Look out for these symptoms of African Horse Sickness

High rainfall and humidity have resulted in outbreaks of African Horse Sickness, says Dr Mac.

Look out for these symptoms of African Horse Sickness
- Advertisement -

At the time of writing, there have been 23 confirmed cases of African horse sickness (AHS) in South Africa. Of these, 14 were in KwaZulu- Natal.

The authorities have mentioned that the severity of the outbreak was unexpected. What does this mean to you as a concerned horse owner?

The obvious first step is to monitor your horse for AHS. Some people maintain that you can detect the disease early if you take the horse’s temperature twice daily.

- Advertisement -

However, increases in rectal temperature can also be caused by hot stables, blanketing or even exercise, such as galloping home for supper – but the practice will at least force you to observe your horse more regularly.

As fever is also caused by other diseases, such as respiratory tract infections or tick fever, it is better to look for other signs:

  • A change in respiration rate, often from about 18 breaths/minute to more than 35. In very severe cases, where the horse is likely to die within 24 hours, the respiration may also be unduly slow. And abdominal breathing – using the stomach muscles to draw breath – can be seen.
  • Swelling of the supraorbital fossa, the hollow above each of the horse’s eyes. In mild cases, this disappears when the horse recovers. In more severe cases, it develops into a swelling of the entire head, neck and underparts of the body, from the brisket, or chest, to the chest and abdomen. This is because the AHS virus damages the endothelial cells of small blood vessels, allowing blood serum to leak into the tissues and lungs.

Prevention
At this stage, it is too late to vaccinate. Research has shown that horses vaccinated during an epidemic are more likely to die, as the vaccination decreases immunity for several days.

On the other hand, prevention of contact with midges by stabling horses has been shown to be effective, and midge repellents should be used daily. As AHS can be transmitted by biting flies, ticks and mosquitoes, general parasite control is also advised.

Midges breed in muddy manure-contaminated pastures and survive better in long grass. Such areas should be drained. Agricultural lime can be sprinkled over the mud and mixed in, as it makes soil more alkaline and unsuitable for midge, mosquito and fly larvae. Grass in horse paddocks should be kept short at this time of year.

Treatment
Unfortunately, prevention is far more effective. Unvaccinated horses kept outside have a very high mortality rate. Vets offer supportive treatment, mainly using anti-inflammatory drugs, rehydration and keeping the airways open.

There are also natural remedies that essentially ‘boost immunity’ or ‘relieve symptoms’. These are fairly successful in milder cases where the horse has some immunity or did not get a large dose of the virus because it was stable.