News

Epizootic Haemorrhagic Disease: Evolution and Current Situation

Epizootic Haemorrhagic Disease (EHD) is a disease that affects domestic and wild ruminants. The virus was initially identified in North America in 1955 in a white-tailed deer, causing severe clinical signs and high mortality rates. Meanwhile, in its impact on domestic ruminants like cattle, sheep, goats, and camelids, the clinical presentation tends to be milder, albeit variable. However, recent expansions of EHD into new regions raise concerns within the livestock industry due to the potential economic losses it can cause.

The agent that causes EHD is the Epizootic Haemorrhagic Disease Virus (EHDV), which has been classified into 8 serotypes, ranging from EHDV-1 to EHDV-8, although some researchers propose the existence of two additional serotypes. The virus is indirectly transmitted by a small biting midge close to a mosquito and direct transmission between ruminants is not possible.

Epizootic Haemorrhagic Disease History

As we mentioned before, the disease was documented for the first time in 1955 in the USA in white-tailed deer. Since then, it has been identified in Canada, Mexico, and other various global regions including Africa, South America, Middle East, Southeast Asia, Japan and Australia. 

Nevertheless, in October and November 2022, some outbreaks occurred nearly simultaneously in southern Europe, affecting Sicily, Sardinia, and Andalusia in southern Spain. These outbreaks were attributed to serotype 8, a strain initially observed in Australia in 1982 and later reemerging in Tunisia in 2021.

After the initial wave, the disease’s spread halted on December 1, 2022, coinciding with decreased vector activity. Nevertheless, from June 2023, new outbreaks began appearing further north and east in Spain, extending to Portugal and approaching the French border, while Italy remained confined to Sicily and Sardinia.

How is EHD transmitted?

EHD cannot be directly transmitted from one animal to another and experts suspect that the disease spreads naturally through wind transported infected insects. This hypothesis aligns with the serotype 8 found in Spain and Italy, mirroring the strain circulating in Tunisia since 2021. 

Infections peak during periods of heightened insect activity, most notably in late summer and autumn. As winters become milder, the insect’s activity may extend into the colder months, potentially leading to cases emerging during winter or spring. Furthermore, climate-related factors may influence the geographic spread of the disease. 

Control and treatment for EHD

Ceva is always working on new ways and products to ease the path for our community of veterinarians and farmers, so to support our customers and authorities in the fight against this devastating disease, Ceva has partnered with CZ Vaccines to make a vaccine available to veterinarians and farmers.

Hepizovac not only reduces clinical signs of the disease but is also the first vaccine to demonstrate prevention of viremia in cattle, which is essential to control the disease by limiting the transmission of the infected animals to vectors. This vaccine is a key tool to protect cattle under our care.

Predictions for the future in Europe

Historical data on EHD progression, vector activity, and climate suggests that the outbreaks will dramatically increase with the warm weather arrival in the spring of 2025, when the insects are most active. Several European countries have put in place vaccination strategies to ensure that the animals are vaccinated and protected before the risk season arrives.

To stay to date with the latest actualizations on the ruminants world, visit News and Events section, and follow us in our social media.