Patient description: A 34 year old man comes to the clinic complaining of dizziness and severe diarrhea since yesterday. He has returned from an international trip few days ago and was living in a camp in Sudan for a month. He developed abdominal pain followed by bloating and nausea as well as loose bowel movements. Soon he was having profuse watery diarrhea without odor. The stool is watery and white but the patient has no fever. Blood pressure is 95/62 lying down and drops to 75/40 standing. The skin turgor has reduced. HR is 110 and he looks ill with dry mucosa. V. cholerae was seen in dark-field microscopy of a fresh stool specimen. The lab study is as bellow: Sodium 137 meq/L Potassium 2 meq/L Chloride 94meq/L CO2 15 meq/L Fecal leukocytes None seen Fecal occult blood Negative

Clinical trial eligibility criteria: eligible ages (years): 18.0-40.0,  Escherichia Coli Infections Sign an Institutional Review Board-approved consent prior to any study-related activities Initiate screening 21± 7 days prior to admission or enrollment Must accomplish all laboratory and diagnostic examinations at 21± 7 days prior to admission or enrollment Be at least 18 years of age but not older than 40 years of age at the time of enrollment Be otherwise healthy with a stable address and telephone where the volunteer can be contacted Be able to read and write English Possess a social security number in order to receive compensation Female participants must have a negative serum pregnancy test at screening and a negative urine pregnancy test on the morning of the challenge and use effective birth control during the entire study period. Methods of effective birth control complete abstinence, the use of a licensed hormonal method, intrauterine device, barrier method plus spermicide, or having sexual relations exclusively with a vasectomized partner. Appropriate barrier methods condoms, cervical sponge, and diaphragm. Females who are not of childbearing potential are defined as those who are physiologically incapable of becoming pregnant, including any female with tubal ligation or who is postmenopausal. For purposes of this study, postmenopausal status will be defined as absence of menses for at least 1 year Be seronegative for antibodies to dispersin Have normal laboratory screening values including a white blood cell (WBC) count, hemoglobin, hematocrit, platelets, blood urea nitrogen, glucose, creatinine, alanine aminotransferase (ALT), aspartate aminotransferase (AST), quantitative immunoglobulins, T cell subsets (CD4 and CD8), urinalysis  Has acute or chronic medical illness (i.e., renal or hepatic disease, hypertension, diabetes mellitus, coronary artery disease, malnutrition, obesity (body mass index >30 kg/m2), HIV, corticosteroid use, cancer or receiving chemotherapy, chronic debilitating illness, syphilis) Has used antibiotics within 7 days of challenge Has used medications or drugs, including over-the-counter medications such as decongestants, antacids (calcium carbonate or aluminum-based antacids, H2 blockers), anti-diarrheal medications (such as bismuth subsalicylate or loperamide), antihistamines within 7 days of challenge Has a history of chronic gastrointestinal illness, intra-abdominal surgery, chronic functional dyspepsia, chronic gastroesophageal reflux, documented peptic ulcer disease, gastrointestinal hemorrhage, gallbladder disease, inflammatory bowel disease (Crohn's and ulcerative colitis), diverticulitis, irritable bowel syndrome or frequent diarrhea Has a history any of the following psychiatric illness(es) Depression not controlled with current drug therapy or involving institutionalization Schizophrenia or psychosis Suicide attempt Has a history of or current alcohol or illicit drug abuse Is unable to remain as an inpatient in the University Clinical Research Unit for up to 8 days