HIV/AIDs ph 370 exam 2

hypothesis development

• male- 30, previously healthy

• gay, frequent sex, drug use

• conditions associated w immune suppression

ebidemiologic observations

• disease in newborn babies

• disease in heterosexual patients who had surgery

• lack of cases in healthcare workers

identifying the etiologic agent: evidence

• drastically reduced t-cell count

• blood borne and sexually transmitted pathogen

• only viruses known to target t-cells were retroviruses

• identified by 3 separate labs

• 1986 renamed human immunodeficiency virus

need for public health

• focus on education to curb higher risk behavior and slow transmission

• need to unite unnatural partners

• established rapid and clear info dissemination mechanisms

• 1986: US surgeon general sent info report to houses in US

what are some of the characteristics of HIV (retrovirus)

• stores genetic info as RNA

  • need to make DNA using host cells material

• spherical particle

  • external lipid bilayer envelope

  • internal protein core

what does the core of HIV contain

• RNA

• reverse transcriptase

• integrase

• protease

what is the HIV life cycle

1) HIVs envelope glycoprotein binds to CD4 receptor on human CD4 + cells and allows 2nd binding to WBC receptors, CCR5 or CXCR4

2) HIV enters cell; remove/ exposes capsid; single-stranded RNA converted to double stranded DNA using reverse transcriptase

3) DNA moves to nucleus where it integrates in human DNA by integrase viral DNA copied when human DNA copied; viral proteins produced when human proteins produced

4) with help from enzyme protease, viral proteins from new HIV particle leave cell, mature and infect other cells

How does HIV damage immune cells

• integrase and protease also activates apoptosis w/ in CD4 and cell

• specific HIV protein remain displayed on surface of infected CD4 and T cells

• immune system further reacts and produces antibodies to further identify infected CD4 and T cells

• activation of inflammatory cascada inside infected cells—> signals apoptosis

what were some important lab discoveries

• HIV mutates rapidly; up to 1000x faster than flu

  • challenge for vaccine

• key points in virus life cycle identified

  • if interrupted, can halt spread of virus

Transmission of HIV

• 100% preventable if proper precautions in place

• requires exchange of body fluids

• sexual transmission

  • HIV is semen, vaginal cervical fluids

  • direct transmission into blood stream on highest risk; concern of micro tears

• blood transmission

  • blood transfusion with infected blood

  • needle sharing-illicit drugs, steroids, tattoos, piercings

• mother-to- child transmission

  • during birthing process, breastfeeding

DIagnostic testing for HIV

• ELISA test

  • measures antibodies in blood

• western blot-assats for specific viral protein

• viral load

How does HIV infection turn into AIDS disease

• healthy adults have CD4 count of 850-1000 CD4 cells per cubic meter of blood

• after infection, HIV viral load high but antibodies just being produced CD4 count—> unchanged

• several months after infection— viral load decreased because virus inside cells; HIV antibodies rising; asymptomatic period—> can last months to years

• viral replication continues, CD4 cells destroyed

• AIDS: immune system compromised and unable to fight off infections

reverse transcriptase inhibitors

block ability for transcription of virus RNA into a double-stranded DNA

protease inhibitor definition

interfere in vial assembly process so reduce virus load to attack other cells

• initially result in aromatic reduction of virus in blood rapidly rebound when stop medication

vaccines of HIV

VIR-1388: tells immune system to produce T cells that can recognize HIV and signal immune response, uses CMV vector

PrEP

• can be taken by HIV (-) people at high risk for HIV infection to prevent HIV

• combination of 2 medications- sold as truvada

• PrEP interferes with HIV ability to reproduce so body can fight off virus

• when taken daily

  • decrease HIV risk from sex by 99%

  • decrease HIV risk from injecting drug use by 74%

  • need to take 7-20 days before effective

  • can be 2,000/month

what are the challenges of PrEP

• limited geographical access

• lack of medicaid expansion

• low rates of health insurance

• barriers: poverty, systemic racism, homophobia stigma

• cost

how do we end the HIV epidemic

• diagnosing

• treating

• protecting

• responding