DENVER -- The Muscular Dystrophy Association (MDA) announced Monday it is immediately canceling the remainder of its annual summer camp program, including a camp in Colorado, because of concerns about the H1N1 virus.

A MDA camp at Rocky Mountain Village in Empire ended last Friday. The camp scheduled to start Sunday has been canceled. Fifty-three kids were scheduled to attend the camp.

No H1N1 virus has been reported in the Colorado camp.

Approximately 1,800 children attended 33 MDA summer camps in the past month. Another 2,500 children were scheduled to attend the remaining 47 camps that have now been canceled.

Eleven cases of swine flu were reported after the children left camp in three other states. Six suspected cases have been reported at the MDA Summer Camp in Worcester, Pa., which ends Tuesday.

"These children are much more vulnerable because of their weakened respiratory muscles, so we are taking this preemptive action to protect them from possible exposure to the swine flu," Dr. Valerie Cwik, MDA's medical director, said in a news release.

On Friday, MDA conferred with officials at the Centers for Disease Control and Prevention in Atlanta, who concurred with the decision to cancel the camps as being "the prudent thing to do" based on the fact that these children are at such high risk for complications from the flu virus.

Still, parents of children who were supposed to attend the camp in Colorado said it was a disappointment.

“We were worried about telling Alonzo because it’s something he looks forward to all year long,” said Karen Dunovan, whose son, Alonzo, 13, has been to the MDA Camp for the last seven years. “He took it in stride pretty well.”

Her family had planned a Colorado vacation during the camp and had to adapt their plans.

“Just getting him in and out of the cabin we rented is challenging,” said Dunovan. “But any exposure to that virus would be life-threatening, so if the CDC says that’s what they need to do, they need to follow those recommendations.”

Easter Seals Colorado runs Rocky Mountain Village, and Lynn Robinson, the CEO, said the H1N1 concerns may be overblown.

”We work with children at risk all the time and we are very careful, and I do think if they are going to be in any kind of congregate setting, this is the place they should be,” said Robinson.

She said because of the short notice Easter Seals Colorado had already spent more than $50,000 on staffing, preparations and food for the MDA camp.

“Of course, this year with all our other problems, that’s a huge hit for us,” said Robinson.

The campgrounds aren’t completely empty this week, though.

Easter Seals scrambled to find about 20 campers from its waiting list who were able to come at the last minute.

The rest of the summer camps scheduled at Rocky Mountain Village will be held.