African Horse Sickness
African Horse Sickness
African Horse Sickness is a highly fatal and infectious disease, which affects horses, mules, donkeys and zebras.
African Horse Sickness Questions and Answers
What is African Horse Sickness?
African Horse Sickness is a highly fatal and infectious disease, which affects horses, mules, donkeys and zebras. The spread of the disease is similar to Bluetongue, in that it is not directly contagious between horses as it is influenced by climatic conditions which favour the spread of carrier insects. It is known to be endemic in Sub-Saharan Africa, and has spread to Morocco, the Middle East, India and Pakistan. More recently, outbreaks have been reported in the Iberian Peninsula. Dogs can also be severely infected by the virus, usually by eating infected horsemeat.
What are the clinical signs?
The clinical signs seen are different depending on what form of the disease is present.
- Affected horses have a high fever, severely laboured breathing, coughing and profuse discharge from the nostrils. The mortality rate is very high with up to 95% of horses dying within a week.
- In the cardiac form of the disease, which has an incubation period of from seven to fourteen days, swellings are present over the head and eyelids, lips, cheeks and under the jaw. The mortality rate is around 60 per cent and death results from heart failure.
- The mixed form of the disease is a combination of the above two types. It has an incubation period of from five to seven days and the disease shows itself initially by mild respiratory signs followed by the typical swellings of the cardiac form.
- Horse sickness fever is the mildest form, characterised by a fever with low temperatures in the morning rising to a high peak in the afternoon.
How is the disease transmitted?
The spread of disease is influenced by climatic conditions which favour the spread of carrier insects (vectors) including warm, moist weather and high rainfall, as well as spread by wind dispersal. It is likely that the virus persists (overwinters) in other, unknown species in Africa when the insect is not active. This explains why the disease does not persist in other countries following an outbreak.
Is there a vaccine available?
On 18 December 2008 the EU Commission published its decision (2009/3/EC) to make arrangements for the purchase of 100,000 doses of monovalent attenuated live vaccine against African Horse Sickness of each of the serotypes 1, 2, 3, 4, 6, 7 and 8. The contract for 2009-10 will be with Onderstepoort Biological Products Ltd (OBP) in South Africa for the supply, storage and delivery of the vaccines. The arrangements shall include the supply and storage of the vaccines and the shipment of the specified vaccines to the European Union, or epidemiologically relevant direct neighbours, designated in case of emergency by the Commission.
No vaccine for AHS is currently licensed in the EU. Use of a modified live vaccine for AHS (such as the one being produced by OBP) carries a risk of vaccine virus reversion to wild type (i.e. the virus used in the vaccine can potentially undergo changes that mean it could actually infect vectors, and subsequently susceptible equidae). Thus at the present time, the vaccine will not be considered for use in the UK other than in an emergency situation.
What legislation currently exists?
African Horse Sickness is included in The Specified Diseases (Notification) Order (Northern Ireland) 2004.
Imported horses from at-risk countries outside the European Union are routinely tested for African Horse Sickness. The severity of disease could significantly affect the Equine Industry in the United Kingdom, particularly in southern UK, where this disease is most likely to occur.
DARD ADVISES THAT YOU DO NOT IMPORT HORSES FROM ANY TERRITORY OR TAKE HORSES TO COMPETE IN ANY TERRITORY IN WHICH AFRICAN HORSE SICKNESS IS PRESENT OR WHICH VACCINATES AGAINST AFRICAN HORSE SICKNESS.
If you suspect the presence of the disease, contact your local Divisional Veterinary Office immediately. To find the telephone number of your nearest office, call the DARD helpline on: 02890 524999, or visit the
DARD websiteRelated Links
