Human Reproduction Problem Set

Problem 7: High-risk sexual partners in terms of HIV exposure

Tutorial to help answer the question

Who of the following would be considered a "risky partner" for heterosexual sex in terms of risk for HIV infection?


A. One who has had sex with multiple partners within the past 5 years
The greater the number of sexual partners one has, the greater the probability of having sex with an infected partner and, as a result, of becoming infected with HIV. Women are at particular risk of being infected by HIV. In the United States, the percentage of adolescent women infected by HIV jumped from 19% of cases in 1987 to 39% in 1996.
A case of sexual roulette
In Arizona, about 1 in 500 college students is HIV positive. If a hypothetical, promiscuous college student were to have 5 different sexual partners for each of 5 years in college, there is 1 chance in 20 (5% odds) of having sex with an HIV positive individual. The lowest risk sexual relations occur within a long-term monogamous relationship between two people who are known to be free of HIV.

B. An individual who is HIV positive.
HIV positive individuals definitely make risky partners. However, it is very difficult to know whether a potential partner is HIV positive. Many HIV positive people show no signs of disease. Even a recent negative result for an HIV test may not be entirely reliable because a recently infected individual would likely test negative.
C. An intravenous drug user
The drug itself is not responsible for the HIV transmission; the sharing of needles and syringes is. People share needles for all sorts of reasons like steroids, diabetes, allergies, etc. Everyone but the first user of the equipment is at risk of being infected with viruses from all those who used it before. The possibility that an intravenous drug user who shares needles might be infected with HIV is very high.

The rate of new infection has been successfully controlled in some countries and certain areas in the United States where health officials use measures such as the distribution of clean hypodermic needles, more drug treatment programs, and explicit sex education.

D. A hemophiliac who has not been tested for HIV
It is estimated that as many as 30,000 Americans became HIV-infected from contaminated blood products before all FDA regulations on the testing of blood products were enforced.
E. All of the above
In addition to the risky partners mentioned above, other risk groups would include recipients of transplants or transfusions. Like hemophiliacs these people are at risk of being infected by untested or poorly tested blood products used for their transfusions.
AIDS, the disease
AIDS is a disease of the immune system caused by human immunodeficiency virus (HIV). This retrovirus reproduces at a very high rate and ultimately overcomes the ability of the immune system to respond. AIDS results when the immune system is significantly weakened and opportunistic infections begin.

Direct exchange of bodily fluids is needed for the AIDS virus to be passed on from one person to another. Direct exchange takes place through sexual relations or through the sharing of needles. Blood transfusion or injury may also expose one to the blood of an infected person. Infected mothers may transmit the virus to their unborn child or at birth and through breast feeding. HIV is not an airborne virus and cannot be transmitted by casual contacts.

HIV infected
Worldwide, an estimated 30 million people are infected with HIV. By the year 2000, the number of people infected is expected to reach 40 million. In the United States, AIDS is presently the number one killer for individuals between the ages of 25 and 44. About a million American men, women, and children have been diagnosed as HIV-positive. For many, such a diagnosis is an automatic death sentence.

Although new medications are promising, not everyone can tolerate the side effects of the drug treatments and no one knows how long the positive effects that have been observed will last. Furthermore, the high cost of the treatment is prohibitive to a large segment of the population, especially for those living in the developing world. Education and safe sex are still the most important factors in controlling the spread of HIV. AIDS is not a curable disease, but we can start thinking of it as a chronic disease instead of considering it a death sentence.

Please see the tutorial on HIV and AIDS for more information.

The Biology Project
University of Arizona
Updated: July 15, 1999
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