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): 18.0-999.0,  Acquired Immunodeficiency Syndrome Healthy Volunteers HIV/AIDS HIV Diarrhea Human Immunodeficiency Virus Voluntary informed consent from the subject to be obtained in accordance with requirements of the Institutional Review Board (IRB) before any study-related activities are performed. 2. Body Mass Index (BMI) between 18 and 32 kg/m2 (both inclusive). 3. Females of child-bearing potential must have a negative serum pregnancy test result at Screening and a negative urine pregnancy test at Visit 2. for Healthy, HIV-negative Volunteers 4. No history or evidence of clinically relevant medical disorders as determined by the investigator. 5. No history of chronic diarrhea or loose stools and/or non-specific incidence of acute diarrhea or loose stools between the Screening Visit and Baseline Visit 2 (Day 1). applicable to all PLWHA subjects 6. Male and female patients receiving a stable CART for ≥ 4 weeks for HIV treatment. 7. Have a history of diarrhea (persistently loose stools despite periodic or regular use of antimotility medications) or ≥1 watery bowel movement per day (without periodic or regular use of antimotility drugs); i.e diarrhea for a continuous period of ≥1 month. for PLWHA males and females receiving CART fully suppressed HIV RNA counts 8. CD4 counts >200/µL at the Screening Visit. 9. Plasma levels of HIV RNA greater than 1,000 copies/mL at the Screening Visit. for PLWHA males and females receiving CART WITH fully suppressed HIV RNA counts 10. CD4 counts >400/µL inclusive at the Screening Visit. 11. Plasma levels of HIV RNA < 50 copies/mL at the Screening Visit  Applicable to ALL subjects 1. Any serious systemic disease or infection (other than HIV in PLWHA) that occurred within four weeks prior to Screening, as determined by the Investigator. 2. Patients with active bacterial or parasitic infections requiring antibiotics or antiparasitic agents will be excluded. Antibiotic or antiparasitic agents used for prophylaxis are acceptable until 7 days prior to treatment initiation. 3. Stool cultures that are positive for any pathogenic infection at screening visit. 4. Clinically significant cardiovascular disease will 1. History of stroke, transient ischemic attack, or myocardial infarction within 6 months prior to Screening. 2. History of or currently have New York Heart Association Class III-IV heart failure prior to Screening. 5. Female subject who is pregnant or breast-feeding or intends to become pregnant or is of childbearing potential and not using adequate contraceptive methods. 6. Subject has participated in another clinical study, involving an Investigational Product or an Investigational Device use in the past 1 month prior to commencement of this study. 7. Use of Mytesi (crofelemer) within 4 weeks of the Screening Visit Applicable to ALL HIV-negative subjects 8. Positive for Human Immunodeficiency Virus (HIV) antibodies, hepatitis B surface antigen (HBsAg), hepatitis B core antibody or hepatitis C antibodies (HepCAb). 9. Presence or history of cancer within the past five years except for adequately treated localized basal cell skin cancer or in situ uterine cervical cancer. 10. Chronic diarrhea or loose stools requiring antimotility medications including, but not limited to loperamide, diphenoxylate/atropine, tincture opium and/or octreotide within 2 weeks of the Screening Visit. Applicable to ALL PLWHA subjects 11. HIV Patients with infectious diarrhea identified by either stool culture