To describe clinical, immunological, and virological characteristics of persons with acute HIV infection

1. To describe demographics and behavioral risk factors for those identified with acute HIV infection
2. To describe neurocognitive function and neuroimaging findings in acute HIV infection as well as describe immune response, HIV-1 genotypes and sequences in the cerebrospinal fluid.
3. To describe the number and characteristics of sexual contacts
4. To describe the willingness of acute HIV-infected subjects to allow the tracking of their sexual contacts for voluntary HIV counseling and testing (VCT)
5. To describe immune response, HIV-1 genotypes and sequences in the genital compartment
6. To describe T cell depletion in the gut mucosa in acute HIV infection and describe the changes in gut T cell during follow up
7. To archive samples for future investigations including determination of viral evolution, and cell-mediated and humoral immune responses in peripheral blood and mucosal compartments

This study will establish an acute infection cohort which is predominantly non-subtype B. Description of the early events in HIV infection is critical to HIV vaccine development and understanding HIV-1 immunopathogenesis. The ability to establish this cohort and identify individuals with acute HIV-1 infection would provide the basis for future hypothesis-driven proposals.

Subjects will be recruited at the TRCARC. Subjects seeking VCT will be asked to provide contact information. Blood samples, either plasma or whole blood collected on filter paper (dried blood spots, or DBS) will be screened for acute HIV infection by pooled or individual NAT if non-reactive after screening by an EIA capable of detecting both HIV antibody and antigen (4th generation or sensitive EIA). Additionally, 4th generation reactive samples will be screened with a non-IgM sensitive EIA capable of detecting HIV antibody only (less sensitive EIA) within 1-2 days of sample collection. Those who are found to have acute HIV infection will be asked to enroll in the cohort study. These acute HIV-infected participants will be followed prospectively at week 0, day 2, 3, 5, 7, 10 then weeks 2, 4, 8, 12, 16, 20, 24, then every 12 weeks until the end of the study (maximum of 192 weeks of follow up). Subjects will receive blood testing for CD4, HIV RNA, ALT, creatinine and lipids, and urinalysis. Subjects will be asked to complete a questionnaire on HIV risk behavior. Archiving of plasma and PBMC for future immunologic and virologic testing will be performed. Optional study procedures include 1) collection of genital secretions 2) collection of cerebrospinal fluid 3) brain MRI/MRS without gadolinium 4) sampling of gut-associated lymphoid tissue by colon biopsy 5) genetic testing 6) tracking of and offering VCT to sexual contacts of acute HIV-infected subjects. Subjects are encouraged to be hospitalized for the first 3-7 days for post-procedural observation and for ease of follow up.

Inclusion Criteria:

1. Age >18 years old
2. Have protocol-defined acute HIV-1 infection (Tested 4th generation HIV EIA negative and NAT positive or tested 4th generation HIV EIA positive, negative by less sensitive EIA and NAT positive)
3. Understand the study and sign informed consent form. Persons who cannot read will have the consent form read to them by a study staff and they can give informed consent by using thumb print.
4. Availability for follow-up for the planned study duration

Exclusion Criteria:

1. Persons who have a history of a medical or psychiatric disorder by investigator's interview and physical examination according to standard practices, that in the judgment of the investigator(s), would interfere with or serve as a contraindication to adherence to the study protocol or ability to give informed consent.
2. Female participants who are pregnant at the time of screening

The population seeking VCT at the TRCAC will be screened. They are comprised of both men and women of different ages, economic stratus and education level: a large portion of whom are at high risk for HIV infection through commercial sex work and MSM.