Wilderness Acquired Diarrhea - Diagnosis

Diagnosis

It may be difficult to associate a particular case of diarrhea with a recent wilderness trip of a few days because incubation of the disease may outlast the trip. Studies of trips that are much longer than the average incubation period, e.g. a week for Cryptosporidium and Giardia, are less susceptible to these errors since there is enough time for the diarrhea to occur during the trip. Other bacterial and viral agents have shorter incubation periods, although hepatitis may require weeks.

A suspected case of wilderness acquired diarrhea may be assessed within the general context of intestinal complaints. During any given four-week period, as many as 7.2% of Americans may experience some form of infectious or non-infectious diarrhea. There are an estimated 99 million annual cases of intestinal infectious disease in the United States, most commonly from viruses, followed by bacteria and parasites, including Giardia and Cryptosporidium. Giardia alone may infect up to 10% of Americans at any one time. However, because most carriers are asymptomatic, there are only an estimated 2 million U.S. cases of symptomatic giardiasis annually spread mostly by fecal-oral or food-borne transmission.