During the summers of 1980 and 1981 Campylobacter jejuni was isolated from 23% and Giardia lamblia was isolated from 8% of persons with diarrheal disease acquired in the area of Grand Teton National Park, Wyoming. Campylobacter enteritis occurred most frequently in young adults who had been hiking in wilderness areas and was significantly associated with drinking untreated surface water in the week before illness (p less than 0.02 in 1980; p less than 0.005 in 1981). Penner serotype 4 was the commonest serotype isolated from humans and the only serotype isolated from an implicated mountain stream. These studies show that backcountry surface water can be an important source of C. jejuni and that infection with Campylobacter, as well as G. lamblia, should be considered as a cause of diarrhea in those who have recently returned from wilderness areas.

Campylobacter jejuni is an important cause of human diarrheal disease throughout the world and likeSalmonella enteritidis, has a large animal reservoir which includes most of man's domestic animals. Until recently, it has been difficult to trace the chain of transmission from animals to man because of inadequate environmental sampling techniques and means to distinguish strains. Recent improvements in these techniques have made environmental studies more feasible in 2 water-related out-breaks.In 1 study,C. jejuni was found to be an important cause of sporadic, summertime diarrheal disease among hikers in national wilderness areas of Wyoming. In this setting, illness was significantly associated with drinking untreated surface water. SubsequentlyC. jejuni was isolated from surface water, including mountian streams, and from animals in the area. Some of the environmental isolates were serotypically identical to strains isolated from humans.A second study occurred as a result of an outbreak of Campylobacter enteritis in a community in northern Illinois which was epidemiologically associated with the community water system.Campylobacter jejuni was isolated from several surface water sources and from the implicated water system. These studies demonstrate that environmental isolation ofC. jejuni is now possible and may add to our understanding of disease transmission.