An outbreak of a highly infectious respiratory disease affecting horses has forced the cancellation of a popular event in Rhu. Around 200 horse and pony owners and their riders were due to compete in the Helenburgh Area Show in August.

But the decision has been taken to cancel the event because show equipment is stored at stables which have had outbreaks of the disease, called equine strangles, and there are fears the bacteria could be transmitted.

The cancellation is doubly disappointing as the event - which includes a dog show - was called off last year because of atrocious weather which meant the ground at Ardencaple was waterlogged.

Elise Nash, the show's secretary, said: "It's a big disappointment, especially as we could not go ahead last year. The committee met and took the decision to exercise caution as equipment is stored at various places in the area that are now compromised. It's a very infectious disease and we did not want to take any chances."

The show was due to take place on Sunday, August 4 with entries coming from throughout Argyll and Central Scotland.

Equine strangles, one of the most common equine respiratory diseases in the world, is caused by the bacterium Streptococcus equi and has been a cause of frustration ever since humans started using horses for work and recreation.

The signs of the disease include fever, nasal discharge and depression, and abscesses can also develop around the animal's head and neck.

Although not a notifiable disease, strangles itself can kill (in simple cases there is a one percent mortality rate). But the major reason for its concern is the speed with which strangles spreads among horses, especially in a stable setting.

Several measures can be taken to minimise the risk of strangles on a yard.

A website - www.equine-strangles.co.uk - has comprehensive advice for horse and pony owners, including avoiding contact with horses of unknown origin, reducing sharing of tack or equipment from horses of unknown health status and restricting movement.

Elise said: "I would encourage anyone who has a horse or who rides a horse to look at that website as it contains very useful information."

Riders have expressed disappointment over the cancellation, but many messages posted Helensburgh Area Show's Facebook indicate many think its the right decision.

Wendy Trew posted: "That's a shame but highly commendable that you have taken the strangles illness seriously and are taking steps to minimise the outbreak and spread of it."

A livery yard in Clydebank is in lockdown, with no horse movements in or out.

Colgrain Equestrian Centre near Helensburgh, which has 30 horses, is clear of any infection.

Owner Fiona Spy said: "We have a very good relationship with local vets and a strong policy of being aware of any possible infection and how to act if a situation develops. The more people who are aware of equine strangles the better. If everyone behaves responsibly and sensibly, then there should be no problem. It's about how people react."

The centre has strong links with the British Horse Society who have endorsed Colgrain as an approved riding school, livery yard and facilities centre.

Fiona, whose son James is an equine dentist, added: "We operate strictly within the BHS code of conduct. People would not normally bring horses here, but if they do we ensure we know where they are coming from."