Epizootic Haemorrhagic Disease

Epizootic Haemorrhagic Disease (EHD) is a vector-borne infectious non-contagious viral disease of domestic and wild ruminants. EHD is caused by the Epizootic Haemorrhagic Disease Virus (EHDV). Currently EHD is not present in Ireland, however significant circulation of EHDV across Europe increases the risk of spread to Ireland. A potential outbreak would have a significant negative impact on animal welfare and trade within the livestock sector. The disease can cause serious illness and death in some affected animals.

The disease does not pose a risk to humans or to food safety.

EHD is a notifiable disease, meaning that any suspected cases must be reported to the Department of Agriculture, Food and the Marine without delay. There is currently no vaccine against EHD available in the European Union.

Epizootic Haemorrhagic Disease virus (EHDV) causes disease in domestic and wild ruminants.

It primarily affects white-tailed deer and cattle. Sheep, goats and camelids might also be susceptible, but usually do not develop overt disease.

Epizootic Haemorrhagic Disease virus (EHDV) is transmitted between ruminants by infected biting midges (Culicoides species), many of which are found throughout the island of Ireland.

Transmission of the virus occurs primarily when midges feed off the blood of an infected animal and then spread the virus to subsequent animals they bite. The higher-risk period for disease spread is when midges are most active, which in Ireland is usually between April and November. Milder winters can result in the midges that are responsible for spreading disease remaining active for longer periods.

Wind speed and direction can also affect how far midges can travel and could potentially facilitate the spread of the disease if it were to occur in Ireland.

Ireland and the UK are currently free from Epizootic Haemorrhagic Disease (EHD). EHD was reported for the first time in Europe, in Sardinia, Italy in November 2022. Since then, the disease has been confirmed in Sicily, Spain and Portugal. In September 2023, EHD was confirmed in France initially in the Hautes-Pyrénées and Pyrénées-Atlantiques region, close to the Spanish border.

The recent spread of EHDV in Europe is significant for Ireland, as it has increased the potential for spread across mainland Europe, towards the UK and Ireland.

A map and table detailing all the Epizootic Haemorrhagic Disease restricted territories in the EU are available here: Epizootic haemorrhagic disease (europa.eu)

Epizootic Haemorrhagic Disease virus (EHDV) belongs to the same viral family (Reoviridae) as Bluetongue virus (BTV), and hence shares many morphological and structural characteristics, leading to clinically similar diseases. No cross-protection exists between EHDV and BTV.

Within livestock species, cattle are most affected. Sheep and goats can also be infected but rarely show noticeable clinical signs. Mortality among farm animals is generally low.

Due to the clinical presentation, Bluetongue is a key differential diagnosis, along with Foot and Mouth Disease (FMD) in deer and cattle. Clinical signs of EHD are indistinguishable from those of Bluetongue. Additional differential diagnoses in cattle are bovine viral diarrhoea (BVD), infectious bovine rhinotracheitis (IBR), vesicular stomatitis, malignant catarrhal fever (MCF), and bovine ephemeral fever.

There are a wide range of clinical signs of Epizootic Haemorrhagic Disease to look out for including:

• Fever

• Anorexia, inappetance

• Lesions on the muzzle and lips

• Swelling of the head and neck

• Drop in milk yield

• Reddening of the mucus membranes

• Sores on the nose, gums and dental pads

• Respiratory distress

• Drooling, Dysphagia (difficulty swallowing)

• Discharge from the eyes and/or nose

• Lameness

• Abortion or deformities in offspring

• Haemorrhages in many tissues including the skin and heart

• Possible death (in severe cases)

Images of some of the more obvious clinical signs of Epizootic Haemorrhagic Disease can be viewed here:

If you have any concern that one of your animals has Epizootic Haemorrhagic Disease, do not delay in taking action. Isolate the suspect animal(s) indoors immediately and report the case to the Department of Agriculture Food and the Marine.

To report a suspect case, please contact your local Item was unpublished or removed (9am-5pm). Outside of office hours, you can ring the National Disease Emergency Hotline on 01-492-8026 (which is operational 365 days of the year).

An Epizootic Haemorrhagic Disease (EHD) outbreak in Ireland would have immediate trade implications, with difficulties in exports to 3rd countries.

In the event of an outbreak of EHD occurring in Ireland control measures would have to be introduced to try and eradicate the disease. There is currently no vaccine authorised for use in the European Union for EHD. Other control measure to reduce disease spread could also be implemented by DAFM.

There are 2 main ways that Epizootic Haemorrhagic Disease could enter the country:

• Import of infected live animals.

• Weather conditions allowing for infected midges to be carried on the wind to Ireland from countries affected with Epizootic Haemorrhagic Disease.

The greatest threat to Epizootic Haemorrhagic Disease entering the country comes from the import of an infected animal from a country in which Epizootic Haemorrhagic Disease is currently circulating. Therefore, anyone intending to import an animal from mainland Europe should ask themselves the following questions before doing so:

• Is import of these animals necessary?

It is possible that the breed changes or genetic gain that you are seeking for your animals can be obtained locally or from an Epizootic Haemorrhagic Disease -free country such as the UK. Avoid importing animals that could compromise the health of your own and the national herds/flocks, as a matter of priority.

Ensure the animals are EHD virus-free before they leave the exporting country by requesting a pre-export PCR test for the virus.

• If the import is necessary, when should it occur?

Every effort should be made to only import susceptible animals from December-March inclusive, which is outside of the midge’s most active time of year. This will help to reduce the risk of midges spreading the virus if it should enter the country, but it will not eliminate it completely. With milder temperatures in general, midges can be active in Ireland almost year-round.

The Department of Agriculture, Food and the Marine has published specific biosecurity advice for livestock farmers who are planning to import animals (see below).

• Am I buying these animals from a reputable source?

Always consult with your Private Veterinary Practitioner before purchasing animals from another country for advice on pre-import tests and health status requirements to ensure that they do not bring disease into your herd, flock or the country. Always purchase animals from reputable sources and ensure pre-export test results for any relevant diseases such as Epizootic Haemorrhagic Disease before you import.

Contact your local Regional Veterinary Office (RVO) for information on import requirements such as Intra-EU Health Certificates, and ensure that have you have adequate facilities for isolating the animals indoors away from the rest of the herd or flock.

• What do I do when the animals arrive on my farm?

The Biosecurity for Livestock Farmers Importing Animals leaflet contains detailed advice (see below), of which the following are some first steps:

a) Check that the correct documents accompanied the animals (identification cards, Intra-EU Health Certificates etc).

b) Check that animals appear healthy and have access to clean dry bedding, clean water and food. If any animals appear unwell contact your Private Veterinary Practitioner without delay.

c) Ensure all imported animals from mainland Europe are visited by an RVO vet within 5 days of arrival into Ireland. Inform your local Regional Veterinary Office (RVO) as soon as the animals arrive onto your premises to arrange a post-import visit. Keep animals isolated and housed on your farm until the RVO is satisfied that they do not present a risk of spreading Epizootic Haemorrhagic Disease.

d.) Isolate imported animals indoors as soon as they arrive onto your holding and monitor them closely for any signs of illness. Biosecurity advice for farmers importing livestock can be found here.

Epizootic haemorrhagic disease - WOAH - World Organisation for Animal Health

animal-diseases.efsa.europa.eu/EHDV

Epizootic Haemorrhagic Disease Updates