The purpose of this study is to evaluate the efficacy of the Travelers' Diarrhea Vaccine System to actively immunize against Enterotoxigenic Escherichia coli disease in a field setting.

Inclusion Criteria:

• 18-64 years of age at date of first vaccination
• Good health as determined by medical history and physical inspection
• Females of child-bearing potential must have a negative pregnancy test prior to first vaccination in teh Country of Origin; females of child-bearing potential must agree not to become pregnant throughout the duration of the study
• Subjects must have planned travel to an area within 3 hours traveling distance of Mexico City, Cuernavaca, Guadalajara, Oaxaca, or San Miguel de Allende, Mexico or Antigua, Quezaltenango, Guatemala City, or Solola, Guatemala for a minimum duration of stay 7 days (no maximum stay is specified for inclusion).
• Subject must be able to communicate in English

Exclusion Criteria:

• Abnormalities as determined by the Investigator/clinician during physical inspection
• Participated in research involving investigational product within 30 days before planned date of first vaccination
• Ever received LT, ETEC, or cholera vaccine
• History of diarrhea while traveling to a developing country within the last year
• Women who are pregnant or breastfeeding
• Clinically significant underlying enteric, pulmonary, cardiac, liver or renal disease
• History of Irritable Bowel Syndrome
• Seizure disorder within the last year
• Current use of immunosuppressive therapy (excluding inhaled steroids) or current immunodeficiency
• Known or suspected alcohol abuse or illicit drug use within the last year
• Medical history of HIV, HBV, or HCV
• An employee of a study site
• Known allergies to any component of the vaccine, including adhesives
• Planned use of antibiotics with known activity against gram negative facultative anaerobes
• Planned use of antacids, antidiarrheals, loperamide, bismuth subsalicylate, diphenoxylate or similar during the surveillance phase of the study
• An employee of Intercell (global) or an immediate family member