Abstract
To the Editor:
The recent report by Magill-Collins et al 1 on “Norovirus outbreaks among Colorado River rafters in the Grand Canyon, summer 2012” is very interesting. The authors concluded that “norovirus may have been introduced by ill or asymptomatic individuals actively shedding the virus in their vomitus or feces, and spread within, or between, river trips by different modes of transmission.” 1 Indeed, there are many previous reports on the outbreaks in this area. Jones et al 2 mentioned that “since 1994, over 400 rafters in 6 separate outbreaks have become ill with norovirus while rafting this stretch of the river.” Jones et al 2 analyzed the water quality in the Colorado River and concluded that “there is not an ongoing high level of norovirus contamination in the river.”
The source of infection is a very interesting issue. I would like to present an experience with a similar situation. A cluster of gastrointestinal illness among tourists who went rafting was recently seen in my medical center. The identified source of contamination was the food served on the raft. Contamination of cooked food at raft camp was reported as the cause of gastroenteritis in the recent report by Malek et al, 3 who concluded that “meat-processing practices should include specific measures to prevent contamination with enteric viruses.” Nevertheless, in my case, the food was prepared externally and delivered to the raft. There was no environmental contamination in the rafting area, but the contaminated food was delivered from a remote source. At present, many tourists visit rafting resorts for leisure. With good transportation, food delivery to the campsite is common. Similar to environmental control, the quality control of the food served to the rafters is required.