The spread of HIV-1 in Africa: sexual contact patterns and the predicted demographic impact of AIDS

Article Abstract:

Even today, AIDS is the leading cause of death among adults in some urban centers in Africa. All the available evidence indicates that the impact of AIDS on the African continent will be devastating. Providing more detailed predictions of the course of the AIDS epidemic turns out to be quite difficult. Accurate data on the prevalence of HIV (human immunodeficiency virus) infection, which causes AIDS, is often not available. Furthermore, the most common mode of transmission in Africa is different from that in most developed countries. While in developed countries like the United States, most new transmissions are among intravenous drug users, heterosexual contact appears to be the primary means of HIV transmission among adults in Africa. This may be due to a longer duration of the epidemic on that continent. Unfortunately, much less is known about heterosexual transmission of the AIDS virus. There is some indication that the increased prevalence of other sexually transmitted diseases makes the transmission of HIV more likely. It has also been suggested that higher rates of changing sexual partners are partially responsible for the AIDS epidemic in Africa, but solid evidence to support this theory is lacking. The combination of inadequate prevalence information and a poor understanding of HIV transmission is responsible for much of the difficulty in prediction. Researchers have developed a set of mathematical models which indicate the future of AIDS in Africa under different sets of parameters. In all cases, the impact of AIDS will be disastrous. However, under some scenarios, the rate of death from AIDS will surpass the birth rate. It is possible that in one or two decades the population of Africa will begin to decrease under the onslaught of AIDS. It is not possible to determine which of the mathematical models most closely resembles the sequence of events that will actually unfold. However, the construction of such models is important to demonstrate to world leaders the possibilities they may face in several decades. There is a strong tendency to deal with the most immediate problems resulting from the AIDS epidemic. Leaders must see the importance of instituting changes to slow the rate of infection rather than merely deal with the cases of AIDS which already exist. (Consumer Summary produced by Reliance Medical Information, Inc.)

Health aspects, Sexual behavior, Africa, Sex customs

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Potential of community-wide chemotherapy or immunotherapy to control the spread of HIV-1

Article Abstract:

Mathematical models show that if individuals infected with the human immunodeficiency virus (HIV) are treated with antiviral drugs, such as zidovudine or immunotherapy (products of the immune system), treatment may actually increase the spread of HIV and the number of AIDS cases. (HIV infection causes AIDS.) This may occur because zidovudine prolongs the lives of those who are infected, but does not cure them. Consequently, there is a longer period of time during which those with HIV infection can transmit the disease to others. This model is based on the premises that the rate of HIV transmission is not significantly reduced with treatment and that counselling, which is a part of treatment, does not necessarily lead to the use of safer sex practices or safer use of illicit drugs. The mathematical studies indicate that the number of AIDS cases may increase after treatment when the transmission rates are low, treatment lengthens the incubation period by only a few years, and the number of HIV-infected people being treated is small. Although this study was based on the homosexual population, the findings may apply to the heterosexual population as well. The results show that where transmission rates are high, such as in communities using intravenous drugs, treatment would be beneficial for HIV-infected individuals and the community-at-large. It is hoped that this study will emphasize the need for effective counselling to reduce the rate of HIV transmission and that further studies will be conducted to determine whether infectivity is reduced with zidovudine treatment. (Consumer Summary produced by Reliance Medical Information, Inc.)

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AIDS: Will therapy spread disease?

Article Abstract:

Although there is no cure for AIDS, and no vaccine available to prevent it, treatment with the drug zidovudine prolongs the lives of those who have developed the disease. It is possible that treatment of individuals infected with the human immunodeficiency virus (HIV), which causes AIDS, will increase the incidence (number of new cases) of HIV infection. Treatment and longer life allows greater time for those who are infected with HIV to transmit the virus to others. The benefits of treatment for the community at large are questioned. Mathematical studies have shown that the number of AIDS cases may increase when HIV transmission rates are low, treatment lengthens the incubation period by only a few years, and the number of HIV- infected people being treated is small. This model is based on the facts that the infection rate is not significantly reduced with treatment and that counselling does not necessarily lead to the use of safer sex practices or safer use of illicit drugs. Little is known about the rate of HIV infection after an individual is treated with zidovudine. However, it is felt that the behavior of individuals, especially homosexual men, has changed. In many Third World countries, such as Africa, where the AIDS epidemic is wide-spread, zidovudine is not available for treatment. Under these circumstances, there is no need to be concerned if treatment will increase the spread of disease. (Consumer Summary produced by Reliance Medical Information, Inc.)

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