Both of the horses infected at The Crags had been vaccinated against AHS. "We know that vaccines are not 100% effective," explained Dr Edwin Dyason, a state veterinarian. Vaccination is one of the precautionary measures which can be taken, although there are many factors which contribute to the efficacy of vaccinations.
According to Dyason, the older a horse is and the more vaccinations it has had the less likely it is to die in the event of contracting AHS, provided the horse has been well taken care of in terms of nutrition and exercise.
A third suspected case has been reported in the Knysna area. Although it has not been confirmed symptoms suggest that AHS was highly likely in this instance, and caused the horse’s death. It is suspected that the horse had been ridden from an area close to the initial cases.
"These are the first cases of African Horse Sickness reported in the Southern Cape since 2006/2007, when over 80 horses died along the Garden Route in a sudden outbreak that took all horse owners completely by surprise," explained Kathy Wiles, who manages the Blanket Vaccination Programme in the area on behalf of the African Horse Sickness Trust. She continued, "Due to that outbreak having been the first for this area in close to 100 years, many horses had never been vaccinated against AHS at the time - with devastating consequences - as the death rate in unvaccinated horses can be as high as 85%.”
Since the 2006 outbreak, an annual vaccination programme has been implemented aimed at educating and creating awareness amongst horse owners, while at the same time building a 'firebreak' by vaccinating as many horses as possible in areas where they would not normally be vaccinated.
According to Wiles, the greatest danger lies with large herds of unvaccinated horses or large herds of zebra, which can create a pool for the virus. Zebra are able to host AHS and remain completely unaffected by it; as such they can be carrying the virus without showing any symptoms.
The current AHS laws do not apply to zebra and they are not tested for AHS before being moved to new areas, with the exception of zebra being moved into the AHS Control Area of the Western Cape. (See map-BELOW)
As a precautionary measure, private veterinarians have been notified by the state veterinarians not to allow the movement of horses from the Garden Route toward Cape Town in order to safeguard the AHS free surveillance and protection areas.
Dyason explained that horses in the surveillance zone are generally not vaccinated so that they can be used as a control group, and as such it is of the utmost importance that these horses are not exposed to the AHS virus.
"Horse owners really have to take responsibility for protecting their own horses against AHS, as well as making sure they are not posing a threat to other horse owners in the area, by neglecting to vaccinate, or by moving their horses around during outbreaks in the area. Added to this, is the fact that all horse, donkey and mule owners are obliged by law to vaccinate against AHS every year, as well as to report any suspected cases of AHS, as it is an internationally notifiable and controlled disease," explained Wiles.
The correct time to vaccinate horses is September/October each year; as this allows them time (2 to 3 months) to build up good immunity before AHS season starts from around December/January to around April/May.
"Apart from vaccinating, horse owners should take all other precautions possible to give their horses extra protection against the bites of midges which transmit the virus. These tiny midges, called Culicoides, pick up the virus after taking a blood meal from an infected horse and will then pass it on to any other horses they bite," said Wiles.
Dyason suggested that horses should not be exposed to Culicoides midges. He recommended stabling horses from before sunset until after sunrise, preferably on higher ground as Culicoides midges are more active at night and in low-lying areas.
Dyason also recommended the use of insect repellents as a precautionary measure.
According to Wiles, recent research proved that citronella Oil was ineffective and may even attract Culicoides midges.
To keep up to date with the latest news regarding outbreaks of AHS or to get more information on the disease and protection measures, horse owners can visit www.africanhorsesickness.co.za or contact Kathy Wiles at (044) 877 1825 for further information.
ARTICLE: Candice Ludick
