South African authorities are urging horse owners to vaccinate their animals annually in an effort to curb the impact of African horse sickness.
African horse sickness is a controlled animal disease under the country’s Animal Diseases Act, 1984 and all suspected or confirmed cases must be reported to the nearest state veterinarian.
The disease is transmitted by Culicoides midges and not by direct spread from horse to horse.
Favourable climatic conditions, including summer rainfall, may increase the breeding and spread of the midges. Heavy rains preceded by a prolonged dry spell favour the occurrence of epidemics.
The number of outbreaks decline after the first frost and normally the disease disappears abruptly in May.
Owners are being encouraged by the Department of Agriculture, Forestry and Fisheries to vaccinate their animals before the start of the rainy season to limit the impact of the disease.
As an extra measure, it is advisable to stable horses for at least two hours before sunset and keep them stabled for at least two hours after sunrise as this is the period when the midges are most active and known to be feeding.
The midges also colonize around stagnant water sources and efforts should be made to prevent pooling of water and to move animals away from water sources.
All horses in South Africa, except those in the designated free and surveillance zones in the Western Cape, have to be vaccinated annually using a registered vaccine at the cost of the owner. Currently, the vaccine from Onderstepoort Biological Products is the only registered vaccine.
For the 2013 cycle, the reporting season started in September 2012 and will continue to August 2013.
This reporting period is chosen because the disease normally occurs during the summer months; and from December to May in particular. During this season, forty three outbreaks of AHS were reported to date in the following provinces; Eastern Cape 19, Gauteng 9, KwaZulu-Natal 8, Mpumalanga 4 and North West 2.
Agriculture authorities declared an area in the Western Cape as a controlled area and includes a disease-free area to facilitate trade. The current controlled area was adopted in 2001. Horses can be exported directly to the European Union from the AHS free area.
In an effort to protect this area, all movements of horses to the controlled areas are subject to state veterinary movement control, with permits required, to prevent the introduction of the virus into the free zone.