Inclusion Criteria:

HIV-seropositive, non-pregnant adults, aged 18 - 45 years old who have been on standard highly active anti-retroviral therapy (HAART) for at least 6 months prior to enrolment or who have never started HAART regimen will be recruited in the study.

All subjects must satisfy the following criteria at study entry:

1. Male and female HIV seropositive adults aged 18 to 45 years old who have given the written informed consent.
2. Will comply with the requirements of the protocol (i.e. available for follow-up visits and specimen collection).
3. CD4 T-lymphocyte count >500/mm3 for at least 6 months prior to inclusion
4. History of CD4 nadir >150/mm3
5. Viral load (HIV-1 RNA levels) <200 copies/mL for at least 6 months prior to inclusion
6. Stable highly active antiretroviral therapy (HAART) regimen for at least 6 months with no changes in therapy anticipated or never started HAART regimen.
7. Asymptomatic HIV infection as determined by:Medical history, Physical examination, Laboratory tests, Clinical judgment of the investigator

Exclusion Criteria:

The following criteria should be checked at the time of study entry, if any of the following is present then the subject will be excluded from the study:

1. Overt signs of immunodeficiency e.g. oral thrush, rapid weight loss, recurrent pneumonia (i.e. Stage 3 or 4 of the WHO clinical staging system for HIV infection and disease in adults and adolescents
2. Ongoing serious chronic illness (e.g. with signs of cardiac or renal failure)
3. Abdominal pain or cramps, loss of appetite, nausea, general ill-feeling or vomiting in the past 24 hours
4. Presence of V. cholerae 01 or 0139, ETEC, or Shigella, or Cryptosporidium in stool at baseline
5. Intake of any anti-diarrhoeal medicine in the past week
6. Acute disease one week prior to enrollment, with or without fever. Temperature ≥38ºC (oral or otic) warrants deferral of the vaccination pending recovery of the subject
7. Receipt of antibiotics in the past 2 weeks
8. Receipt of live or killed enteric vaccine in the last 4 weeks
9. Receipt of killed oral cholera vaccine in the past
10. Diarrhea (3 or more loose stools within a 24-hour period) 6 weeks prior to enrollment
11. One or more episodes of diarrhea lasting for more than 2 weeks in the past 6 months
12. One or more episodes of abdominal pain lasting for more than 2 weeks in the past 6 months
13. Receipt of blood, blood products or a parenteral immunoglobulin preparation in the previous 6 months
14. Receipt of any immunosuppressive therapy during the past 6 months
15. A woman pregnant or planning to become pregnant during the period of subject's participation
16. Any condition which in the opinion of the investigator, might interfere with the evaluation of the study objectives