Epizootic haemorrhagic disease is a notifiable animal disease. If you suspect it you must report it immediately.

Outbreaks of EHD in cattle were reported for the first time in southern Europe in November 2022. It is not currently present in the UK.

EHD is caused by a virus of the family Reoviridae, genus Orbivirus, of which there are 8 or more serotypes. EHD demonstrates immunological cross reactivity with the Bluetongue virus group. Morbidity and mortality may be as high as 90% (especially in species such as in white tailed deer) however, severity varies depending on the year and geographical location.

EHD can affect:  Cattle, Sheep, Deer, Goats and other ruminants.

True persistent infection of ruminants does not occur. Sheep can be infected experimentally but rarely develop clinical signs, and goats do not seem to be susceptible to infection.

Symptoms

The incubation period for EHD is estimated at 2–10 days. 

In some cases, there are no obvious clinical signs that an animal is infected.

You are only likely to see signs of EHD in severe infections. 

The main signs of EHD are:

·        Fever

·        Weakness

·        Lack of appetite

·        Excess salivation

·        Difficulty swallowing

·        Skin rash on the udder

·        Bleeding (skin and internal tissues)

·        Swollen red skin near hooves

·        Swollen lining of the mouth

·        Mouth ulcers

·        difficulty breathing

·        Abortions and stillbirths have also been reported in some epidemics. Some affected cattle die (up to 10%)

·        Sudden death (particularly in deer)

·         

Acute outbreaks in cattle (similar to Bluetongue):

o   Fever

o   Anorexia

o   Reduced milk yield

o   Swollen conjunctivae

o   Redness and scaling of the nose and lips

o   Nasal and ocular discharge

o   Salivation

o   Stomatitis

o   Lameness

o   Swelling of the tongue

o   Oral/nasal erosions

o   In prolonged cases, oral ulcers on the dental pad, hard palate, and tongue may occur. Excessive bleeding occurs in fulminant disease: bloody diarrhoea, haematuria, dehydration, and death.

How EHD is spread

EHD virus is transmitted by midge vectors, usually biting midges of the genus Culicoides, after an external extrinsic period of 10–14 days. In temperate regions infection is most common in the late summer and autumn during peak vector population, while infection occurs throughout the year in tropical regions.

EHD could spread to the UK if infected midges are carried by the wind. The risk of this happening depends on:

·        Whether disease spreads to animals in nearby areas of Europe

·        The presence of infected midges in nearby areas of Europe

·        Weather patterns

EHD could also spread to the UK if infected live animals, or their germinal products, are imported from countries where EHD is circulating.

This includes:

·        Blood of viraemic animals (Infection in ruminants is not contagious – biological vectors (Culicoides sp.) are required.

·        Infected endothelium, (all tissues of the body may be affected.)

 

As in Bluetongue infection, viraemia can be prolonged beyond 50 days, despite the presence of neutralising antibody, due to an intimate association between virus and erythrocytes. Infected deer can be viraemic for up to 60 days.

 

Preventing and controlling EHD

There is no commercially available vaccine to protect against EHD.

You can help prevent EHD by practising strict biosecurity on your premises.

If EHD is confirmed, the outbreak will be controlled in line with the contingency plan for exotic notifiable diseases.

 

If a notifiable animal disease is confirmed

APHA will carry out further investigations at your premises to assess:

·        how long the disease has been present

·        where the disease came from

·        whether it has spread

APHA will put restrictions on any premises the disease is likely to have spread from or to (for example when animals have been moved). They may also introduce restrictions in a wider area, depending on the risk of the disease spreading. These are called disease control zones.

APHA may:

·        cull susceptible animals

·        carry out initial cleansing and disinfection of your premises

·        introduce strict rules on restocking

·        limit activities that could spread disease, such as exports, hunting and animal gatherings (such as fairs, markets, shows, sales, exhibitions and some premises used for dealing or internet sales).

 

Full details of what happens in the case of a notifiable disease outbreak can be found here  (https://www.gov.uk/guidance/what-happens-when-you-report-a-notifiable-disease-in-your-animals )