HIV 15: Additional HIV references

Date: 22 Feb 1996 11:22:11 GMT
From: "James 2 Ryan" 
Subject: Additional HIV references
To: gtf@math.rochester.edu
Comment: Memo - Internet 02-22-96 11:14:26

Abstract

Anton Breinl Centre for Tropical Health and Medicine, James Cook University, Townsville, Queensland, Australia

BACKGROUND. Mathematical models of the AIDS epidemic have not been able to give accurate predictions about the size of the epidemic because it is not possible to obtain sufficiently accurate measurements of the factors that enable HIV transmission. The uncertainties inherent in models of the AIDS epidemic appear to limit their relevance to epidemiologists. However, it is shown here that the uncertainties need not prevent models being used to make reliable decisions about which preventive strategy will be most effective.

METHOD. A range of strategies are simulated in a model of the AIDS epidemic. The simulations are repeated as the value of what seems to be the most important uncertain factor, is varied. The effect of this variation on the effectiveness of each strategy is noted. In principle, the process could be repeated whilst all other uncertain factors are varied as well.

RESULTS. Although varying one uncertain factor created enormous variation in the size of the epidemic, it is remarkable that for most preventive strategies the relative effectiveness of the strategies was barely altered. Hence for the most part the ranking of strategies in order of effectiveness is not affected by the area of uncertainty explored here. The results also highlight the potential effectiveness not only of general condom promotion, but also the use of circumcision and spermicides and general screening or targetted screening in sexually transmitted disease clinics.

CONCLUSIONS. Epidemiological modelling may accurately rank the effectiveness of interventions although it may fail to predict the size of the epidemic.

Abstract

Kenya Medical Research Institute, Nairobi, Kenya

A total number of two hundred eighty three long distance truck drivers and their assistants (loaders) who ferry goods between Kenya and Zaire were included in a cross-sectional study between September 1991 and April 1992. Twenty six percent of the study subjects were seropositive for HIV-1 and none were HIV-2 seropositive. Countries of birth and residence were significantly associated with HIV infection (X2 = 23.6, P = 0.0006). Significant associations were also found between HIV seropositivity and level of education from secondary school and above (OR = 3.4, 95% C.I. = 1.01-11.55); being circumcised was more protective, (OR = 0.38; 95% C.I. = 0.19-0.76), history of many years of driving (X2 = 9.3, p = 0.0254) and income (OR = 11.13, 95% C.I. = 1.35-91.95). When a stepwise multiple logistic regression model was fitted to all the variables observed to be significant in the univariate analysis, the following risk factors attained statistical significance: lack of circumcision (OR = 3.75); income greater than Ksh. 2000 (OR = 7.24); being employed in long distance driving more than 11 years (OR = 3.98); and secondary school education and above (OR = 4.06, 95% C.I. = 1.18-13.98). Reference for all the above Odds Ratios was 1.

Abstract

Department of Medical Microbiology, University of Nairobi, Kenya

BACKGROUND: A cross-sectional survey was performed to determine the seroprevalence and correlates of human immunodeficiency virus (HIV) infection among long-distance truck drivers in Kenya.

METHODS: Truck drivers along the Mombasa-Nairobi highway were enrolled at a roadside research clinic. A standardized interview and serologic evaluation for HIV and syphilis were conducted.

RESULTS: We enrolled 970 truck drivers and their assistants of whom 257 (27%) had HIV antibodies. In univariate analysis, HIV infection was correlated with older age, non-Kenyan nationality, Christian religion, longer duration of truck driving, travel outside of Kenya, less frequent visits to wives, and more frequent visits to prostitutes. Uncircumcised status, history of genital ulcer disease or urethritis during the previous 5 years, and a positive Treponema pallidum hemagglutination assay for syphilis were each associated with positive HIV serostatus. Univariate correlates of uncircumcised status included younger age, non-Kenyan nationality, Christian religion, travel outside of Kenya, and less frequent visits to prostitutes. There was a significant association between uncircumcised status and 5-year history of genital ulcer disease or serologic evidence of syphilis, but not with 5-year history of urethritis. In multivariate analysis, HIV infection was independently associated with uncircumcised status (adjusted odds ratio [OR], 4.9; 95% confidence interval [CI], 2.8 to 8.4), history of genital ulcer disease (adjusted OR, 2.4; 95% CI, 1.5 to 4.1), history of urethritis (adjusted OR, 1.8; 95% CI, 1.1 to 2.9), more frequent sex with prostitutes (more than once per month; adjusted OR, 1.7; 95% CI, 1.1 to 2.8), and positive T pallidum hemagglutination assay (adjusted OR, 1.2; 95% CI, 1.0 to 1.4). The attributable risk percentage for the association between HIV and uncircumcised status was 70%, and the population attributable risk was 25%.

CONCLUSIONS: Truck drivers in east Africa are at high risk of HIV infection. The strongest correlates of HIV seropositivity were uncircumcised status and history of both ulcerative and nonulcerative sexually transmitted diseases.

Abstract

Department of Epidemiology, Harvard School of Public Health, Boston, MA 02115

OBJECTIVE: To study risk factors for HIV infection among women in Nairobi, Kenya, as the epidemic moves beyond high-risk groups.

DESIGN: A cross-sectional case-control study among women attending two peri-urban family planning clinics.

METHODS: A total of 4404 women were enrolled after giving written informed consent. Information on risk factors was obtained by interview using a structured questionnaire. Blood was taken for HIV and syphilis testing, and genital specimens for gonorrhea and trichomoniasis screening.

RESULTS: Two hundred and sixteen women (4.9%; 95% confidence interval, 4.3-5.5) were HIV-1-positive. Although risk of HIV was significantly increased among unmarried women and among women with multiple sex partners, most seropositive women were married and reported only a single sex partner in the last year. Women with a history or current evidence of sexually transmitted disease were at significantly increased risk; however, the prevalence of these exposures was low. Women whose husband or usual sex partner was uncircumcised had a threefold increase in risk of HIV, and this risk was present in almost all strata of potential confounding factors. Only 5.2% of women reported ever having used a condom.

CONCLUSIONS: These data suggest that, among women who are not in high-risk groups, risk of HIV infection is largely determined by their male partner\'s behavior and circumcision status. Interventions designed to change male sexual behavior are urgently needed.

Abstract

Medical Research Council (UK) Programme on AIDS in Uganda, Entebbe

OBJECTIVE: To study in depth sexual history and sexual behaviour variables as risk factors for HIV-1 infection in a rural Ugandan population.

METHODS: Following a socioeconomic and serological survey of a rural population in Masaka District, south-west Uganda, 233 randomly selected HIV-1-positive cases and 233 negative controls matched on age and village of residence, were invited in October 1990 to participate in a case-control study. A total of 132 cases and 161 controls attended for in-depth investigation including an interview about sexual behaviour.

RESULTS: The factor most strongly associated with increased risk of infection was a greater number of lifetime sexual partners, with odds ratios (OR) of 2.1 and 4.9 for those reporting 4-10 and 11 or more partners, respectively, compared with those reporting less than four partners. Having only one sexual partner did not provide complete protection, a total of seven (one male, six female) subjects reporting only one sexual partner were HIV-1-positive. Other significant factors were a history of genital ulcers [OR, 2.9; 95% confidence intervals (CI), 1.0-9.1) and not being a Muslim (OR, 5.4; 95% CI, 1.8-16.5) suggesting a possible protective effect of circumcision. There was a suggestion that those who married within the last 7 years (OR, 2.4; 95% CI, 0.9-6.1) and men exposed to menstrual blood (OR, 5.7; 95% CI, 0.7-49.8) were atan increased risk of HIV-1 infection.

CONCLUSIONS: These results confirm the predominant role of sexual behaviour in the HIV-1 epidemic. Of particular concern is the observation of HIV-1 infection among those reporting only one partner. Where HIV-1 infection is widely distributed in the general population, risk reduction strategies should, in addition to the promotion of partner reduction, place strong emphasis on safe-sex techniques.

Abstract

Department of Community Health, University of Nairobi,Kenya

BACKGROUND AND OBJECTIVES: Whether male circumcision reduces the risk of acquiring human immunodeficiency virus (HIV) infection remains controversial.

STUDY DESIGN: As there have now been a number of studies conducted that have examined this issue, we undertook to review their findings. Thirty epidemiological studies identified in the literature that investigated the association between male circumcision status and risk for HIV infection were reviewed.

RESULTS: Eighteen cross-sectional studies from six countries reported a statistically significant association, four studies from four countries found a trend toward an association. Four studies from two countries found no association. Two prospective studies reported significant associations, as did two ecological studies. In studies in which significant associations were demonstrated, measures of increased risk ranged from 1.5 to 8.4. The groups in which positive associations were found included sexually transmitted disease (STD) clinic and hospital patients, outpatient clinic and HIV screening clinic attenders, long-distance truck drivers, and general community members.

CONCLUSION: Potential sources of error, assessment of caus ality, impli cations of the findings, and future research needs are discussed. Because a substantial body of evidence links noncircumcision in men with risk for HIV infection, consideration should be given to male circumcision as an intervention to reduce HIV transmission.

Abstract

Department of Epidemiology, Harvard School of Public Health, Boston, MA 02115

As the epidemic of the acquired immunodeficiency syndrome (AIDS) in sub-Saharan Africa enters its second decade, much has been learned about the distribution and determinants of the disease and its causative agent, the human immunodeficiency virus (HIV). Over 6 million people, or 2.5% of the adult population, are thought to be infected with HIV. The distribution of HIV is largely determined by sexual behavior; as for other sexually transmitted diseases, the characteristics of sexual networks determine the extent and rate of spread of HIV. Female sex workers and their male clients are at high risk for HIV and have been important in initiating the epidemic in many African countries. The dynamics of HIV in the rest of the population are complex; men with multiple sexual partners are largely responsible for transmission of HIV to women in the general population. Other sexually transmitted diseases and lack of male circumcision may increase the probability of transmission of HIV during sexual intercourse and probably are partially responsible for the rapid diffusion of HIV in Africa. Interventions among high-risk groups are needed, but they must be accompanied by attempts to induce behavior change among men and women in the general population. Epidemiologic studies of the determinants of sexual behavior and sexual contact patterns, as well the design and evaluation of interventions, are urgently needed. Key areas for development are the study of behavioral exposures and outcomes, the evaluation of interventions, developing new methods for conducting interventions in resource-poor environments, and increasing the number of African scientists with the skills and resources to conduct epidemiologicstudies.

Abstract

Department of Epidemiology, University of Washington, Seattle

To evaluate whether uncircumcised status is correlated with acquisition of human immunodeficiency virus (HIV), 502 homosexual men were surveyed; 85% were circumcised. HIV infection was significantly associated with uncircumcised status (odds ratio [OR], 2.2; 95% confidence interval [CI], 1.2, 3.8), nonwhite race, intravenous drug use, sexual contact with an intravenous drug user, number of male partners, frequency of unprotected receptive anal intercourse, and with history of genital herpes, anal herpes, or syphilis. Uncircumcised status was significantly associated with older age, nonwhite race, and history of syphilis; it was inversely associated with intravenous drug use. Using logistic regression analysis, the adjusted OR for the association between HIV infection and uncircumcised status was 2.0 (95% CI, 1.0, 4.0). Uncircumcised homosexual men had 2-fold increased risk of HIV infection. The role of circumcision as an intervention strategy to reduce sexual transmission of HIV warrants consideration.

Abstract

Projet RETRO-CI, Institut d\'Hygiene, Treichville

OBJECTIVE: (1) To determine the prevalence of HIV-1 and HIV-2 infections and associated risk factors in men attending Abidjan\'s three sexually transmitted disease (STD) clinics; (2) to examine the use of such sites for epidemiological surveillance.

DESIGN: Cross-sectional study.

SETTING: Abidjan\'s two main STD clinics (Clinics A and T), and the University Hospital Dermatology outpatients clinic.

PATIENTS: Consecutive patients with genitourinary sym ptoms.

MAIN OUTCOME MEASURES: Prevalence of reactivity to HIV-1, HIV-2, and both viruses; descriptive characteristics of clinic attenders; clinical diagnoses of STD; risk factors associated with HIV-1 and HIV-2 positivity.

RESULTS: The overall prevalence of HIV (HIV-1 and/or HIV-2) infection was 21% (250 out of 1169; 16% HIV-1, 2% HIV-2, 3% dual reactivity). Overall prevalence varied by clinic: University Hospital Dermatology outpatients clinic, 39%; Clinic T, 19%; Clinic A, 10%. Men with STD had an overall prevalence of 31% (155 out of 506), compared with 14% in men without physical signs of STD (odds ratio 2.6, 95% confidence interval 2.0-3.6). The highest prevalence, 46%, was in men with genital ulcer disease. Risk factors associated with HIV-1 as well as with HIV-2 infection after multivariate analysis were a history of sex with prostitutes, lack of circumcision, being unskilled, and a history of prior genital ulcer. Current genital ulcer, current STD and positive Treponema pallidum haemagluttination assay were associated with HIV-1 and dual reactivity.

CONCLUSIONS: Risk factors for HIV-2 infection in men attending Abidjan STD clinics were broadly similar to those for HIV-1 infection. HIV-1 infection was more strongly associated with current STD. Important differences between the three clinics were observed in STD prevalence and type, and HIV seroprevalence. Such differences should be taken into account in the planning of HIV serosurveillance in STD clinics.

Abstract

Medical Research Council Laboratories, Fajara, The Gambia

OBJECTIVE: To investigate whether genital ulcer diseases are cofactors which enhance the transmission of HIV-2 in West Africa.

DESIGN: A cross-sectional study of 435 men presenting with a sexually transmitted disease (STD).

SETTING: The outpatient clinic of the Medical Research Council Laboratories, a primary care facility in Fajara, a suburb of Banjul, the capital city of The Gambia (West Africa).

PATIENTS, PARTICIPANTS: Six hundred and twenty-four men presenting with a genital complaint, of whom 443 had an STD. Eight of the men with an STD were excluded from further analysis because they were HIV-1-infected (five patients) or had indeterminate Western blot patterns (three patients). The remaining 21 HIV-2-infected and 414 seronegative men constituted our study-group.

MAIN OUTCOME MEASURES: Participants were questioned about previous STD and behavioural and demographic characteristics. A physical examination was performed and serum c ollected for measurement of antibodies against Haemophilus ducreyi and Treponema pallidum.

RESULTS: HIV-2-infected men were more likely than HIV-seronegative participants to have previously had a genital ulcer [odds ratio (OR), 3.00; 95% confidence interval (Cl), 1.18-7.60] and to have antibodies against T. pallidum (OR, 5.95; 95% Cl, 2.10-16.91), or H. ducreyi (OR, 4.59; 95% Cl, 1.71-12.33). Circumcised patients with residual foreskin were more likely to be HIV-2 infected than patients with complete circumcision. HIV-2-seropositive patients were six times more likely to have generalized lymphadenopathy than their seronegative counterparts.

CONCLUSIONS: Our data suggest that genital ulcerative diseases, such as syphilis and chancroid, are probably cofactors that increase the transmission of HIV-2 in West Africa, and that HIV-2 infection frequently results in generalized lymphadenopathy.

Abstract

Department of Medical Microbiology, College of Health Sciences, University of Nairobi

A cross section study was conducted among long distance truck drivers to determine the prevalence of sexually transmitted diseases (STDs) and antibodies to human immunodeficiency virus (HIV). A total of 8 drivers and their assistants en route from port of Mombasa to countries in East and Central Africa were enrolled into the study. Blood was taken for HIV and syphilis serology. Discharges from urethra and genita l ulcer disease (GUD) were cultured. Seroprevalence for HIV was 18% and 4.6% for syphilis. Fifty percent of Neisseria Gonorrhea cultured were penicillinase producers. Most of the men with urethral discharge and all the GUD were culture negative, probably due to prior treatment. Lack of circumcision, past history of GUD and urethritis were significantly associated with HIV seroconversion.

Abstract

University of Manitoba, Winnipeg, Canada

Epidemiologic studies in Nairobi and elsewhere in Africa, have shown that men infected with HIV-1 more commonly have a history of genital ulcer disease compared to uninfected men. In one study, HIV infected men were three times as likely to have a recent history of genital ulcers. In a prospective study of seronegative men, those presenting with chancroid had a five-fold risk of seroconversion during follow-up compared to men presenting with urethritis. Uncircumcised men had an increased risk of seroconversion which was independent of their risk of genital ulcer disease. Over 95% of attributable risk in men with STD was either genital ulceration or the presence of a foreskin. Genital ulcers are a major risk factor for HIV infection among prostitutes. The increased risk is about 10-fold among prostitutes with ulcers compared to a cohort who did not. We hypothesize from these studies that genital ulcers are the major portals of entry for HIV infection and also increased shedding of virus infected cells into the vaginal secretions. HIV seropositive prostitutes are more susceptible to chancroid with a two-fold increase in the prevalence of genital ulcers as compared to HIV negative women. The use of condoms by their clients prevents both genital ulcer disease and HIV acquisition among prostitutes. Chancroid is more difficult to treat in HIV infected men with one-third of patients failing single dose treatment regimens as compared to less than five percent of men without HIV infection.(ABSTRACT TRUNCATED AT 250 WORDS).

Abstract

Department of Medical Microbiology, University of Nairobi, Kenya

To ascertain whether male circumcision might explain some of the geographical variation in human immunodeficiency virus (HIV) seroprevalence in Africa, we investigated the association between the practice of male circumcision at a societal level and HIV seroprevalence. Male circumcision practices for over 700 African societies were identified, and HIV seroprevalence in general adult populations from 140 distinct locations in 41 countries was obtained. In locations where male circumcision is practised, HIV seroprevalence was considerably lower than in areas where it is not practised. This study supports the hypothesis that lack of circumcision in males is a risk factor forHIV transmission.

Abstract

Research Division, New York City, New York 10017

The relationship between HIV seroprevalence and the proportion of uncircumcised males in African countries is examined to determine whether circumcision practices play a role in explaining the large existing variation in the sizes of African HIV epidemics. A review of the anthropological literature yielded estimates of circumcision practices for 409 African ethnic groups from which corresponding national estimates were derived. HIV seroprevalence rates in the capital cities were used as indicators of the relative level of HIV infection of countries. The correlation between these two variables in 37 African countries was high (R = 0.9; P less than 0.001). This finding is consistent with existing clin ic-based studies that indicate a lower risk of HIV infection among circumcised males.

Abstract

Department of Medical Microbiology, University of Nairobi, Kenya

To determine the frequency and risk factors for female to male sexual transmission of human immunodeficiency virus type 1 (HIV-1), a prospective study was carried out in 422 men who had acquired a sexually transmitted disease (STD) from a group of prostitutes with a prevalence of HIV-1 infection of 85%. The initial seroprevalence of HIV among the men was 12%. 24 of 293 (8.2%) initially seronegative men seroconverted to HIV-1. Newly acquired infection was independently associated with frequent prostitute contact (risk ratio 3.2, 95% confidence interval 1.2-8.1), with the acquisition of genital ulcer disease (risk ratio 4.7, 95% confidence interval 1.3-17.0), and with being uncircumcised (risk ratio 8.2, 95% confidence interval 3.0-23.0). 96% of documented seroconversions occurred in men with one or both of the latter two risk factors. In a subgroup of 73 seronegative men who reported a single prostitute sexual contact, the frequency of HIV-1 infection was 8.2% during 12 weeks of observation. No man without a genital ulcer seroconverted. A cumulative 43% of uncircumcised men who acquired an ulcer seroconverted to HIV-1 after a single sexual exposure. These data indicate an extremely high rate of female to male transmission of HIV-1 in the presence of STD and confirm a causal relation between lack of male circumcision, genital ulcer disease, and susceptibility to HIV-1 infection.

Abstract

Department of Medicine, University of Washington, Seattle Among 115 heterosexual men who presented with genital ulcers to a sexually transmitted disease clinic in Nairobi, Kenya, the prevalence of serum antibody to HIV was 16.5%. A past history of genital ulcers was reported by 12 (63%) of 19 men with antibody to HIV versus 30 (31%) of 96 without antibody (P = 0.008). HIV infection was also positively associated with lack of circumcision, but was not associated with the etiology of the current genital ulcer. Logistic regression analysis (adjusted for age, number of recent sex partners, recent prostitute contact, circumcision, tribal ethnic identity, past history of urethritis, and current diagnoses) confirmed only the association between prior history of genital ulcer disease and HIV infection; (P = 0.04, odds ratio 2.35, 95% confidence limits, 1.01-5.47). The incidence of genital ulcers, particularly chancroid, is much higher in parts of Africa than in Europe or North America. This may contribute to the increased risk of heterosexual transmission of HIV in Africa. Aggressive control of chancroid and syphilis may offer one very feasible approach to reducing transmission of HIV in this region.

Abstract

Department of Medical Microbiology, University of Nairobi, Kenya Heterosexual transmission of the human immunodeficiency virus (HIV) appears to occur readily in Africa but less commonly in North America and Europe. We conducted a case-control study among men attending a clinic for sexually transmitted diseases in Nairobi to determine the prevalence of HIV infection and the risk factors involved. HIV antibody was detected in 11.2 percent of 340 men who enrolled in the study. Reports of nonvaginal heterosexual intercourse and homosexuality were notably rare. Recent injections and blood transfusions were not associated with HIV infection. Travel and frequent contact with prostitutes were associated with HIV seropositivity. Men who were uncircumcised were more likely to have HIV infection (odds ratio, 2.7; P = 0.003), as were those who reported a history of genital ulcers (odds ratio, 7.2; P less than 0.001). A current diagnosis of genital ulcers was also associated with HIV seropositivity (odds ratio, 2.0; P = 0.028). Multivariate analysis revealed an independent association of genital ulcers with HIV infection in both circumcised and uncircumcised men. Uncircumcised men were more frequently infected with HIV, regardless of a history of genital ulcers. Our study finds that genital ulcers and an intact foreskin are associated with HIV infection in men with a sexually transmitted disease. Genital ulcers may increase men\'s susceptibility to HIV, or they may increase the infectivity of women infected with HIV. The intact foreskin may operate to increase the susceptibility to HIV.