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Why Mandatory Testing Is a Bad Idea
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13130 |
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Section : |
CURRENT ISSUES
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11 / 1987 |
2,624 Words |
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Harvey V. Fineberg and Mary E. Wilson
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The acquired immunodeficiency syndrome (AIDS) scares all of us. First recognized in 1981, AIDS has afflicted more than 40,000 Americans and many thousands more worldwide. No one who has developed AIDS has recovered from it. The disease is caused by a virus called the human immunodeficiency virus (HIV). A recalcitrant and subtle pathogen, the HIV renders the body susceptible to other infections and to some forms of cancer; it can also cause dementia. The HIV is known to be spread by sexual intercourse (genital, anal, and oral) and by blood-to-blood transmission as occurs in the sharing of needles and syringes by intravenous drug users. The virus may also be passed from an infected mother to her infant.
One of the more sinister aspects of the AIDS epidemic is the silent nature of the infection. A person who becomes infected with the HIV is then capable of transmitting it to others, yet may have no symptoms of disease for five years or even longer. The number of asymptomatic carriers of the HIV is believed to be many times the number of patients with clinical AIDS, leading to estimates of between one and two million infected persons in the United States. These symptom-free carriers are most likely concentrated in the same groups that comprise most current AIDS patients - men (and in much smaller numbers, women) exposed sexually to infected men, and drug users who share needles. While every state has reported some cases of AIDS, the largest numbers are located in the urban areas of California and New York.
The presence of infection, whether symptomatic or not, may be detected by blood tests for antibodies to the HIV. These antibodies found in blood are proteins produced in response to the antigens (which are also proteins) that are part of the virus. Other laboratory tests for detecting the presence of the HIV include cultures for the virus (growing the virus from blood or other tissues and fluids) and direct tests for the HIV antigens. Techniques used to culture the virus are tedious and expensive. Because the virus may be found in the blood intermittently or in low concentrations, a culture from an infected person may be negative. Although a valuable tool for research, culturing is not suited to general use in clinical care or screening. Tests for circulating antigen are just now becoming more widely available. Because antigen may be detected in some patients before antibodies can be found, antigen detection may be a useful supplemental test, as in screening of blood and in early diagnosis of infection. The antigen test is also much simpler than culturing for the virus, through it, too, cannot be substituted for antibody tests because HIV antigen may become undetectable during active injection.
Tests for the HIV
At this time, the two most commonly used HIV antibody tests are the enzyme immunoassay (EIA) and the Western blot. The EIA is generally used for initial screening, and the more difficult and expensive Western blot is reserved for retesting the EIA-positive sera. Compared to most medical tests, the HIV antibody tests are very accurate - more than 99 percent accuracy is currently claimed by some EIA manufacturers.
A person who is infected with the HIV is at risk of developing AIDS, a diagnosis based on clinical findings, such as infection with the opportunistic pathogen Pneumocystis carinii. Presence of a positive test for HIV antibodies (often imprecisely described as the AIDS test
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