Biology (Mader), 10th Edition

Chapter 20: Viruses, Bacteria, and Archaea

Treatment of HIV Infection

Why are viral diseases hard to treat? Viruses cause millions of people to get sick each year. In contrast the importance of bacterial diseases declined greatly after the discovery of antibiotics in the early 20th century. Why are bacterial diseases more susceptible to treatment than viral diseases? Bacteria are cellular organisms with complex metabolic pathways. They need many different molecules in order to survive and reproduce. Bacteria are also prokaryotes with a radically different cellular structure compared to human cells. Antibiotics are drugs that interfere with the cellular processes of prokaryotes but do not affect eukaryotic cells. In contrast, viruses are not composed of cells and have no metabolism to disrupt. Most treatments for viral diseases are aimed at reducing symptoms until the disease passes. The human immune system is effective against viruses and therefore it is often possible to develop vaccines. Some viruses such as those causing influenza and HIV mutate and evolve rapidly. Vaccines are generally not effective against rapidly evolving viruses.

View the animation below, then complete the quiz to test your knowledge of the concept.



1.

The drug AZT
A)inhibits the enzyme reverse transcriptase.
B)inhibits the production of HIV proteins.
C)inhibits the enzyme protease.
D)breaks down human cell receptors so that HIV cannot bind to them.
E)binds to human cell receptors thereby blocking HIV’s access to them.
2.

Chemokines appear to inhibit HIV infection by
A)blocking replication of the virus.
B)interfering with the synthesis of viral proteins.
C)interfering with the cleavage of viral polyproteins.
D)disabling the CD4 receptor.
E)blocking the CXCR4 and CCR5 coreceptors.
3.

An antiviral factor called ________ has been found in ________ cells.
A)CAF ; CD4
B)CAF ; CD8
C)NEF ; CD4
D)NEF ; CD8
E)NEF ; brain
4.

Mutations that inactivate the CCR5 receptor make an individual more susceptible to AIDS.
A)True
B)False
5.

It is hard to create a vaccine against HIV infection because the virus has a high mutation rate.
A)True
B)False
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