Confronting AIDS Update 1988 (1988) / Chapter Skim
Currently Skimming:
2. HIV Infection and its Epidemiology
2. HIV Infection and its Epidemiology
Pages 33-56
The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 33... ...
In this chapter, we focus on some important aspects of the disease and the epidemic in areas in which new data have either confirmed or altered initial impressions or in which a deeper understanding of the disease has emerged. These areas include the causative agent of AIDS, the proportion of seropositive persons who will develop AIDS, HIV infection as a continuum of conditions, the modes and efficiencies of HIV transmission, and the prevalence and incidence of HIV infection and the dimensions of the epidemic in the United States (global epidemiology is discussed in Chapter 71.
|
From page 34... ...
HIV seropositivity rates in defined subpopulations of homosexual men in San Francisco and New York City and in IV drug abusers in New York City are associated with later cases of AIDS in the same groups (Curran et al., 19881. In San Francisco, these subpopulations can be further broken down by neighborhood of residence, in which the association between HIV seropositivity and AIDS is also high (Winkelstein et al., 1987b)
|
From page 35... ...
of perinatal HIV transmission from an infected mother to her infant (CDC, 1987b) and the subsequent diagnosis of AIDS in the infected infants.
|
From page 36... ...
. Data from individuals infected with HIV through blood transfusions and data from persons with hemophilia suggest that the rate of progression from HIV infection to AIDS increases with age.
|
From page 37... ...
It is more accurate to describe HIV infection as a continuum of conditions, ranging from the acute, transient, mononucleosis-like syndrome associated with seroconversion, to asymptomatic HIV infection, to symptomatic HIV infection, and, finally, to AIDS, a spectrum that encompasses a great variety of clinical symptomatology. The terms ARC and PGL do not have the precise prognostic implications they were once thought to have.
|
From page 38... ...
that might form the basis for such a terminology. MODES AND EFFICIENCIES OF HIV TRANSMISSION Epidemiological data continue to support the observation that HIV transmission is limited to sexual contact, the sharing of contaminated
|
From page 39... ...
Heterosexual Transmission It has been clearly documented that HIV infection can be transmitted from men to women and from women to men through vaginal and anal intercourse (Fischl et al., 1987; Goedert et al., 1987; Padian et al., 1987a; Peterman et al., 19884. So far, however, the heterosexual spread of the virus in the United States has been confined mainly to persons whose sexual partners acquired HIV by other means for example, by sharing contaminated needles and syringes or from blood transfusions.
|
From page 40... ...
Case-control studies have also shown that sexual activity with female prostitutes is more common among men with AIDS than among controls; African patients with AIDS also report contact with more heterosexual partners than do controls (Quinn et al., 19861. On the other hand, homosexuality and IV drug abuse do not play a major role in HIV transmission in Africa (Plot et al., 1988~.
|
From page 41... ...
This correspondence means that IV drug abusers play a pivotal role in the spread of HIV to adults through heterosexual transmission (and to infants through perinatal transmission)
|
From page 42... ...
Information on HIV transmission through the sharing of contaminated needles and syringes is hard to gather because of the illicit nature of IV drug abuse. However, several studies have shown that once HIV is introduced into a community, its spread is rapid among IV drug abusers and a majority of them soon becomes infected (Novick et al., 1986; Robertson et al., 1986; Des Jarlais et al., 1988~.
|
From page 43... ...
Studies of the male sex partners of female IV drug abusers found similarly large risks of infection, although the numbers of male partners tested were small. In these studies, HIV transmission by the sharing of contaminated needles and syringes cannot be ruled out.
|
From page 44... ...
In this study, the best predictor of HIV transmission was the absolute number of T-helper lymphocytes in the hemophiliacs, suggesting that, as their immune systems became more suppressed, they were more likely to infect their sex partners, regardless of the frequency of sexual contact or the duration of their infection (Goedert et al., 1987~. Another finding from the investigation of spouses of transfusioninfected persons was a higher rate of transmission from men to women than from women to men.
|
From page 45... ...
Studies of infected IV drug abusers also report high rates of infection for this group, suggesting that the sharing of contaminated needles and syringes combined with frequent injections carries a high risk of infection. The sexual partners of IV drug abusers have a greater risk of becoming infected than the sexual partners of individuals who were infected by other routes, suggesting that the mode of transmission may be either heterosexual transmission or the unacknowledged sharing of contaminated needles and syringes.
|
From page 46... ...
Yet the data probably overestimate the true prevalence of HIV infection in this group because most of the respondents to these surveys were persons who were either seeking medical attention for STDs or who were concerned that their past or present sexual behavior had placed them at risk (Curran et al., 19881. The populations of IV drug abusers appear to be less mobile than the population of homosexual men, as larger differences in HIV prevalence are reported by geographic area.
|
From page 47... ...
Seropositivity is higher in black and Hispanic prostitutes than in white prostitutes. The differences in prevalence appear to be related to the extent of IV drug abuse in the groups tested and the background HIV prevalence in IV drug abusers in the area (CDC, 1987b)
|
From page 48... ...
To avoid the self-selection bias associated with volunteer programs, anonymous HIV antibody testing has also recently begun on selected hospital patients (excluding AIDS cases and other conditions related to HIV infection) at sentinel hospitals.
|
From page 49... ...
National Estimates of HIV Infection In 1986, CDC estimated the size of various segments of the population that were known to be infected (i.e., male homosexuals, IV drug abusers, hemophiliacs, heterosexuals with no known risks) , as well as the prevalence of HIV infection for each of these groups.
|
From page 50... ...
The Program of HIV Surveys and Studies CDC has responded to the urgent need to monitor the spread of HIV infection by instituting a series of seroprevalence studies and surveillance systems (Dondero et al., 19881. In approximately 30 metropolitan areas in the United States, blood samples will be routinely collected from persons treated at STD clinics, drug abuse treatment centers, family planning and women's health clinics, and tuberculosis clinics, as well as from selected hospital admissions and newborns.
|
From page 51... ...
Since the publication of Confronting AIDS, the distribution of cases by risk group as well as by sex, race, age, and geographic area has not changed substantially: 63 percent of cases are homosexual or bisexual men not known to have abused IV drugs, 19 percent are heterosexual IV drug abusers, 7 percent are both male homosexuals and IV drug abusers, 1 percent are patients with hemophilia and related disorders, 4 percent are persons who acquired the disease through heterosexual contact, 3 percent are recipients of blood transfusions, and 3 percent are cases in which risk information is undetermined because it is incomplete (patients have died, refused to be interviewed, or have been lost to follow-up) or the patients are still under investigation.
|
From page 52... ...
, mainly as a result of higher HIV prevalence in black and Hispanic IV drug abusers and their sex partners and offspring. Recent data also suggest that the virus is spreading more rapidly among blacks and Hispanics at risk than among other population groups, especially in Northeastern cities, suggesting that the future composition of AIDS cases will consist primarily of poor, urban minorities.
|
From page 53... ...
1988d. Update: Acquired immunodeficiency syndrome and human immunodeficiency virus infection among health-care workers.
|
From page 54... ...
1987. Natural history of human immunodeficiency virus infections in hemophiliacs: Effects of T-cell subsets, platelet counts, and age.
|
From page 55... ...
1987. Risk factors for infection with human immunodeficiency virus among intravenous drug abusers in New York City.
|
From page 56... ...
1987. Risk of human immunodeficiency virus infection from blood donors who later developed the acquired immunodeficiency syndrome.
|
Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.