High Fecal Hand Contamination Among Wilderness Hikers
Gastrointestinal complaints, including gastroenteritis, are common among users of the backcountry. While much attention has been devoted to the link between enteric infection and wilderness water, the evidence supporting this connection is nil. On the other hand, fecal-oral transmission between individuals is a highly prevalent and efficient mechanism, proven in countless epidemiologic investigations. No study has examined the potential role for hand-to-mouth fecal transmission in the backcountry.
This study examined the prevalence of hand contamination with fecal organisms in a total of 72 individuals recruited from various sites in the New York Adirondack mountains. After completing a brief questionnaire, a standardized technique was used to rinse the dominant hand in saline; samples were transported to the bacteriology laboratory on ice. In the lab, organisms were isolated by filtration onto polycarbonate, followed by elution and inoculation onto various agars. Coliforms were identified and confirmed by appropriate biochemical testing.
Overall, 31% of the samples were positive for coliforms, confirming fecal contamination of hands. There were no statistically significant differences between individuals entering or exiting the backcountry. Similarly, there was no association between the presence or absence of contamination and self-reported hand hygiene habits.
These data should inform outdoor educators as they discuss trek hygiene. Since nearly a third of backcountry users may carry fecal material on their hands, attention should be paid to food preparation, sharing of food from common containers, as well as hand-washing or the use of chemical gels. In contrast to North American wilderness waters, which have never been shown to have meaningful fecal contamination, trek participants themselves may well be reservoirs of enteric disease.
(Am J Infect Control. 2012 Mar 14 [Epub ahead of print]). DS Kellogg, PF Rosenbaum, DL Kiska, et al.
Prepared by Brian Vu, MD, UT Houston Emergency Medicine, Houston, TX, USA