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