The following sections of this BookRags Literature Study Guide is offprint from Gale's For Students Series: Presenting Analysis, Context, and Criticism on Commonly Studied Works: Introduction, Author Biography, Plot Summary, Characters, Themes, Style, Historical Context, Critical Overview, Criticism and Critical Essays, Media Adaptations, Topics for Further Study, Compare & Contrast, What Do I Read Next?, For Further Study, and Sources.
(c)1998-2002; (c)2002 by Gale. Gale is an imprint of The Gale Group, Inc., a division of Thomson Learning, Inc. Gale and Design and Thomson Learning are trademarks used herein under license.
The following sections, if they exist, are offprint from Beacham's Encyclopedia of Popular Fiction: "Social Concerns", "Thematic Overview", "Techniques", "Literary Precedents", "Key Questions", "Related Titles", "Adaptations", "Related Web Sites". (c)1994-2005, by Walton Beacham.
The following sections, if they exist, are offprint from Beacham's Guide to Literature for Young Adults: "About the Author", "Overview", "Setting", "Literary Qualities", "Social Sensitivity", "Topics for Discussion", "Ideas for Reports and Papers". (c)1994-2005, by Walton Beacham.
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Latency refers to the period of time it takes for a disease to manifest itself within the human body. It is the state of seeming inactivity that occurs between the instant of stimulation or initiating event and the beginning of response. The latency period differs dramatically for each stimulation and as a result, each disease has its unique time period before symptoms occur.
When pathogens gain entry into a potential host, the body may fail to maintain adequate immunity and thus permits progressive viral or bacterial multiplication. This time lapse is also known as the incubation period. Each disease has definite, characteristic limits for a given host. During the incubation period, dissemination of the pathogen takes place and leads to the inoculation of a preferred or target organ. Proliferation of the pathogen, either in a target organ or throughout the body, then creates an infectious disease.
Botulism, tetanus, gonorrhea, diphtheria, staphylococcal and streptococcal disease, pneumonia, and tuberculosis are among the diseases that take varied periods of time before the symptoms are evident. In the case of the childhood diseases—measles, mumps, and chicken pox—the incubation period is 14–21 days.
In the case of cancer, the latency period for a small group of transformed cells to result in a tumor large enough to be detected is usually 10–20 years. One theory postulates that every cancer begins with a single cell or small group of cells. The cells are transformed and begin to divide. Twenty years of cell division ultimately results in a detectible tumor. It is theorized that very low doses of a carcinogen could be sufficient to transform one cell into a cancerous tumor.
In the case of AIDS, an eight- to eleven-year latency period passes before the symptoms appear in adults. The length of this latency period depends upon the strength of the person's immune system. If a person suspects he or she has been infected, early blood tests showing HIV antibodies or antigens can indicate the infection within three months of the stimulation. The three-month period before the appearance of HIV antibodies or antigens is called the "window period."
In many cases, doctors may fail to diagnose the disease at first, since AIDS symptoms are so general they may be confused with the symptoms of other, similar diseases. Childhood AIDS symptoms appear more quickly since young children have immune systems that are less fully developed.