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One Health: French farmers facing the Epizootic Haemorrhagic Disease (EHD)
Dr Hajar Boutayeur Technical Officer Veterinary Public Health Center
Dr Guillaume Convert VPH Technical Service Director Veterinary Public Health Center Boehringer Ingelheim Animal Health
Dr Albert Picado de Puig Principal Scientist Animal Health Global innovation
Emergence of Epizootic Hemorrhagic Disease in Europe: A One Health Challenge Epizootic Hemorrhagic Disease (EHD) is a vector- borne, viral illness impacting both domestic and wild ruminants. Recognized as a notifiable disease by the World Organisation for Animal Health (WOAH) since 2008, EHD virus (EHDV) belongs to the Reoviridae family, genus Orbivirus, sharing structural similarities with Blue Tongue Virus (BTV), African Horse Sickness (AHS) and Equine Encephalosis Virus (EEV).
vectors are found. Previously, the disease was known to be transmitted by tropical midges like Culicoides imicola, but transmission patterns have likely shifted due to environmental changes such as global warming. In Europe, EHD has been detected in regions where other vectors, such as C. obsoletus and C. scoticus , are present. This indicates a change in vector competence, suggesting that Northern European Culicoides species can now transmit the disease. EHDV serotype 8 (EHDV-8), initially confined to Australia until detected in Tunisia in 2021, was reported in Europe for the first time in 2022 with outbreaks in Sardinia, Sicily, Spain and Portugal. In France, the first EHD outbreaks were reported in September 2023 on cattle farms in the southwest. This has since escalated into a major veterinary and agricultural challenge, with more than 4000 outbreaks recorded across 20 departments as of July 2024. Control measures are enforced within a 150 km radius of detected outbreaks.
First identified in the USA in 1955, EHD has since spread globally, with at least seven known serotypes. While the disease was mostly pathogenic in wild ruminants in the USA, outbreaks of other EHDV variants/serotypes reported in Asia (EHDV serotype 2 in Japan known as the Ibaraki disease), in the middle east (EHDV serotype7 in Israel, EHDV serotype 6 in Turkey and Oman) and in north of Africa (EHDV serotype 6 in Tunisia, Morocco, Algeria) were associated with clinical signs in domestic cattle. EHD is transmitted by adult female species of Culicoides biting midges, meaning its spread is inherently restricted to areas where these competent
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