The patch, which is produced by the biotechnology company Iomai, is currently in the Phase-2 evaluation and the results of a field study revealed that the patch significantly cut the risk of moderate to severe travelers' diarrhea by 75 percent compared with a placebo patch. The few vaccinated travelers who were sickened had illnesses that were significantly shorter and milder.

During the field study the researches have evaluated 170 healthy adults who traveled to Maxico and Guatemala, geographical regions known for as a risk zones for travelers' diarrhea.

The illness is caused by bacterial enteropathogens, E. coli being responsible for approximately 80 percent of the cases, followed by another bacteria called Shigella.

The onset of traveler’s diarrhea usually occurs within the first week of travel but may occur at any time while traveling, and even after returning home. Most cases begin abruptly. The illness usually results in increased frequency, volume, and weight of stool. Altered stool consistency also is common.

Typically, a traveler experiences four to five loose or watery bowel movements each day. Other commonly associated symptoms are nausea, vomiting, diarrhea, abdominal cramping, bloating, low fever, urgency, and malaise, and usually the appetite is low or non-existent .

This year, approximately 55 million international travelers will visit countries where bacteria that cause travelers' diarrhea are endemic, particularly Africa, Asia and Latin America, and about 20 million of those travelers will develop travelers' diarrhea.

Form the 170 people involved in the Iomai’s study 59 have received the real patch, while 111 have received a Placebo patch.

The results showed 22% of those who got the placebo patch developed diarrhea compared with 15% of those who got the vaccine patch.

Iomai said that is targeting an end-of-Phase 2 meeting with the U.S. Food and Drug Administration in 2008 prior to conducting the pivotal Phase 3 study in 2009.