Mounties say their signature Musical Ride tour could be back on the road by the end of the month, now that a number of the highly skilled horses are recovering from an infection with "strangles."

The Mounties were forced to cancel a number of appearances, including one at the Calgary Stampede, after several horses stopped eating during the Quebec leg of the tour a few weeks ago.

During their Canada Day performance on Parliament Hill in Ottawa, some of the animals looked thin, skittish and became difficult to control. The horses' vet was called in to inspect them and to take samples.

One of the horses was diagnosed with the respiratory infection known commonly as strangles, while eight more showed symptoms of the bug.

Strangles, or Streptococcus Equi, is a common upper-respiratory illness that's common in central Canada. It swells a horse's glands and, if untreated, can restrict their breathing and can even cause death.

The illness isn't dangerous to humans, although they can help pass it from one horse to another.

"It's a very contagious disease and can spread quite quickly through a barn," said veterinarian Ben Henderson.

The vet ordered that the horses be isolated at RCMP stables in Ottawa, to prevent the illness from spreading, and prescribed medication. He also advised the Mounties to cancel travel plans for the Ride between July 2 and 20 while the animals receive treatment.

"This is the first time in 60 years, that we know of, that we've had to cancel a portion of the tour," RCMP inspector Marty Chesser told CTV News.

The affected horses are still allowed to perform while they recover, RCMP said, but only near their home base in Ottawa.

Doctors are now testing to see if the medication has worked. If the results of three tests for the illness come back negative, the horses can resume their tour. So far, two have come back negative and they're now waiting for the results of a third test.

If that one shows that the troop is in the clear, the Musical Ride can perform at a show Edmonton on July 23.

With a report from CTV's Richard Madan and files from The Canadian Press