HIV & AIDS

Pages 919-921; IB Topic 6.3

Turn and Talk

What do you know or think of HIV & AIDS?

Talking Point

http://www.nytimes.com/1987/09/01/opinion/on-my-mind-our-house-in-arcadia.html

Introduction

Human immunodeficiency virus (HIV) is the virus that eventually results in a set of symptoms collectively called acquired immune deficiency syndrome (AIDS)

Some background information 1981

U.S. healthcare workers noticed an increase in the number of cases of Kaposi’s sarcoma & pneumonia

These observations led to what came to be known as acquired immunodeficiency syndrome (AIDS)

1983 The retrovirus human immunodeficiency

virus (HIV) was discovered as the cause of AIDS

Where did HIV come from?

A lot of different theories & conspiracy theories

Molecular studies of HIV reveal the virus probably evolved from another HIV-like virus in chimpanzees in central AfricaBelieved to have appeared in humans

between 1915-1940 • Unrecognized

HIV

There are two strains of HIVHIV-1 & HIV-2 HIV-1 is more widely distributed and

virulent

How HIV damages the immune system All viruses must find a type of cell in the

body that matches their own proteins This is why only certain body cells are

damaged by certain viruses reflected in the symptoms associated with the particular infection

• Ex: a cold virus locates the proteins on the mucus membrane cells in your nasal region and danger those cells

• Results in swelling of the area and excessive mucus production

How HIV damages the immune system

The same is true for HIV Only certain cells in the body have the

protein in their membranes that HIV recognizes

One of those cells … Is the helper T cell

• More specifically, CD4 receptors

This is the cell HIV infects

HIV is a retrovirus

HIV-RNA is reverse transcribed The product DNA is integrated into the

host genome Directs the production of new virus

particles Because the virus exists within the

infected cell, the immune system fails to eradicate it

How this affects the immune system Helper T cells communicate which cells

need to undergo the cloning process and begin antibody production

If these cells die, the communication no longer exists

Antibodies do not get produced At this stage, the individual can no longer

fight off pathogens Secondary infections ultimately take the life

of someone with AIDS

Other facts/challenges

Accumulation of mutations from viral replicationDifficult to develop a vaccine or cure

HIV has a latency periodInfection occurs, but cells remain alive Usually years after HIV infection

before the symptoms of AIDS develops

The stages of HIV infection

Figure 43.20 Immune response diminishes viral

load; however, HIV continues to replicate

Viral load rises T cells decrease Extensive loss of cell-mediated

immunity

HIV tests

Detection of HIV-1 antibodies Appear in the blood about 1-12

months after infection Called an ELISA

• Enzyme linked immunosorbent assay

Symptoms/Stages

Initial infection (primary or acute)Feels like the fluFever, headache, nausea

Chronic infectionSwollen lymph nodes

Symptoms of AIDS

Weight loss Reoccurring respiratory tract infection Skin rashes/ulcers Opportunistic infections

PneumoniaCancersHerpes

No cure

HIV cannot be cured & progression to AIDS cannot be prevented

Drugs can slow the process• Slow viral replication

ExpensiveNot available to all

• 30-40 million people have HIV/AIDS • 70% in sub-Saharan Africa

Transmission Bodily fluids

Semen, pre-ejaculate, vaginal fluid, breast milk, blood Unprotected sex

Vaginal, oral, anal Drug use

Sharing needles Breast feeding Birth (parinatal transmission) Blood transfusions

Not the case anymore – all donated blood is screened for HIV

However, this was not the case until the mid-1990s• Numerous cases of people contracting HIV from blood

transfusion

Misconceptions/Stereotypes

Originally labeled as a disease affecting homosexuals & drug abusers Back to the group of people in 1980 This initially led to some reluctance in

allocated $ for HIV research AIDS is rapidly spreading among

heterosexuals Biggest spike in African American

females

Turn and talk

Discuss the social, emotional, political and financial issues related to AIDS

Issues related to AIDS

Education Access to health care Stereotypes Employment Finances