Friday, June 21, 2002 | 10:02 a.m.
Health officials have tentatively identified the cause of a gastrointestinal illness reported by rafters on the Colorado River as a common virus.
The Norwalk virus, named because it was first discovered in Norwalk, Conn., appears to be the culprit in the outbreak first reported by river guides under a new rapid reporting system developed after similar outbreaks in 1994 and 2000, National Park Service spokeswoman Maureen Oltrogge said Thursday.
Norwalk viruses are the most common cause of gastrointestinal illness in the United States. The virus is easily spread through person-to-person contact or inadequate sanitation.
From June 1 to June 14 a total of 51 rafters and one hiker in the Grand Canyon had reported diarrhea and vomiting lasting one to two days. The number of people with the virus was reduced from 59 after a review of the cases.
One problem in pinpointing the exact cause of the outbreak is its symptoms that are similar to heat exhaustion, Oltrogge said. Two separate medical evacuations were conducted for people suffering from symptoms similar to the virus, but caused by dehydration.
Scientists analyzed a single specimen obtained from a portable toilet used by one of the river-running groups to confirm it was a virus.
Additional specimens from other affected river groups and individuals who have suffered from illnesses with the same symptoms are being analyzed.
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