Veterinary Researchers at AFBI have issued advice to farmers to help them protect their cattle from the effects of the viral disease, Malignant Catarrhal Fever (MCF).
MCF is a severe, usually fatal disease of cattle. The disease in the UK is caused by a virus called Ovine Herpesvirus-2, which is carried by sheep without causing clinical disease in this species. There is no specific treatment, and the disease is fatal in almost all animals that show clinical signs.
There is no vaccine available, and prevention relies on not co-grazing sheep and cattle, and in particular not housing cattle together with pregnant, lambing or recently lambed sheep.
The virus is transmitted from sheep to cattle, the exact mechanism by which this occurs is unknown, during periods of close contact, most frequently by pregnant or recently lambed sheep (or goats), and also by neonatal lambs. Sheep are lifelong carriers, and shedding of the virus may be increased during periods of stress, such as transport, housing etc.
Signs of clinical disease in cattle may not appear for several months after contact with sheep occurs, and the disease does not spread easily between individual cattle; only very rare cases of cattle to cattle transmission have been reported. AFBI diagnoses a number of cases each year, usually these are sporadic cases with single animals affected, but occasionally outbreaks occur, with multiple animals from the same group affected.
Clinical signs reflect the severe disease that affects multiple organ systems, including respiratory, gastrointestinal, neurological and skin. Animals may be found dead, but clinical signs include profound depression; a high temperature (40.5-42 C); inappetence; blindness due to corneal opacity; a clear discharge from the eyes and nose which becomes thick and yellow (mucopurulent); crusting and ulceration of the mucous membranes and skin (including the muzzle and in the mouth and nose, around the coronary band and udder); enlargement of all of the lymph nodes; and neurological signs which may include seizures. Death occurs within 5-10 days of the onset of clinical signs. Some of the clinical signs are similar to those seen in other diseases such as BVD- Mucosal Disease, severe IBR, listerial iritis (silage eye) and Bluetongue.
Diagnosis of Malignant Catarrhal Fever may be suspected on clinical signs, and is confirmed by identification of the virus in blood or tissue samples, or antibody to the virus in blood samples, as well as by characteristic findings at post mortem examination.
Testing of blood samples from suspected clinical cases is available at AFBI, but full post-mortem examination is advised in cases where deaths occur.
AFBI Lab contact details:
- Phone: +44 (0) 2890 525 649
- Email: DSIBSample.Enquiries@afbini.gov.uk
Notes to editors:
AFBI is an arms-length body of DAERA delivering research and development, diagnostic and analytical testing, emergency response capability and expert scientific advice for DAERA and other government departments, public bodies and commercial companies in Northern Ireland, and further afield.
AFBI’s Vision is “Advancing the Local and Global Agri-Food Sectors Through Scientific Excellence”.
AFBI’s core areas:
- Leading improvements in the agri-food industry;
- Protecting animal, plant and human health;
- Enhancing the natural and marine environment.
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