuelan equine encephalomyelitis 

Contact: WOAH Standards Department (standards.dept@woah.org) 

Main photo: WOAH equine disease experts and secretariat © WOAH and Horse transport ©Unsplash/S. Busby