PONY owners in the New Forest are on high alert today after a major outbreak of a potentially fatal disease.

Dozens of animals have been struck down by strangles, a highly contagious respiratory infection that kills scores of equines in the UK each year.

Two round-ups and a pony sale have been cancelled in a bid to stop the disease – which is spreading like never before, making it almost impossible to predict where it will strike next.

And riders exercising their horses in the Forest are being urged to keep them away from the thousands of ponies that graze the landscape.

Round-ups, known as drifts, were due to be staged at Burley Rocks on Sunday, September 7 and Burley Lawn on Sunday, September 14, but animals in the two areas are among those that have developed the disease.

Sue Westwood, clerk to the Verderers, said: “We’re looking at each area and won’t drift where the problem is bad.

“Herding ponies together in a pound would risk spreading the infection and the agisters don’t want their horses getting too close to any infected ponies.

“It’s not following the pattern it usually does.

“In the past it would start in one place and go to neighbouring areas.

“This time areas are being missed out, so it’s impossible to predict.”

The outbreak of the disease began in the Lyndhurst area in the spring and then spread on to Brockenhurst.

Ponies in Hill Top and Blackfield have also been affected.

The vast majority are expected to recover, but at least one animal is known to have died.

The Animal Health Trust (AHT) is spearheading attempts to develop a new vaccine to help combat the disease.

An AHT spokesman said: “Strangles is a very unpleasant and potentially fatal disease, which causes a great deal of suffering.

“However, with care, outbreaks can be controlled and the worst effects can be avoided.”

New Forest Livestock Society confirmed that a sale which was due to have been held at the Beaulieu Road yard on Wednesday, September 10 had been cancelled following the outbreak.

A spokesman said the sales events attracted animals and their owners from across the country and added: “We knew we had to act responsibly and follow what the other organisations were doing.

“We don’t want to spread the problem.”

New Forest ponies are owned by commoners – villagers with the right to let their animals graze the area.

Graham Ferris, chairman of the Commoners’ Defence Association, said he fully supported the steps which were being taken to stop the disease from spreading.