
Tour companies say the vast majority of the more than 50,000 cyclists traveling down the mountain yearly are on guided tours.
But companies offering tours without guides have increased in the last several years. There are at least four, compared with three that offer guided tours.
Commercial bicycle tours with no guides have been banned at Haleakala National Park.
Chief ranger Karen Ardoin says guided tours have an employee riding in the front to control the pace and a tour van in the rear that may be used by riders in an emergency.
"We're looking for a needle in a haystack," said Alana's mother, Adelia Chung. "The chances are 1 in 19,000 if Asian and 1 in 20,000 if it's non-Asian.
"It may be rare, but it happens."
Public response to the family's plea has been overwhelming.
The Hawaii Bone Marrow Donor Registry, for example, could not process all of the 1,000 donor volunteers yesterday on the first day of the Hawaii Dental Association convention at the Blaisdell Center exhibition hall.
"We'd love to find one for her," Stephen Dung, Alana's father, said, "but even if it didn't happen, what a joy it would be if we could find donors for six other kids."
The family has created an Internet site on how to help; the address is http://www.hula.net/~idc/alana.html

He died a half-hour after he was found about 9:40 p.m. on the roadway fronting the Alakea entrance to the Hawaiian Tel building.
The man suffered head, leg and internal injuries consistent with being hit by a car, traffic investigators said.
Police are looking for witnesses. Anyone with information is asked to call 529-3499.
The man, allegedly under the influence of painkillers, was driving away from his Booth Road home around 4 p.m. yesterday when the woman, 39, apparently lay on the roadway to try to stop him, police said.
The man apparently saw the woman but continued driving toward her, hitting her with the front bumper and rolling her over, police said.
She suffered bruises and abrasions on both shoulders and arms.
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