Portrait of a Killer
Depending upon students' grade and maturity levels, the essay, ”The Deadly Cycle," may be used as teacher background information or as a student reading assignment. It is especially effective when read aloud.
Imagine you are a doctor…
A young man arrives at your hospital in a very weak, deteriorated condition. His body resembles that of a concentration camp survivor. After running a few tests, you determine the patient is suffering from pneumocystis pneumonia, a very rare lung infection, especially in people with healthy immune systems. As a doctor, you refer to the infection as PCP. Over the coming weeks, several more patients arrive at your hospital, suffering from the same condition. All eventually die. You infer that every recent PCP patient had a weakened immune system.
A cluster of patients with the same rare condition raises a medical “red flag.” Something new may be happening.
Across the country, other doctors encounter larger than the usual numbers of PCP patients, and other people with a different rare disease, Kaposi’s sarcoma (or KS). KS is a form of cancer. It causes purple, red, brown and black skin lesions (sores) to appear over the entire body and in the mouth. The lesions are painful and disfiguring. They make eating difficult, and often are accompanied by unrelenting headaches. Ultimately, the KS patients die. Like PCP, Kaposi’s sarcoma is exceedingly rare in people with healthy immune systems. Doctors treating KS patients infer that these people had weakened immune systems.
This really happened. The first recognized cases of the syndrome we today call AIDS, or acquired immunodeficiency syndrome, appeared in homosexual men in California in 1981. Soon after, similar clusters of AIDS cases occurred in New York. Then, men and women of Haitian origin began checking into Miami hospitals with symptoms of both PCP and KS. They, too, had AIDS, which was spreading across the country. It is estimated that by the time of its discovery, the new virus called HIV already had infected hundreds of thousands of men, women and children in the United States, and millions more people around the world.
What is HIV?
In the strictest sense, HIV, the Human Immunodeficiency Virus, is not a life form. Until it invades a human host, it’s just a protein-coated mass of genetic material, no more alive than a grain of sand. Under a microscope, HIV appears insignificant, approximately 120 times smaller than the white blood cells it invades. But it is frighteningly powerful. Once inside a cell, HIV’s genetic material serves as a biological “how-to” manual. The virus replicates itself hundreds of thousands of times, until the cell can no longer contain all the individual viruses. The new viruses push out, or “bud,” through the cell wall. In the process, they steal part of the cell’s outer envelope (cell membrane), which they use to create an outer protective layer.
Over a period of years, new HIV copies spread through the host body to infect more and more cells.
Gradually, the body’s white blood cells, the “backbone” of a person’s immune system, are destroyed. When the immune system is working, it attacks and fights off invading diseases. But when it is weakened or destroyed, it can no longer protect the body. Ultimately, HIV infection leads to a condition called AIDS, or acquired immunodeficiency syndrome. Untreated, AIDS opens the body to progressively rare and devastating illnesses until death results.
- Vogt, G., and Moreno, N. (2012) The Science of HIV/AIDS Teacher’s Guide. Baylor College of Medicine: Houston. ISBN: 978-1-888997-62-0
- Transmission electron microscopic image courtesy of Charles P. Daghlian, Ph.D., and Louisa Howard © Dartmouth College.
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Grant Number: 5R25RR018605