Possible Outbreak of African Horse Sickness

Since 16 March 2007 a total of 10 horses have died on properties located within the African horse sickness (AHS) Surveillance Zone. All these deaths were investigated by the Veterinary Authorities with post mortem examinations either conducted on-farm or at the Provincial Veterinary Laboratory. Samples were taken and submitted to the Onderstepoort Veterinary Institute (OVI) for diagnostic analysis.

Initial test results on the first few cases incriminated AHS virus as the cause. New diagnostic evidence, based on virus isolation at the OVI, indicate that there is a distinct probability that other equine disease viruses might also be involved. This likelihood is currently under intensive investigation by the Western Cape Veterinary Services, actively supported by local private-practising equine veterinarians, as well as researchers from OVI and the University of Pretoria's Faculty of Veterinary Science.

Horse owners are requested to report any cases of horses exhibiting suspicious clinical signs (fever reactions in excess of 39 degrees Celsius, coupled to general malaise and/or difficult breathing, sometimes ending in peracute deaths) to their veterinarians, so that the necessary investigations can be done to try and accurately establish the exact cause(s) of these cases.

Various infectious agents able to cause disease in equines are under suspicion, including Equine Encephalosis Virus. African horse sickness virus has also not been eliminated as the cause of the current disease outbreak, whether alone or possibly in combination with other infectious organisms. As outbreaks of AHS directly impact on the export of horses from the AHS Free Area, the real cause of these cases would have to be established to the satisfaction of the World Animal Health Organisation (OIE) and the veterinary authorities of our equine trading partner countries.

As the cause(s) of these cases have not been unequivocally confirmed by laboratory isolation and identification of the causative agent(s), the current movement ban would have to be maintained, in fact even extended, as detailed below.

The current ban, issued as a Notice in terms of the Animal Diseases Act, 1984 (Act 35 of 1984, as amended) will come into effect on the issue date of this Notice and will now include the following restrictions and areas:

1. A total ban on all movements of equines (horses, donkeys, mules and zebra) within, into, through or out of the whole of the African horse sickness Surveillance Zone and AHS Free Area (see description of areas and map attached hereto).

2. This ban will be in operation until cancelled by a Notice issued similarly as above.

3. Cancellation or modification of this Notice will only be considered once the Veterinary Authorities have determined the exact cause and possible effects of this pathogen and established the necessary disease control strategies.

4. The above movement ban includes movements of equines out of the areas specified above to the rest of the country. This differs from the previous ban in that AHS was the only consideration then, but now unknown factors have to be taken into consideration.

5. Previously the ban allowed for movement in and between other districts, not specifically mentioned as high risk areas, under cover of a State Veterinary Movement Permit. For the whole of the AHS Surveillance Zone and Free Area this has now been cancelled as indicated in 1. above.

6. All pertinent authorities (inclusive of the Provincial and Municipal Traffic Inspectorates and the SA Police Services) will be requested to police this ban and take appropriate action against transgressors.

7. The need and applicable areas for compulsory vaccination against African horse sickness will be revised and communicated shortly. Decisions regarding this aspect of disease control obviously depend on laboratory diagnostic results.

Full compliance by all involved parties is a prerequisite in our combined attempts to safeguard our horses, especially as the specific cause of these deaths has not been satisfactorily established. In the face of such an unknown challenge to the whole country's horse population, severe limitation of horse movements is a prerequisite. This, coupled with practices involving excellent feeding, husbandry and biting insect control, is the only disease prevention actions that can currently be advised.

As requested previously, all horse owners and organisers of equine shows, meetings and competitions throughout the country, are urgently requested to postpone imminent major horse gatherings until more clarity with respect to this epidemic is obtained. These are major decisions, but can in the long run, only be advantageous to the local as well as national equine industry and sporting codes.

Description of the African Horse Sickness Surveillance Zone and the African Horse Sickness Free Area

It is the area south of the Berg River (forming the Northern border from it's mouth in the Atlantic Ocean at Velddrift to just south of the Voëlvlei Dam in the East) and to the West of the Hawequa, Du Toit's Kloof, Klein Drakenstein, Franschhoek, and Hottentot-Hollands mountain ranges (forming the Eastern border and stretching from the North opposite Voëlvlei Dam to it's most southerly point of Cape Hangklip).

This area contains the magisterial districts of:

• Moorreesburg
• Vredenburg
• Hopefield
• Malmesbury
• Wellington
• Paarl
• Stellenbosch
• Bellville
• Kraaifontein
• Cape (Milnerton)
• Somerset West
• Strand
• Kuils River
• Mitchell's Plain
• Goodwood
• Wynberg
• Simon's Town

inclusive of the whole Cape Town Metropole.

For more information, please contact your local State Veterinarian or Private Veterinarian, or the following:

State Veterinarian: Boland Office, Elsenburg, Stellenbosch
Tel: 021 808 5253
Fax: 021 808 5125.

Further information regarding the above will also be placed on the following websites:

http://www.nda.agric.za and Elsenburg website

Enquiries:
Alie van Jaarsveld
Spokesperson
Ministry of Agriculture: Western Cape
Tel: 021 483 4930
Fax: 021 483 3890
Cell: 084 604 6701
Email: avjaarsv@pgwc.gov.za