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Probability of HIV-1 Transmission per Coital Act in Monogamous, Heterosexual, HIV-1-Discordant Couples in Rakai, Uganda
Abstract
The probability of HIV-1 transmission per coital act in representative African populations is unknown. We aimed to calculate this probability overall, and to estimate how it is affected by various factors thought to influence infectivity.
174 monogamous couples, in which one partner was HIV-1 positive, were retrospectively identified from a population cohort in Rakai, Uganda. Frequency of intercourse and reliability of reporting within couples was assessed prospectively. HIV-1 seroconversion was determined in the uninfected partners, and HIV-1 viral load was measured in the infected partners. Adjusted rate ratios of transmission per coital act were estimated by Poisson regression. Probabilities of transmission per act were estimated by log-log binomial regression for quartiles of age and HIV-1 viral load, and for symptoms or diagnoses of sexually transmitted diseases (STDs) in the HIV-1-infected partners.
The mean frequency of intercourse was 8.9 per month, which declined with age and HIV-1 viral load. Members of couples reported similar frequencies of intercourse. The overall unadjusted probability of HIV-1 transmission per coital act was 0.0011 (95% CI 0.0008-0.0015). Transmission probabilities increased from 0.0001 per act at viral loads of less than 1700 copies/mL to 0.0023 per act at 38 500 copies/mL or more (p=0.002), and were 0.0041 with genital ulceration versus 0.0011 without (p=0.02). Transmission probabilities per act did not differ significantly by HIV-1 subtypes A and D, sex, STDs, or symptoms of discharge or dysuria in the HIV-1-positive partner.
Higher viral load and genital ulceration are the main determinants of HIV-1 transmission per coital act in this Ugandan population.
... During this stage, a host protease called furin cleaves the precursor membrane (prM) protein from the E protein facilitating the formation of mature infectious virions. Finally, by the process of endocytosis the mature virions are released from the infected host, completing the viral replication cycle & enabling the dissemination of the virus to new susceptible cell or host [32]. ...
... Exposure to the semen or mucosal surface were the most common route of HIV transmission. However, as reported, the probability of HIV transmission was only 0.01%-0.4% per sexual contact [6], suggesting that HIV infection also depends on the interaction between the virus and host. Host immune activation might facilitate HIV transmission and infection. ...
Background
The causal association between gut microbiome and HIV infection remains to be elucidated. We conducted a two-sample mendelian randomization analysis to estimate the causality between gut microbiome and HIV infection.
Methods
Publicly released genome-wide association studies summary data were collected to perform the mendelian analysis. The GWAS summary data of gut microbiome was retrieved from the MiBioGen consortium, which contains 18 340 samples from 24 cohorts. GWAS summary data of HIV infection was collected from the R5 release of FinnGen consortium, including 357 HIV infected cases and 218 435 controls. The SNPs were selected as instrumental variables according to our selection rules. And SNPs with a F-statistics less than ten were regarded as weak instrumental variables and excluded. Mendelian randomization analysis was conducted by five methods, including inverse variance weighted (IVW), MR-Egger, weighted median, weighted mode, and simple mode. The Cochran’s Q test and MR-Egger intercept test were performed to identify heterogeneity and pleiotropy. Leave-one-out analysis were used to test the sensitivity of the results.
Results
Fifteen gut microbiota taxa showed causal effects on HIV infection according to the MR methods. Four taxa were observed to increase the risk of HIV infection, including Ruminococcaceae (OR: 2.468[1.043, 5.842], P: 0.039), RuminococcaceaeUCG005 (OR: 2.051[1.048, 4.011], P: 0.036), Subdoligranulum (OR: 3.957[1.762, 8.887], P < 0.001) and Victivallis (OR: 1.605[1.012, 2.547], P=0.044). Erysipelotrichaceae was protective factor of HIV infection (OR: 0.278[0.106, 0.731], P < 0.001) and Methanobrevibacter was also found to be associated with reduced risk of HIV infection (OR: 0.509[0.265, 0.980], P=0.043). Horizontal pleiotropy was found for Fusicatenibacter (P<0.05) according to the MR-Egger regression intercept analysis. No heterogeneity was detected.
Conclusion
Our results demonstrate significant causal effects of gut microbiome on HIV infection. These findings facilitate future studies to develop better strategies for HIV prophylaxis through gut microbiome regulation. Further explorations are also warranted to dissect the mechanism of how gut microbiome affects HIV susceptibility.
... 20 Men are not only considered clients but also partners accountable for the support and agents of change in maternal health care throughout pregnancy, despite their lack of specific understanding of maternal health care. 15,38 Pregnant women have a strong conviction in maternal health care services, which are connected with services that can improve the woman's and fetus' health. The belief system evolved through time by comparing the benefit of the service with and without use on the pregnant woman's and fetus's health outcomes. ...
Purpose
Gender-based perceptions about maternal health care during pregnancy draw attention to the existence of gender inequity in maternal health care. This study aimed to understand the gender-based perception of gender roles and norms, gender relations, social support, and psychosocial variation in maternal health care during pregnancy.
Methods
A qualitative study was conducted in three rural districts of Jimma, Ethiopia. Participants were purposefully chosen from the community groups, including male and female health development armies, religious leaders, health extension workers, midwifery nurses, and primary health care unit directors. The data was gathered through in-depth interviews and focus group discussions. The actual data was collected by men and women qualitative study experts. Atlas ti Ver 9 was used for the analysis. The data was initially coded then changed to a sub-category and at last converted to a category.
Results
Four categories emerged: Gender-based roles and norms, psychosocial variation, social support, and gender relations. The informants described men’s and women’s independent and shared roles improve maternal health care service usage during pregnancy. Once the women became pregnant, men undertook a variety of demanding duties to enhance maternity service consumption. Gender relations and shared decision-making were essential in facilitating maternal healthcare utilization during pregnancy and beyond.
Conclusion
This study revealed that maternal health care should not be limited to women alone. Men’s and women’s prior maternal health experiences, in addition to their knowledge and beliefs, have significantly impacted the utilization of maternal healthcare services during pregnancy. Policymakers and academics should consider men’s essential contribution to maternal health care during pregnancy. However, in order to increase their intention to use maternal health care services, it is necessary to clearly identify the interests of women in which men should be involved.
... Relative risk of per-act HIV transmission due to HSV-2 coinfection (vs HSV-2-uninfected) RR β Lognormal 22 As the study sample was all PLWH, we assumed that it was more likely to also be HSV-2-infected, and assumed that this relative risk among those with GUD episodes should be compared to non-GUD HSV-2 infection Articles HIV transmission or acquisition over 2020-2029, i.e., the cofactors that result in HSV-2 increasing transmission or acquisition risk are set to 1 over this time period. ...
Background:
Evidence suggests HSV-2 infection increases HIV acquisition risk and HIV/HSV-2 coinfection increases transmission risk of both infections. We analysed the potential impact of HSV-2 vaccination in South Africa, a high HIV/HSV-2 prevalence setting.
Methods:
We adapted a dynamic HIV transmission model for South Africa to incorporate HSV-2, including synergistic effects with HIV, to evaluate the impact of: (i) cohort vaccination of 9-year-olds with a prophylactic vaccine that reduces HSV-2 susceptibility; (ii) vaccination of symptomatically HSV-2-infected individuals with a therapeutic vaccine that reduces HSV shedding.
Findings:
An 80% efficacious prophylactic vaccine offering lifetime protection with 80% uptake could reduce HSV-2 and HIV incidence by 84.1% (95% Credibility Interval: 81.2-86.0) and 65.4% (56.5-71.6) after 40 years, respectively. This reduces to 57.4% (53.6-60.7) and 42.1% (34.1-48.1) if efficacy is 50%, 56.1% (53.4-58.3) and 41.5% (34.2-46.9) if uptake is 40%, and 29.4% (26.0-31.9) and 24.4% (19.0-28.7) if protection lasts 10 years. An 80% efficacious therapeutic vaccine offering lifetime protection with 40% coverage among symptomatic individuals could reduce HSV-2 and HIV incidence by 29.6% (21.8-40.9) and 26.4% (18.5-23.2) after 40 years, respectively. This reduces to 18.8% (13.7-26.4) and 16.9% (11.7-25.3) if efficacy is 50%, 9.7% (7.0-14.0) and 8.6% (5.8-13.4) if coverage is 20%, and 5.4% (3.8-8.0) and 5.5% (3.7-8.6) if protection lasts 2 years.
Interpretation:
Prophylactic and therapeutic vaccines offer promising approaches for reducing HSV-2 burden and could have important impact on HIV in South Africa and other high prevalence settings.
Funding:
WHO, NIAID.
... The person-to-person transmission rates (β wm , β mw ) are in the range suggested in [59] and is consistent with the reported transmission probability per coital act reported for HIV [78][79][80]. The model incorporates the assumption made in [55], that human latent period is equivalent to the intrinsic incubation period. ...
Zika Virus (ZIKV) is a flavivirus that is transmitted predominantly by the Aedes species of mosquito, but also through sexual contact, blood transfusions, and congenitally from mother to child. Although approximately 80% of ZIKV infections are asymptomatic and typical symptoms are mild, multiple studies have demonstrated a causal link between ZIKV and severe diseases such as Microcephaly and Guillain Barré Syndrome. Two goals of this study are to improve ZIKV models by considering the spread dynamics of ZIKV as both a vector-borne and sexually transmitted disease, and also to approximate the degree of under-reporting. In order to accomplish these objectives, we propose a compartmental model that allows for the analysis of spread dynamics as both a vector-borne and sexually transmitted disease, and fit it to the ZIKV incidence reported to the National System of Public Health Surveillance in 27 municipalities of Colombia between January 1 2015 and December 31 2017. We demonstrate that our model can represent the infection patterns over this time period with high confidence. In addition, we argue that the degree of under-reporting is also well estimated. Using the model we assess potential viability of public health scenarios for mitigating disease spread and find that targeting the sexual pathway alone has negligible impact on overall spread, but if the proportion of risky sexual behavior increases then it may become important. Targeting mosquitoes remains the best approach of those considered. These results may be useful for public health organizations and governments to construct and implement suitable health policies and reduce the impact of the Zika outbreaks.
... 80 Studies (done in settings outside of Europe) suggest that during ulcerative episodes the risks of HIV acquisition and transmission are even higher. 81,82 A recent epidemiological analysis of the population attributable fraction (PAF) of sexually-acquired incident HIV attributable to HSV-2 among 15-49 years old in the general populations was recently completed for all six WHO regions, 9 including Europe. Here, the classic epidemiological formula for the PAF was used to apply the pooled ARRs of HSV-2 on HIV acquisition from the 2017 systematic review 8 to HSV-2 infection data for Europe for 2016. ...
Background
Herpes simplex virus type 2 (HSV-2) infection is a globally prevalent, life-long, sexually transmitted infection. This study characterized HSV-2 seroprevalence in Europe for various at-risk populations and proportions of HSV-2 detection in genital ulcer disease (GUD) and in genital herpes. Data on neonatal herpes and HSV-2's contribution to HIV transmission were also reviewed.
Methods
Cochrane and PRISMA guidelines were followed to systematically review, synthesize, and report HSV-2 related findings. The search was conducted in PubMed and Embase databases up to February 20, 2022. Any publication reporting data on the outcome measures was included. Meta-analyses and meta-regressions were conducted.
Findings
211 relevant reports were identified, including 12 overall incidence measures, 294 overall (813 stratified by factors such as age and sex) seroprevalence measures, 13 overall (15 stratified by sex) proportions of HSV-2 detection in clinically diagnosed GUD, and 70 overall (183 stratified by factors such as age and sex) proportions of HSV-2 detection in laboratory-confirmed genital herpes. Pooled mean seroprevalence was 12.4% (95% CI: 11.5–13.3%) among general populations, 27.8% (95% CI: 17.5–39.4%) among men who have sex with men, 46.0% (95% CI: 40.1–51.8%) among people living with HIV and people in HIV discordant couples, and 63.2% (95% CI: 55.5–70.6%) among female sex workers. Most measures showed heterogeneity in HSV-2 seroprevalence. The pooled mean seroprevalence among general populations increased with age and was 0.65-fold (95% CI: 0.58–0.74) lower in men than women. Seroprevalence decreased by 1% per calendar year. Pooled mean proportions of HSV-2 detection in GUD and in genital herpes were 22.0% (95% CI: 15.3–29.6%) and 66.0% (95% CI: 62.9–69.1%), respectively. HSV-2 detection in genital herpes cases was 1.21-fold (95% CI: 1.10–1.32) higher in men compared to women and decreased by 1% per calendar year. Incidence of neonatal herpes indicated an increasing trend.
Interpretation
Although seroprevalence is declining, a significant proportion of Europe's population is infected with HSV-2. HSV-2 accounts for approximately one-fifth of GUD cases and two-thirds of genital herpes cases. Findings support the need to invest in HSV-2 vaccine development, and sexual and reproductive health services.
Funding
Qatar National Research Fund [NPRP 9-040-3-008] and pilot funding from the Biomedical Research Program at Weill Cornell Medicine in Qatar supported this study.
... Moreover, future studies should also be performed using primary cells from the rectum, because rectal mucosa is the main route of HIV-1 infection in men who have sex with men [28]. This tissue is very transmissible, with a 10-to 2000-fold relative risk per sexual act compared to vaginal-cervical exposure [29]. Additionally, rectal mucosal tissue constitutes a key anatomical reservoir for established HIV-1 infection [30]. ...
Objectives: Ellagic acid (EA) has a wide range of biological effects. The purpose of this study was to investigate the in vitro effects of EA on HIV-1 replication, viral enzyme activity and cytokine secretion by infected cells. Methods: The anti-HIV-1 activity of EA in solution was determined in vitro using the infection of TZM-bl cells by the nano luciferase-secreting R5-tropic JRCSF strain of HIV-1, which allows for the quantification of viral growth by measuring nano luciferase in the culture supernatants. The effect of EA on the cytokine secretion of TZM-bl cells was determined by a multiplexed bead array after 48 h of HIV-1 exposure. The antiviral effect of EA in the gel formulation (Ellagel), as would be used for vaginal application, was investigated by the inhibition of infection of UC87.CD4.CCR5 cells with R5-tropic pBaLEnv-recombinant HIV-1. Results: EA in solutions of up to 100 µM was not toxic to TZM-bl cells. EA added either 1 h before or 4 h after HIV-1 exposure suppressed the replication of R5-tropic HIV-1 in TZM-bl cells in a dose-dependent manner, with up to 69% inhibition at 50 µM. EA-containing solutions also exhibited a dose-dependent inhibitory effect on HIV-1 replication in U87 cells. When EA was formulated as a gel, Ellagel containing 25 µM and 50 µM EA inhibited HIV-1 replication in U87 cells by 56% and 84%, respectively. In assays of specific HIV-1 enzyme activity, Ellagel inhibited HIV-1 integrase but not protease. EA did not significantly modulate cytokine secretion. Conclusions: We conclude that EA either in solution or in a gel form inhibits HIV infection without adverse effects on target cells. Thus, gel containing EA can be tested as a new microbicide against HIV infection.
Keywords: cytokines; chemokines; ellagic acid; HIV-1; microbicide gel
... HIV discordant partnerships can constitute core risk groups for the transmission of HIV infection [9]. Gray et al. also reported that HIV-negative members of discordant partnerships are at extremely high risk of infection, with the annual incidence of 10 to 100-fold higher than that of their HIV concordant negative counterparts [10]. ...
Background: Discordance has always been a bane in the efforts to stop the spread of HIV within the population as it creates a gap through which re-infection occurs. Knowing the demographics associated with discordance will help in the fight against HIV AIDS transmission. Objectives: The study was conducted to assess the demographic and social factors associated with HIV discordance among HIV-infected couples. Methods: A total of 158 couples and 317 individuals were recruited for the survey using a stratified sampling technique. A detailed closed-ended questionnaire was administered to them to collect their demographic and social information. A blood test was also carried out to confirm their HIV status. Results: The majority 161(50.8%) of respondents had secondary education while the least 29(9.1%) of them had ter-tiary education. Most of the 135(42.6%) knew their HIV status by voluntary testing, and most respondents 255(71%) were Christians while only 92(29%) were Muslims. More women 105(66.04%) were HIV positive, and the HIV discordance prevalence for Kaduna State was 0.2%. Social factors such as education, employment, unprotected sex, extramarital affairs, body marks/tattoo, surgery/operation, tribal marks, and blood transfusion did not affect HIV discordance, p-value ˃ 0.05. Other social factors such as remarriage, use of antiretroviral therapy (ART), premarital sex, male/female circumcision, and polygamy were found to affect HIV discordance, p-value ˂ 0.05. Conclusions: There is a need to draw the attention of HIV-infected couples to these facts to succeed in the global war against HIV AIDS.
... HIV discordant partnerships can constitute core risk groups for the transmission of HIV infection [9]. Gray et al. also reported that HIV-negative members of discordant partnerships are at extremely high risk of infection, with the annual incidence of 10 to 100-fold higher than that of their HIV concordant negative counterparts [10]. ...
Background: Discordance has always been a bane in the efforts to stop the spread of HIV within the population as it creates a gap through which re-infection occurs. Knowing the demographics associated with discordance will help in the fight against HIV AIDS transmission. Objectives: The study was conducted to assess the demographic and social factors associated with HIV discordance among HIV-infected couples. Methods: A total of 158 couples and 317 individuals were recruited for the survey using a stratified sampling technique. A detailed closed-ended questionnaire was administered to them to collect their demographic and social information. A blood test was also carried out to confirm their HIV status. Results: The majority 161(50.8%) of respondents had secondary education while the least 29(9.1%) of them had ter-tiary education. Most of the 135(42.6%) knew their HIV status by voluntary testing, and most respondents 255(71%) were Christians while only 92(29%) were Muslims. More women 105(66.04%) were HIV positive, and the HIV discordance prevalence for Kaduna State was 0.2%. Social factors such as education, employment, unprotected sex, extramarital affairs, body marks/tattoo, surgery/operation, tribal marks, and blood transfusion did not affect HIV discordance, p-value ˃ 0.05. Other social factors such as remarriage, use of antiretroviral therapy (ART), premarital sex, male/female circumcision, and polygamy were found to affect HIV discordance, p-value ˂ 0.05. Conclusions: There is a need to draw the attention of HIV-infected couples to these facts to succeed in the global war against HIV AIDS.
Viruses in human semen may be sexually transmitted via free and cell‐mediated viral infection. The potential effects of semen on the infection and sexual transmission of most viruses in semen remain largely unclear. The present study elucidated the inhibitory effects of human seminal plasma (SP) on Jurkat cell (JC)‐mediated mumps virus (MuV) infection. We demonstrated that MuV efficiently infected JCs and that the JCs infected by MuV (JC‐MuV) mediated MuV infection of HeLa cells. Remarkably, SP was highly cytotoxic to JCs and inhibited JC‐MuV infection of HeLa cells. The cytotoxic factor possessed a molecular weight of less than 3 kDa, whereas that of the viricidal factor was over 100 kDa. The cooperation of cytotoxic and viricidal factors was required for the SP inhibition of JC‐MuV infection, and prostatic fluid (PF) was responsible for both the cytotoxic and viricidal effects of SP. The cytotoxic effects we observed were resistant to the treatment of PF with boiling water, proteinase K, RNase A, and DNase I. Our results provide novel insights into the antiviral properties of SP, which may limit cell‐mediated sexual viral transmission.
Introduction/objectives
The use of non-occupational post-exposure prophylaxis (nPEP) emerges as a strategic intervention to reduce HIV infection risk following sexual encounters in our setting. Notwithstanding, there is a scarcity of contemporary data regarding adherence to this treatment, its effectiveness and tolerance. Our study aims to delve into these factors among individuals who have resorted to nPEP after high-risk sexual encounters.
Methods
We conducted a retrospective observational study of cases administered nPEP for HIV from 1 January 2018 to 31 December 2021 at a tertiary hospital in Madrid. The study included all adults over 18 years who sought care at the emergency department of the Fundación Jiménez Díaz Hospital following a risky sexual encounter and were subsequently recommended HIV nPEP treatment.
Results
878 individuals received nPEP for HIV and underwent initial serological tests. Of these, 621 had comprehensive follow-ups. The prescribed regimen for all was raltegravir (RAL) 1200 mg combined with tenofovir/emtricitabine (TDF/FTC) 245/200 mg daily for 28 days. The study revealed a 1.1% rate (n=10) of previously undetected infection and a 0.16% (n=1) failure rate of nPEP. Regarding regimen tolerability, 5.6% (n=35) experienced symptoms linked to the treatment, yet none necessitated discontinuation of the regimen. On the contrary, six per cent (n=53) reported symptoms consistent with an STI during one of the medical visits; specifically, 4.4% had urethritis, and 1.6% had proctitis.
Conclusion
nPEP with RAL/TDF/FTC demonstrates high efficacy and safety, contingent on proper adherence. There is an observed increase in STI prevalence in this cohort, with nearly half of the participants not engaging in appropriate follow-up after initiating nPEP.
The human immunodeficiency virus (HIV) continues to pose a significant global health challenge, with millions of people affected and new cases emerging each year. While various treatment and prevention methods exist, including antiretroviral therapy and non-vaccine approaches, developing an effective vaccine remains the most crucial and cost-effective solution to combating the HIV epidemic. Despite significant advancements in HIV research, the HIV vaccine field has faced numerous challenges, and only one clinical trial has demonstrated a modest level of efficacy. This review delves into the history of HIV vaccines and the current efforts in HIV prevention, emphasizing pre-clinical vaccine development using the non-human primate model (NHP) of HIV infection. NHP models offer valuable insights into potential preventive strategies for combating HIV, and they play a vital role in informing and guiding the development of novel vaccine candidates before they can proceed to human clinical trials.
A primary concern in epidemics is to minimize the probability of contagion, often resorting to reducing the number of contacted people. However, the success of that strategy depends on the shape of the dose-response curve, which relates the response of the exposed person to the pathogen dose received from surrounding infected people. If the reduction is achieved by spending more time with each contacted person, the pathogen charge received from each infected individual will be larger. The extended time spent close to each person may worsen the expected response if the dose-response curve is convex for small doses. This is the case when the expected response is negligible below a certain dose threshold and rises sharply above it. This study proposes a mathematical model to calculate the expected response and uses it to identify the conditions when it would be advisable to reduce the contact time with each individual even at the cost of increasing the number of contacted people.
Redefining viral load suppression (VLS) using lower cutpoints could impact progress towards the United Nations Programme on HIV/AIDS 95-95-95 targets. We assessed impacts of lowering the VLS cutpoint on achieving the 'third 95' in the Rakai Community Cohort Study. Population VLS would fall from 86% to 84% and 76%, respectively, after lowering VLS cutpoints from <1000 to <200 and <50 copies/ml. The fraction of viremic persons increased by 17% after lowering the VLS cutpoint from <1000 to <200 copies/ml.
Monkeypox (MPX) transmission outside non-endemic countries has been reported since May 2022, rapidly evolving into a multi-country outbreak. A potential role of sexual contact in transmission dynamics, as well as a predominance of anogenitallesions, are remarkable features of current cases. Screening for sexually transmitted infections (STIs) plays an important role in the evaluation of patients with suspected MPX infection. Herein we report the first case of a patient diagnosed with both MPX and acute HIV infection in Latin America. He had no major complications during his clinical course, and antiretroviral therapy was promptly initiated. Diagnosis of acute HIV requires a high level of suspicion and appropriate laboratory investigation. Health practitioners need to consider this diagnosis while evaluating patients with suspected MPX with a recent unprotected sexual contact.
Keywords:
Monkeypox; Acute HIV infection; Sexually transmitted infections
Principles of Medicine in Africa combines classical clinical medicine with a rich understanding of the major environmental and cultural influences on health and disease, providing comprehensive guidance for anyone intending to practise medicine in Africa. Disease is presented in the context of family and culture, and the effects of inequality and problems of limited resources are addressed. The authors have a wealth of experience in front line healthcare and provide practical, evidence-based management guidelines for all the common and less common conditions likely to be encountered. This fourth edition has been thoroughly updated to incorporate the latest research findings and management guidelines. It includes an expanded section on maternal and child health, but careful editing has generated a slimmer volume, whilst retaining all of the essential content. This is the one essential text for medical students and healthcare professionals wanting a complete and up-to-date reference book on medicine in Africa.
Principles of Medicine in Africa combines classical clinical medicine with a rich understanding of the major environmental and cultural influences on health and disease, providing comprehensive guidance for anyone intending to practise medicine in Africa. Disease is presented in the context of family and culture, and the effects of inequality and problems of limited resources are addressed. The authors have a wealth of experience in front line healthcare and provide practical, evidence-based management guidelines for all the common and less common conditions likely to be encountered. This fourth edition has been thoroughly updated to incorporate the latest research findings and management guidelines. It includes an expanded section on maternal and child health, but careful editing has generated a slimmer volume, whilst retaining all of the essential content. This is the one essential text for medical students and healthcare professionals wanting a complete and up-to-date reference book on medicine in Africa.
Principles of Medicine in Africa combines classical clinical medicine with a rich understanding of the major environmental and cultural influences on health and disease, providing comprehensive guidance for anyone intending to practise medicine in Africa. Disease is presented in the context of family and culture, and the effects of inequality and problems of limited resources are addressed. The authors have a wealth of experience in front line healthcare and provide practical, evidence-based management guidelines for all the common and less common conditions likely to be encountered. This fourth edition has been thoroughly updated to incorporate the latest research findings and management guidelines. It includes an expanded section on maternal and child health, but careful editing has generated a slimmer volume, whilst retaining all of the essential content. This is the one essential text for medical students and healthcare professionals wanting a complete and up-to-date reference book on medicine in Africa.
Principles of Medicine in Africa combines classical clinical medicine with a rich understanding of the major environmental and cultural influences on health and disease, providing comprehensive guidance for anyone intending to practise medicine in Africa. Disease is presented in the context of family and culture, and the effects of inequality and problems of limited resources are addressed. The authors have a wealth of experience in front line healthcare and provide practical, evidence-based management guidelines for all the common and less common conditions likely to be encountered. This fourth edition has been thoroughly updated to incorporate the latest research findings and management guidelines. It includes an expanded section on maternal and child health, but careful editing has generated a slimmer volume, whilst retaining all of the essential content. This is the one essential text for medical students and healthcare professionals wanting a complete and up-to-date reference book on medicine in Africa.
Principles of Medicine in Africa combines classical clinical medicine with a rich understanding of the major environmental and cultural influences on health and disease, providing comprehensive guidance for anyone intending to practise medicine in Africa. Disease is presented in the context of family and culture, and the effects of inequality and problems of limited resources are addressed. The authors have a wealth of experience in front line healthcare and provide practical, evidence-based management guidelines for all the common and less common conditions likely to be encountered. This fourth edition has been thoroughly updated to incorporate the latest research findings and management guidelines. It includes an expanded section on maternal and child health, but careful editing has generated a slimmer volume, whilst retaining all of the essential content. This is the one essential text for medical students and healthcare professionals wanting a complete and up-to-date reference book on medicine in Africa.
Principles of Medicine in Africa combines classical clinical medicine with a rich understanding of the major environmental and cultural influences on health and disease, providing comprehensive guidance for anyone intending to practise medicine in Africa. Disease is presented in the context of family and culture, and the effects of inequality and problems of limited resources are addressed. The authors have a wealth of experience in front line healthcare and provide practical, evidence-based management guidelines for all the common and less common conditions likely to be encountered. This fourth edition has been thoroughly updated to incorporate the latest research findings and management guidelines. It includes an expanded section on maternal and child health, but careful editing has generated a slimmer volume, whilst retaining all of the essential content. This is the one essential text for medical students and healthcare professionals wanting a complete and up-to-date reference book on medicine in Africa.
Principles of Medicine in Africa combines classical clinical medicine with a rich understanding of the major environmental and cultural influences on health and disease, providing comprehensive guidance for anyone intending to practise medicine in Africa. Disease is presented in the context of family and culture, and the effects of inequality and problems of limited resources are addressed. The authors have a wealth of experience in front line healthcare and provide practical, evidence-based management guidelines for all the common and less common conditions likely to be encountered. This fourth edition has been thoroughly updated to incorporate the latest research findings and management guidelines. It includes an expanded section on maternal and child health, but careful editing has generated a slimmer volume, whilst retaining all of the essential content. This is the one essential text for medical students and healthcare professionals wanting a complete and up-to-date reference book on medicine in Africa.
Principles of Medicine in Africa combines classical clinical medicine with a rich understanding of the major environmental and cultural influences on health and disease, providing comprehensive guidance for anyone intending to practise medicine in Africa. Disease is presented in the context of family and culture, and the effects of inequality and problems of limited resources are addressed. The authors have a wealth of experience in front line healthcare and provide practical, evidence-based management guidelines for all the common and less common conditions likely to be encountered. This fourth edition has been thoroughly updated to incorporate the latest research findings and management guidelines. It includes an expanded section on maternal and child health, but careful editing has generated a slimmer volume, whilst retaining all of the essential content. This is the one essential text for medical students and healthcare professionals wanting a complete and up-to-date reference book on medicine in Africa.
Principles of Medicine in Africa combines classical clinical medicine with a rich understanding of the major environmental and cultural influences on health and disease, providing comprehensive guidance for anyone intending to practise medicine in Africa. Disease is presented in the context of family and culture, and the effects of inequality and problems of limited resources are addressed. The authors have a wealth of experience in front line healthcare and provide practical, evidence-based management guidelines for all the common and less common conditions likely to be encountered. This fourth edition has been thoroughly updated to incorporate the latest research findings and management guidelines. It includes an expanded section on maternal and child health, but careful editing has generated a slimmer volume, whilst retaining all of the essential content. This is the one essential text for medical students and healthcare professionals wanting a complete and up-to-date reference book on medicine in Africa.
Principles of Medicine in Africa combines classical clinical medicine with a rich understanding of the major environmental and cultural influences on health and disease, providing comprehensive guidance for anyone intending to practise medicine in Africa. Disease is presented in the context of family and culture, and the effects of inequality and problems of limited resources are addressed. The authors have a wealth of experience in front line healthcare and provide practical, evidence-based management guidelines for all the common and less common conditions likely to be encountered. This fourth edition has been thoroughly updated to incorporate the latest research findings and management guidelines. It includes an expanded section on maternal and child health, but careful editing has generated a slimmer volume, whilst retaining all of the essential content. This is the one essential text for medical students and healthcare professionals wanting a complete and up-to-date reference book on medicine in Africa.
Principles of Medicine in Africa combines classical clinical medicine with a rich understanding of the major environmental and cultural influences on health and disease, providing comprehensive guidance for anyone intending to practise medicine in Africa. Disease is presented in the context of family and culture, and the effects of inequality and problems of limited resources are addressed. The authors have a wealth of experience in front line healthcare and provide practical, evidence-based management guidelines for all the common and less common conditions likely to be encountered. This fourth edition has been thoroughly updated to incorporate the latest research findings and management guidelines. It includes an expanded section on maternal and child health, but careful editing has generated a slimmer volume, whilst retaining all of the essential content. This is the one essential text for medical students and healthcare professionals wanting a complete and up-to-date reference book on medicine in Africa.
Principles of Medicine in Africa combines classical clinical medicine with a rich understanding of the major environmental and cultural influences on health and disease, providing comprehensive guidance for anyone intending to practise medicine in Africa. Disease is presented in the context of family and culture, and the effects of inequality and problems of limited resources are addressed. The authors have a wealth of experience in front line healthcare and provide practical, evidence-based management guidelines for all the common and less common conditions likely to be encountered. This fourth edition has been thoroughly updated to incorporate the latest research findings and management guidelines. It includes an expanded section on maternal and child health, but careful editing has generated a slimmer volume, whilst retaining all of the essential content. This is the one essential text for medical students and healthcare professionals wanting a complete and up-to-date reference book on medicine in Africa.
Principles of Medicine in Africa combines classical clinical medicine with a rich understanding of the major environmental and cultural influences on health and disease, providing comprehensive guidance for anyone intending to practise medicine in Africa. Disease is presented in the context of family and culture, and the effects of inequality and problems of limited resources are addressed. The authors have a wealth of experience in front line healthcare and provide practical, evidence-based management guidelines for all the common and less common conditions likely to be encountered. This fourth edition has been thoroughly updated to incorporate the latest research findings and management guidelines. It includes an expanded section on maternal and child health, but careful editing has generated a slimmer volume, whilst retaining all of the essential content. This is the one essential text for medical students and healthcare professionals wanting a complete and up-to-date reference book on medicine in Africa.
Principles of Medicine in Africa combines classical clinical medicine with a rich understanding of the major environmental and cultural influences on health and disease, providing comprehensive guidance for anyone intending to practise medicine in Africa. Disease is presented in the context of family and culture, and the effects of inequality and problems of limited resources are addressed. The authors have a wealth of experience in front line healthcare and provide practical, evidence-based management guidelines for all the common and less common conditions likely to be encountered. This fourth edition has been thoroughly updated to incorporate the latest research findings and management guidelines. It includes an expanded section on maternal and child health, but careful editing has generated a slimmer volume, whilst retaining all of the essential content. This is the one essential text for medical students and healthcare professionals wanting a complete and up-to-date reference book on medicine in Africa.
Principles of Medicine in Africa combines classical clinical medicine with a rich understanding of the major environmental and cultural influences on health and disease, providing comprehensive guidance for anyone intending to practise medicine in Africa. Disease is presented in the context of family and culture, and the effects of inequality and problems of limited resources are addressed. The authors have a wealth of experience in front line healthcare and provide practical, evidence-based management guidelines for all the common and less common conditions likely to be encountered. This fourth edition has been thoroughly updated to incorporate the latest research findings and management guidelines. It includes an expanded section on maternal and child health, but careful editing has generated a slimmer volume, whilst retaining all of the essential content. This is the one essential text for medical students and healthcare professionals wanting a complete and up-to-date reference book on medicine in Africa.
Principles of Medicine in Africa combines classical clinical medicine with a rich understanding of the major environmental and cultural influences on health and disease, providing comprehensive guidance for anyone intending to practise medicine in Africa. Disease is presented in the context of family and culture, and the effects of inequality and problems of limited resources are addressed. The authors have a wealth of experience in front line healthcare and provide practical, evidence-based management guidelines for all the common and less common conditions likely to be encountered. This fourth edition has been thoroughly updated to incorporate the latest research findings and management guidelines. It includes an expanded section on maternal and child health, but careful editing has generated a slimmer volume, whilst retaining all of the essential content. This is the one essential text for medical students and healthcare professionals wanting a complete and up-to-date reference book on medicine in Africa.
Principles of Medicine in Africa combines classical clinical medicine with a rich understanding of the major environmental and cultural influences on health and disease, providing comprehensive guidance for anyone intending to practise medicine in Africa. Disease is presented in the context of family and culture, and the effects of inequality and problems of limited resources are addressed. The authors have a wealth of experience in front line healthcare and provide practical, evidence-based management guidelines for all the common and less common conditions likely to be encountered. This fourth edition has been thoroughly updated to incorporate the latest research findings and management guidelines. It includes an expanded section on maternal and child health, but careful editing has generated a slimmer volume, whilst retaining all of the essential content. This is the one essential text for medical students and healthcare professionals wanting a complete and up-to-date reference book on medicine in Africa.
Principles of Medicine in Africa combines classical clinical medicine with a rich understanding of the major environmental and cultural influences on health and disease, providing comprehensive guidance for anyone intending to practise medicine in Africa. Disease is presented in the context of family and culture, and the effects of inequality and problems of limited resources are addressed. The authors have a wealth of experience in front line healthcare and provide practical, evidence-based management guidelines for all the common and less common conditions likely to be encountered. This fourth edition has been thoroughly updated to incorporate the latest research findings and management guidelines. It includes an expanded section on maternal and child health, but careful editing has generated a slimmer volume, whilst retaining all of the essential content. This is the one essential text for medical students and healthcare professionals wanting a complete and up-to-date reference book on medicine in Africa.
Principles of Medicine in Africa combines classical clinical medicine with a rich understanding of the major environmental and cultural influences on health and disease, providing comprehensive guidance for anyone intending to practise medicine in Africa. Disease is presented in the context of family and culture, and the effects of inequality and problems of limited resources are addressed. The authors have a wealth of experience in front line healthcare and provide practical, evidence-based management guidelines for all the common and less common conditions likely to be encountered. This fourth edition has been thoroughly updated to incorporate the latest research findings and management guidelines. It includes an expanded section on maternal and child health, but careful editing has generated a slimmer volume, whilst retaining all of the essential content. This is the one essential text for medical students and healthcare professionals wanting a complete and up-to-date reference book on medicine in Africa.
Principles of Medicine in Africa combines classical clinical medicine with a rich understanding of the major environmental and cultural influences on health and disease, providing comprehensive guidance for anyone intending to practise medicine in Africa. Disease is presented in the context of family and culture, and the effects of inequality and problems of limited resources are addressed. The authors have a wealth of experience in front line healthcare and provide practical, evidence-based management guidelines for all the common and less common conditions likely to be encountered. This fourth edition has been thoroughly updated to incorporate the latest research findings and management guidelines. It includes an expanded section on maternal and child health, but careful editing has generated a slimmer volume, whilst retaining all of the essential content. This is the one essential text for medical students and healthcare professionals wanting a complete and up-to-date reference book on medicine in Africa.
Principles of Medicine in Africa combines classical clinical medicine with a rich understanding of the major environmental and cultural influences on health and disease, providing comprehensive guidance for anyone intending to practise medicine in Africa. Disease is presented in the context of family and culture, and the effects of inequality and problems of limited resources are addressed. The authors have a wealth of experience in front line healthcare and provide practical, evidence-based management guidelines for all the common and less common conditions likely to be encountered. This fourth edition has been thoroughly updated to incorporate the latest research findings and management guidelines. It includes an expanded section on maternal and child health, but careful editing has generated a slimmer volume, whilst retaining all of the essential content. This is the one essential text for medical students and healthcare professionals wanting a complete and up-to-date reference book on medicine in Africa.
Principles of Medicine in Africa combines classical clinical medicine with a rich understanding of the major environmental and cultural influences on health and disease, providing comprehensive guidance for anyone intending to practise medicine in Africa. Disease is presented in the context of family and culture, and the effects of inequality and problems of limited resources are addressed. The authors have a wealth of experience in front line healthcare and provide practical, evidence-based management guidelines for all the common and less common conditions likely to be encountered. This fourth edition has been thoroughly updated to incorporate the latest research findings and management guidelines. It includes an expanded section on maternal and child health, but careful editing has generated a slimmer volume, whilst retaining all of the essential content. This is the one essential text for medical students and healthcare professionals wanting a complete and up-to-date reference book on medicine in Africa.
Principles of Medicine in Africa combines classical clinical medicine with a rich understanding of the major environmental and cultural influences on health and disease, providing comprehensive guidance for anyone intending to practise medicine in Africa. Disease is presented in the context of family and culture, and the effects of inequality and problems of limited resources are addressed. The authors have a wealth of experience in front line healthcare and provide practical, evidence-based management guidelines for all the common and less common conditions likely to be encountered. This fourth edition has been thoroughly updated to incorporate the latest research findings and management guidelines. It includes an expanded section on maternal and child health, but careful editing has generated a slimmer volume, whilst retaining all of the essential content. This is the one essential text for medical students and healthcare professionals wanting a complete and up-to-date reference book on medicine in Africa.
Principles of Medicine in Africa combines classical clinical medicine with a rich understanding of the major environmental and cultural influences on health and disease, providing comprehensive guidance for anyone intending to practise medicine in Africa. Disease is presented in the context of family and culture, and the effects of inequality and problems of limited resources are addressed. The authors have a wealth of experience in front line healthcare and provide practical, evidence-based management guidelines for all the common and less common conditions likely to be encountered. This fourth edition has been thoroughly updated to incorporate the latest research findings and management guidelines. It includes an expanded section on maternal and child health, but careful editing has generated a slimmer volume, whilst retaining all of the essential content. This is the one essential text for medical students and healthcare professionals wanting a complete and up-to-date reference book on medicine in Africa.
Principles of Medicine in Africa combines classical clinical medicine with a rich understanding of the major environmental and cultural influences on health and disease, providing comprehensive guidance for anyone intending to practise medicine in Africa. Disease is presented in the context of family and culture, and the effects of inequality and problems of limited resources are addressed. The authors have a wealth of experience in front line healthcare and provide practical, evidence-based management guidelines for all the common and less common conditions likely to be encountered. This fourth edition has been thoroughly updated to incorporate the latest research findings and management guidelines. It includes an expanded section on maternal and child health, but careful editing has generated a slimmer volume, whilst retaining all of the essential content. This is the one essential text for medical students and healthcare professionals wanting a complete and up-to-date reference book on medicine in Africa.
Principles of Medicine in Africa combines classical clinical medicine with a rich understanding of the major environmental and cultural influences on health and disease, providing comprehensive guidance for anyone intending to practise medicine in Africa. Disease is presented in the context of family and culture, and the effects of inequality and problems of limited resources are addressed. The authors have a wealth of experience in front line healthcare and provide practical, evidence-based management guidelines for all the common and less common conditions likely to be encountered. This fourth edition has been thoroughly updated to incorporate the latest research findings and management guidelines. It includes an expanded section on maternal and child health, but careful editing has generated a slimmer volume, whilst retaining all of the essential content. This is the one essential text for medical students and healthcare professionals wanting a complete and up-to-date reference book on medicine in Africa.
Principles of Medicine in Africa combines classical clinical medicine with a rich understanding of the major environmental and cultural influences on health and disease, providing comprehensive guidance for anyone intending to practise medicine in Africa. Disease is presented in the context of family and culture, and the effects of inequality and problems of limited resources are addressed. The authors have a wealth of experience in front line healthcare and provide practical, evidence-based management guidelines for all the common and less common conditions likely to be encountered. This fourth edition has been thoroughly updated to incorporate the latest research findings and management guidelines. It includes an expanded section on maternal and child health, but careful editing has generated a slimmer volume, whilst retaining all of the essential content. This is the one essential text for medical students and healthcare professionals wanting a complete and up-to-date reference book on medicine in Africa.
Principles of Medicine in Africa combines classical clinical medicine with a rich understanding of the major environmental and cultural influences on health and disease, providing comprehensive guidance for anyone intending to practise medicine in Africa. Disease is presented in the context of family and culture, and the effects of inequality and problems of limited resources are addressed. The authors have a wealth of experience in front line healthcare and provide practical, evidence-based management guidelines for all the common and less common conditions likely to be encountered. This fourth edition has been thoroughly updated to incorporate the latest research findings and management guidelines. It includes an expanded section on maternal and child health, but careful editing has generated a slimmer volume, whilst retaining all of the essential content. This is the one essential text for medical students and healthcare professionals wanting a complete and up-to-date reference book on medicine in Africa.
Principles of Medicine in Africa combines classical clinical medicine with a rich understanding of the major environmental and cultural influences on health and disease, providing comprehensive guidance for anyone intending to practise medicine in Africa. Disease is presented in the context of family and culture, and the effects of inequality and problems of limited resources are addressed. The authors have a wealth of experience in front line healthcare and provide practical, evidence-based management guidelines for all the common and less common conditions likely to be encountered. This fourth edition has been thoroughly updated to incorporate the latest research findings and management guidelines. It includes an expanded section on maternal and child health, but careful editing has generated a slimmer volume, whilst retaining all of the essential content. This is the one essential text for medical students and healthcare professionals wanting a complete and up-to-date reference book on medicine in Africa.
Principles of Medicine in Africa combines classical clinical medicine with a rich understanding of the major environmental and cultural influences on health and disease, providing comprehensive guidance for anyone intending to practise medicine in Africa. Disease is presented in the context of family and culture, and the effects of inequality and problems of limited resources are addressed. The authors have a wealth of experience in front line healthcare and provide practical, evidence-based management guidelines for all the common and less common conditions likely to be encountered. This fourth edition has been thoroughly updated to incorporate the latest research findings and management guidelines. It includes an expanded section on maternal and child health, but careful editing has generated a slimmer volume, whilst retaining all of the essential content. This is the one essential text for medical students and healthcare professionals wanting a complete and up-to-date reference book on medicine in Africa.
Principles of Medicine in Africa combines classical clinical medicine with a rich understanding of the major environmental and cultural influences on health and disease, providing comprehensive guidance for anyone intending to practise medicine in Africa. Disease is presented in the context of family and culture, and the effects of inequality and problems of limited resources are addressed. The authors have a wealth of experience in front line healthcare and provide practical, evidence-based management guidelines for all the common and less common conditions likely to be encountered. This fourth edition has been thoroughly updated to incorporate the latest research findings and management guidelines. It includes an expanded section on maternal and child health, but careful editing has generated a slimmer volume, whilst retaining all of the essential content. This is the one essential text for medical students and healthcare professionals wanting a complete and up-to-date reference book on medicine in Africa.
Using lookback procedures and other methods, we identified and then prospectively followed human immunodeficiency virus type 1 (HIV-1)-infected transfusion recipients and their sex partners to determine AIDS incidence and risks of heterosexual transmission of HIV-1. At enrollment, 7 of 32 (21.9%) female partners of male recipients were themselves infected with HIV-1, as compared with none of 14 male partners of female recipients (p = 0.08). No additional episodes of transmission were observed. The prevalence of advanced immunodeficiency at enrollment was similar in male and female recipients. Male recipients with advanced immunodeficiency (CD4+ lymphocyte count < or = 0.20 x 10(9)/L or a history of clinical AIDS) at enrollment were more likely to have infected their female partners (odds ratio = 7.9; p = 0.03) than men with neither condition. Similarly, AIDS-free survival, as estimated by the product-limit method, was lower among male transmitters than among male nontransmitters (p = 0.01). Transmission was not associated with frequency of unprotected vaginal intercourse. Our data suggest that HIV-1-infected men who develop immunodeficiency rapidly are more likely to infect their sex partners and that the greater efficiency of male-to-female HIV-1 transmission is not explained by a greater number of sexual contacts or more advanced immunodeficiency in index subjects.
We examined the influence of viral load in relation to other risk factors for the heterosexual transmission of human immunodeficiency virus type 1 (HIV-1). In a community-based study of 15,127 persons in a rural district of Uganda, we identified 415 couples in which one partner was HIV-1-positive and one was initially HIV-1-negative and followed them prospectively for up to 30 months. The incidence of HIV-1 infection per 100 person-years among the initially seronegative partners was examined in relation to behavioral and biologic variables.
The male partner was HIV-1-positive in 228 couples, and the female partner was HIV-1-positive in 187 couples. Ninety of the 415 initially HIV-1-negative partners seroconverted (incidence, 11.8 per 100 person-years). The rate of male-to-female transmission was not significantly different from the rate of female-to-male transmission (12.0 per 100 person-years vs. 11.6 per 100 person-years). The incidence of seroconversion was highest among the partners who were 15 to 19 years of age (15.3 per 100 person-years). The incidence was 16.7 per 100 person-years among 137 uncircumcised male partners, whereas there were no seroconversions among the 50 circumcised male partners (P<0.001). The mean serum HIV-1 RNA level was significantly higher among HIV-1-positive subjects whose partners seroconverted than among those whose partners did not seroconvert (90,254 copies per milliliter vs. 38,029 copies per milliliter, P=0.01). There were no instances of transmission among the 51 subjects with serum HIV-1 RNA levels of less than 1500 copies per milliliter; there was a significant dose-response relation of increased transmission with increasing viral load. In multivariate analyses of log-transformed HIV-1 RNA levels, each log increment in the viral load was associated with a rate ratio of 2.45 for seroconversion (95 percent confidence interval, 1.85 to 3.26).
The viral load is the chief predictor of the risk of heterosexual transmission of HIV-1, and transmission is rare among persons with levels of less than 1500 copies of HIV-1 RNA per milliliter.
As we enter the new millennium the world is still facing the challenge of responding to the AIDS pandemic. A new report from the Joint United Nations Programme on HIV/AIDS presents the latest statistics on prevalence, spread, and impact of the disease. In their Perspective, Schwartländer and his colleagues discuss the newly released statistics and the strategies needed to combat the further spread of HIV/AIDS and to reduce prevalence in the most severely affected countries.
Background: The spread of heterosexual HIV in developing countries is heterogeneous. Factors that explain the wide diversity of HIV prevalences in different countries are undetermined. International aid organizations currently appear to be focusing activities mainly on women rather than on men. Goal: To identify critical determinants contributing to the high rates of heterosexual HIV transmission in developing countries through a review of studies investigating HIV per-act transmission rates, and to discuss how these factors might be prioritized through HIV-prevention interventions. Study Design: Studies investigating the per-act HIV transmission rate were identified through a MEDLINE search and a review of the abstracts of the Annual International AIDS Conferences. Results: When the summary mean per-act HIV transmission rates were calculated, the ratio of female-to-male HIV transmission in developing countries compared with that in the developed world was 341, whereas that for male-to-female transmission was 2.9. Conclusion: Enhanced female-to-male HIV transmission in male core groups is a critical determinant of high-prevalence HIV epidemics among heterosexuals in developing countries. In addition to condom promotion, there is a need for an increased emphasis on HIV-prevention activities in men to decrease their susceptibility in developing countries, particularly in the countries most affected by the epidemic.
To compare the efficiency of male-to-female and female-to-male sexual transmission of human immunodeficiency virus (HIV), we studied 524 female partners of HIV-infected men and 206 male partners of HIV-infected women in 16 Italian clinical centers. All of the partners had had a sexual relationship with the index case lasting for at least 6 months and presented no other risk factor than sexual exposure to the HIV-infected partner. Among the 730 couples, 24% of the female partners were HIV positive, in comparison with 10% of the male partners. Using logistic regression analysis, including gender and controlling for condom use, frequency of intercourse, anal sex, partner's CD4+ cell count and clinical stage, sexually transmitted diseases, genital infections, and contraceptive use, we found that the efficiency of male-to-female transmission was 2.3 (95% confidence interval = 1.1-4.8) times greater than that of female-to-male transmission. Between-gender differences in the contact surfaces and the intensity of exposure to HIV during sexual intercourse are possible reasons for the difference in efficiency of transmission. (Epidemiology 1994;5:570-575)
(C) Lippincott-Raven Publishers.
A prospective study conducted between 1995 and 1998 assessed trends in contraceptive use in rural Rakai District, Uganda. Over a period of 30 months, women's use of modern contraceptives increased significantly from 11 percent to 20 percent. Male condom use increased from 10 percent to 17 percent. The prevalence of pregnancy among sexually active women 15–49 declined significantly from 15 percent to 13 percent. Women practicing family planning for pregnancy prevention were predominantly in the 20–39-year age group, married, better educated, and had higher parity than others, whereas women or men adopting condoms were predominantly young, unmarried, and better educated. Condom use was particularly high among individuals reporting multiple sexual partners or extramarital relationships. Contraceptive use was higher among women who desired fewer children, among those who wished to space or terminate childbearing, and among women with previous experience of unwanted births or abortions. Self-perception of HIV risk increased condom use, but HIV testing and counseling had only modest effects. Contraception for pregnancy prevention and for HIV/STD prophylaxis are complementary.
An immunoblot assay for discrimination of antibodies to herpes simplex virus (HSV) types 1 and 2 was devised using extracts
of recombinant-baculovirus-infected insect cells expressing HSV-l or -2 glycoprotein G (gGI or gG2). The assay was evaluated
by comparing its results with those obtained by using an immunodot assay based on gG immunopurified from HSV-1- and HSV-2-infected
cells. Each of 110 human serum specimens was tested blindly and independently three times. At a serum dilution of 1:20, the
maximum specificities were 96% and 100% and the maximum sensitivities were 100% and 92% for gG1 and gG2, respectively. Reproducibility
was 99% among readers and 95% among individually tested samples of each specimen. Results obtained in two laboratories from
a different set of 15 serum specimens were in complete agreement, indicating the assay is accurate and reproducible. The ease
of antigen production should allow the test to become widely available.
Epidemiologic studies exploring risks for sexually transmitted diseases, including human immunodeficiency virus infection, typically rely on self-report of sexual behaviors. Estimates of the incidence and prevalence of sexual practices are important measures for assessment of behavioral interventions as well as for examining disease transmission. This study examined the degree of agreement within heterosexual couples reporting frequency and type of sexual behaviors, including condom use. Self-reports were obtained from 71 couples attending Baltimore sexually transmitted disease clinics in 1989-1990 regarding the number of days and number of episodes of three specific sexual practices (any type of sexual activity, vaginal sex, and vaginal sex with condom use) over a 30-day period. Paired t test analysis revealed both sexes to be very consistent in their reporting of recent sexual experiences. Multivariate analysis showed that agreement did not vary by socioeconomic status, by whether the partners were married to each other, or by age. These findings suggest that reliable information regarding sexual behaviors may be obtained from men or women.
--To examine rates of heterosexual transmission of human immunodeficiency virus (HIV) and associated risk factors and to determine the relative efficiency of female-to-male and male-to-female transmission.
--Survey of infected individuals and their heterosexual partners recruited since 1985.
--Participants were recruited from various HIV counseling and testing sites throughout California but were generally interviewed and tested in their homes.
--Data from 379 couples at entry to the study are reported: 72 male partners of infected women and 307 female partners of infected men. The infected index case had a well-established source of risk; couples were eliminated if the direction of transmission could not be established. The majority of couples were monogamous since 1978, white, and in their 30s. Most partners did not know their serostatus at entry into the study.
--HIV serostatus in the exposed sexual partner.
--We observed one probable instance (1%) of female-to-male transmission compared with 20% transmission rates in the female partners of infected men. All couples were sampled in the same way. Male index cases were more likely to be symptomatic than female index cases.
--The odds of male-to-female transmission were significantly greater than female-to-male transmission. The one case of female-to-male transmission was unique in that the couple reported numerous unprotected sexual contacts and noted several instances of vaginal and penile bleeding during intercourse.
The Demographic and Health Surveys (DHS) program has included several questions on sexual intercourse in its model questionnaires that have been used in more than 25 surveys in Latin America, Africa, and Asia over the last five years. This article assesses the quality of the data on sexual intercourse for 12 DHS surveys and shows how these data may be useful for understanding contraceptive use dynamics and for organizing the management of family planning programs. The data show that there is considerable variation among countries in exposure to pregnancy prior to first marriage. Within marriage, the level of coital frequency varies with duration of marriage, fertility intentions, and type of contraceptive method used. Finally, in all countries there is some overlap between contraceptive use and sexual abstinence. This information can be useful in family planning programs for targeting particular populations, for assisting women to choose a method, and for assessing the effect of contraceptive use on fertility.
Partner studies produce data on the infection status of partners of individuals known or assumed to be infected with the human immunodeficiency virus (HIV) after a known or estimated number of contacts. Previous studies have assumed a constant probability of transmission (infectivity) of the virus at each contact. Recently, interest has focused on the possibility of heterogeneity of infectivity across partnerships. This paper develops parametric and nonparametric procedures based on partner data in order to examine the risk of infection after a given number of contacts. Graphical methods and inference techniques are presented that allow the investigator to evaluate the constant infectivity model and consider the impact of heterogeneity of infectivity, error in measurement of the number of contacts, and regression effects of other covariates. The majority of the methods can be computationally implemented easily with use of software to fit generalized linear models. The concepts and techniques are closely related to ideas from discrete survival analysis. A data set on heterosexual transmission is used to illustrate the methods.
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.
To describe the role of men and women as sources of HIV transmission and to estimate HIV incidence among discordant couples resident in diverse rural communities in Uganda.
Rakai, a rural district in Uganda, East Africa.
A population-based cohort study, which has been conducted as annual serological and behavioral surveys since 1989. Community clusters were stratified into trading centers on main roads, intermediate trading villages on secondary roads and agricultural villages off roads. In the 1990 survey round, serological data were available for 79 discordant and 411 concordant HIV-negative couples aged 13-49 years. The present analysis examines sex-specific seropositivity associated with place of residence and the incidence of seroconversion among discordant couples between 1990 and 1991.
Seventy-nine discordant couples were followed; the HIV-positive partner was male in 44 couples (57%) and female in 35 couples (43%). There was marked variation in the sex of the seropositive partner by place of residence: women were the HIV-positive partner in 57% of couples from trading centers, 52% from intermediate villages, and 20% from agricultural communities (P < 0.008). Condom use was higher in discordant couples in which the man was the uninfected partner (17.1%) rather than the woman (9.5%). HIV-positive women, but not HIV-positive men, reported significantly more sexual partners and more genital ulcers than seronegative individuals of the same sex. Seroincidence rates among men and women in discordant relationship were 8.7 and 9.2 per 100 person-years (PY), respectively, which was much higher than in concordant seronegative couples (men, 0.82; women, 0.87 per 100 PY).
In this Ugandan population, men are the predominant source of new infections in rural villages. Risk factors and preventive behaviors vary with the sex of the infected partner, and seroconversion rates are similar in both sexes.
A heterosexual partners survey in rural Senegal, Africa, was carried out in 1992 to evaluate the reliability of self-reported answers about sexual practices. The authors followed 62 married couples weekly during a 5-week period to assess the level of agreement 1) between answers made by members of the same couple but collected separately, 2) between retrospective reporting of sexual activity during the last 4 weeks versus weekly reporting of sexual activity during 4 weeks, and 3) between answers to a set of identical retrospective questions asked 5 weeks apart. Reports over recent and short periods of time such as 7 days are reliable: The dates of sexual acts with spouse reported during the weekly interviews were concordant between members of a couple at 0-day or 1-day intervals in 72% of cases. The concordance of weeks reported with or without intercourse was also high. Reports over longer periods of time are less reliable: The comparison of retrospective reports versus weekly reports regarding mean number of sexual acts during the last 4 weeks shows a clear overreporting that was higher among men (4.5 vs. 2.7 sexual acts) than among women (3.7 vs. 2.7).
To compare the efficiency of male-to-female and female-to-male sexual transmission of human immunodeficiency virus (HIV), we studied 524 female partners of HIV-infected men and 206 male partners of HIV-infected women in 16 Italian clinical centers. All of the partners had had a sexual relationship with the index case lasting for at least 6 months and presented no other risk factor than sexual exposure to the HIV-infected partner. Among the 730 couples, 24% of the female partners were HIV positive, in comparison with 10% of the male partners. Using logistic regression analysis, including gender and controlling for condom use, frequency of intercourse, anal sex, partner's CD4+ cell count and clinical stage, sexually transmitted diseases, genital infections, and contraceptive use, we found that the efficiency of male-to-female transmission was 2.3 (95% confidence interval = 1.1-4.8) times greater than that of female-to-male transmission. Between-gender differences in the contact surfaces and the intensity of exposure to HIV during sexual intercourse are possible reasons for the difference in efficiency of transmission.
The epidemic of human immunodeficiency virus type 1 (HIV-1) infection in Thailand has allowed an estimate to be made of the probability of female-to-male HIV-1 transmission per sexual contact. In a study of 1115 21-year-old male military conscripts, of whom 77 (6.9%) were HIV-1 seropositive, sex with female prostitutes was identified as the principal mode of HIV-1 transmission. With a mathematical model including data on conscript's age at first sexual contact, frequency of sex with female prostitutes, and province of origin; as well as province-specific HIV-1 seroprevalence of prostitutes, we estimated the probability of HIV-1 transmission per sexual contact to be 0.031 (95% confidence limits [CL] 0.025-0.040). Allowing for random error in the self-reported frequency of contacts, the estimate was 0.056 (95% CL 0.041-0.075). The transmission probability was significantly greater among men with a history of sexually-transmitted diseases. These estimates are substantially higher than analogous estimates made in North America. This high per-act probability of heterosexual transmission helps to explain the rapid spread of HIV-1 in the emerging epidemic in Thailand and perhaps in other countries where HIV-1 transmission is predominantly heterosexual.
Worldwide, the predominant mode of human immunodeficiency virus (HIV) transmission is heterosexual intercourse, but the risk of heterosexual transmission and the effectiveness of measures to prevent it are not well defined.
We conducted a prospective study of HIV-negative subjects whose only risk of HIV infection was a stable heterosexual relationship with an HIV-infected partner. Every six months the subjects were interviewed, tested for HIV, and counseled about safe sexual practices.
A total of 304 HIV-negative subjects (196 women and 108 men) were followed for an average of 20 months. During the study, 130 couples (42.8 percent) ended their sexual relationships, most often because of the HIV-infected partner's illness or death. Of the 256 couples who continued to have sexual relations for more than three months after enrollment in the study, only 124 (48.4 percent) used condoms consistently for vaginal and anal intercourse. Among these couples, none of the seronegative partners became infected with HIV, despite a total of about 15,000 episodes of intercourse. Among the 121 couples who used condoms inconsistently, the rate of seroconversion was 4.8 per 100 person-years (95 percent confidence interval, 2.5 to 8.4). Eleven couples refused to answer questions about condom use. The risk of transmission increased with advanced stages of HIV infection in the index partners (P < 0.02) and with genital infection in the HIV-negative partners (P < 0.04). Withdrawal to avoid ejaculation in the vagina had a protective effect in uninfected women (P < 0.02).
Consistent use of condoms for heterosexual intercourse is highly effective in preventing the transmission of HIV. Among couples not using condoms regularly, the risk of HIV transmission varies widely.
KAP surveys have been proposed as a means to gather quantitative information on AIDS-related sexual behaviors, but the validity of survey results has not been tested. The validity of data gathered during a KAP survey in a rural district in Northern Uganda (N = 1486) was examined analyzing expected behavioral patterns, agreement of partner reports, and concordance of number of sexual contacts across gender. Patterns of sexual behavior and age trends are as expected. More men (50%) than women (18.5%) reported premarital sex. The likelihood of sexual intercourse before marriage increases with age at first marriage and with education. Women marry 5 years earlier than men, and the number of marriages increases with age. Peak incidence of casual sex occurs before age 25. The male/female ratio of casual sex is 4, as compared to about 3 in other African surveys. Single men are 2.5 times more likely to engage in casual sex than married males. Agreement of partner reports was examined for 392 couples selected by chance. 86% of the couples agreed on being polygamous or monogamous. On average men reported 1.3 (SD = 0.7) wives as compared to women reporting 1.5 (SD = 0.89) wives (P < 0.001). 16.8% of women declared more, and 2.8% less cowives than their husband (r = 0.65). Self-reports on frequency of sexual intercourse in the past month were examined for 256 monogamous couples. Mean frequencies differ (5.24 +/- 5.1 for men, 4.43 +/- 4.7 for women, P < 0.001). 42.8% of couples are in agreement within +/- 1 unit (r = 0.44). The total number of extra-marital and marital sex acts, as well as the total number of partners reported by each gender are similar. There is, however, a striking gender difference in reporting of casual partners in the past year. Data were found to be accurate at the aggregate level. However, accuracy of reporting at the individual level was found to be low. The gender difference in reporting of casual partners may be due to female underreporting, to not having captured prostitutes or to a different perception of the meaning of casual partnership. All KAP surveys should include a validity analysis, so as to provide a sense of the accuracy of the surveys and allow for comparison of the quality of different KAP surveys. There is an urgent need for a standardized approach to validating the findings from AIDS-related KAP surveys. Some of the indirect methods described here could be relevant for further use.
Most of the people now living with HIV acquired the infection through heterosexual intercourse. HIV transmission has been facilitated by (a) concomitant sexually transmitted diseases (STDs), (b) the presence of social conditions that create core groups who have frequent and numerous partners, (c) sexual practices associated with bleeding (i.e., trauma, sex during menses) as well as noncircumcision, (d) cervical ectopy, and (e) anal sex. HIV may be found both cell-free and as intracellular virus in genital tract secretion, and may be sexually transmitted through either mechanism. HIV titers in genital tract secretions vary by several logs between people and within individuals over time, being greatest just after seroconversion and with advanced immunosuppression, concomitant genital tract inflammation (including STDs), and decreasing (but not to zero) with antiretroviral therapy. The per-contact transmission efficiency rate is highly variable, ranging from > 3% to < 1 per thousand contacts, with male-to-female HIV transmission generally being more efficient than vice versa. Control of the heterosexual HIV epidemic will necessitate a multidisciplinary approach, utilizing direct biological approaches (e.g., culturally specific and behavioral interventions, as well as more fundamental community changes that decrease societal norms that augment unsafe practices.
This article focuses on the epidemiology and biology of the host-related factors that affect the sexual transmission of HIV. It discusses host susceptibility and infectiousness environment biologic agent and preventing sexually transmitted HIV infection.
To describe the design and first-round survey results of a trial of intensive sexually transmitted disease (STD) control to reduce HIV-1 incidence.
Randomized, controlled, community-based trial in Rakai District, Uganda.
In this ongoing study, 56 communities were grouped into 10 clusters designed to encompass social/sexual networks; clusters within blocks were randomly assigned to the intervention or control arm. Every 10 months, all consenting resident adults aged 15-59 years are visited in the home for interview and sample collection (serological sample, urine, and, in the case of women, self-administered vaginal swabs). Sera are tested for HIV-1, syphilis, gonorrhea, chlamydia, trichomonas and bacterial vaginosis. Following interview, all consenting adults are offered directly observed, single oral dose treatment (STD treatment in the intervention arm, anthelminthic and iron-folate in the control arm). Treatment is administered irrespective of symptoms or laboratory testing (mass treatment strategy). Both arms receive identical health education, condom and serological counseling services.
In the first home visit round, the study enrolled 5834 intervention and 5784 control arm subjects. Compliance with interview, sample collection and treatment was high in both arms (over 90%). Study arm populations were comparable with respect to sociodemographic and behavioral characteristics, and baseline HIV and STD rates. The latter were high: 16.9% of all subjects were HIV-positive, 10.0% had syphilis, and 23.8% of women had trichomonas and 50.9% had bacterial vaginosis.
Testing the effects of STD control on AIDS prevention is feasible in this Ugandan setting.
The study tested the hypothesis that community-level control of sexually transmitted disease (STD) would result in lower incidence of HIV-1 infection in comparison with control communities.
This randomised, controlled, single-masked, community-based trial of intensive STD control, via home-based mass antibiotic treatment, took place in Rakai District, Uganda. Ten community clusters were randomly assigned to intervention or control groups. All consenting residents aged 15-59 years were enrolled; visited in the home every 10 months; interviewed; asked to provide biological samples for assessment of HIV-1 infection and STDs; and were provided with mass treatment (azithromycin, ciprofloxacin, metronidazole in the intervention group, vitamins/anthelmintic drug in the control). Intention-to-treat analyses used multivariate, paired, cluster-adjusted rate ratios.
The baseline prevalence of HIV-1 infection was 15.9%. 6602 HIV-1-negative individuals were enrolled in the intervention group and 6124 in the control group. 75.0% of intervention-group and 72.6% of control-group participants provided at least one follow-up sample for HIV-1 testing. At enrolment, the two treatment groups were similar in STD prevalence rates. At 20-month follow-up, the prevalences of syphilis (352/6238 [5.6%]) vs 359/5284 [6.8%]; rate ratio 0.80 [95% CI 0.71-0.89]) and trichomoniasis (182/1968 [9.3%] vs 261/1815 [14.4%]; rate ratio 0.59 [0.38-0.91]) were significantly lower in the intervention group than in the control group. The incidence of HIV-1 infection was 1.5 per 100 person-years in both groups (rate ratio 0.97 [0.81-1.16]). In pregnant women, the follow-up prevalences of trichomoniasis, bacterial vaginosis, gonorrhoea, and chlamydia infection were significantly lower in the intervention group than in the control group. No effect of the intervention on incidence of HIV-1 infection was observed in pregnant women or in stratified analyses.
We observed no effect of the STD intervention on the incidence of HIV-1 infection. In the Rakai population, a substantial proportion of HIV-1 acquisition appears to occur independently of treatable STD cofactors.
When human immunodeficiency virus type 1 (HIV-1) was identified as the cause of AIDS more than 15 years ago, it seemed possible that an end to the epidemic would follow. However, the control of communicable diseases requires far more than the identification of causative pathogens. It also requires an understanding of the ways in which a pathogen is spread; an understanding of the biologic, behavioral, and social requirements for transmission; the development of both biologic and behavioral approaches to prevention; the mobilization of social and political forces; and money. Perhaps no disease has highlighted the importance of these requirements more . . .
The spread of heterosexual HIV in developing countries is heterogeneous. Factors that explain the wide diversity of HIV prevalences in different countries are undetermined. International aid organizations currently appear to be focusing activities mainly on women rather than on men.
To identify critical determinants contributing to the high rates of heterosexual HIV transmission in developing countries through a review of studies investigating HIV per-act transmission rates, and to discuss how these factors might be prioritized through HIV-prevention interventions.
Studies investigating the per-act HIV transmission rate were identified through a MEDLINE search and a review of the abstracts of the Annual International AIDS Conferences.
When the summary mean per-act HIV transmission rates were calculated, the ratio of female-to-male HIV transmission in developing countries compared with that in the developed world was 341, whereas that for male-to-female transmission was 2.9.
Enhanced female-to-male HIV transmission in male core groups is a critical determinant of high-prevalence HIV epidemics among heterosexuals in developing countries. In addition to condom promotion, there is a need for an increased emphasis on HIV-prevention activities in men to decrease their susceptibility in developing countries, particularly in the countries most affected by the epidemic.
and the Rakai Project Team* *Members listed at end of paper Departments of Population and Family Health Sciences
- Ronald
- Gray
- Maria
- Ron Wawer
- Brookmeyer
- Nelson
- David Sewankambo
- Fred Serwadda
- Tom Wabwire-Mangen
- Xianbin Lutalo
- Thomas Li
- Vancott
- Thomas
- Quinnr
- X-B Md Gray
- Li
Ronald H Gray, Maria J Wawer, Ron Brookmeyer, Nelson K Sewankambo, David Serwadda, Fred Wabwire-Mangen, Tom Lutalo, Xianbin Li, Thomas vanCott, Thomas C Quinn, and the Rakai Project Team* *Members listed at end of paper Departments of Population and Family Health Sciences (R H Gray MD, X-B Li PhD), Biostatistics (R Brookmeyer PhD), and Medicine (T C Quinn MD), School of Hygiene and Public Health, Johns Hopkins University, Baltimore, MD, USA; Heilbrun Center for Population and Family Health, Columbia University, Joseph L Mailman School of Public Health, New York, NY, USA (M J Wawer MD);
HIV-1 V3 serotypes among civilian applications for US military service
- Renzullo P W Sateran
- F Mccutchan
18 Renzullo P, Sateran W, McCutchan F, et al. HIV-1 V3 serotypes among civilian applications for US military service, 1989–1998. 13th International AIDS Conference, Durban, South Africa, July, 2000 (abstr).
Correspondence to: Dr Ronald H Gray
- Md Bethesda
- Quinn
and National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD (T C Quinn) Correspondence to: Dr Ronald H Gray, Suite 4030, Johns Hopkins University, School of Hygiene and Public Health, 615 N Wolfe Street, Baltimore, MD 21205, USA (e-mail: rgray@jhsph.edu)
for the Rakai Project Study Group. Viral load and heterosexual transmission of human immunodefficiency virus type 1
- Quinn Tc Wawer Mj
- N Sewankambo
Quinn TC, Wawer MJ, Sewankambo N, et al, for the Rakai Project Study Group. Viral load and heterosexual transmission of human immunodefficiency virus type 1. N Engl J Med 2000; 342: 921–29.
Female-to-male transmission of human immunodeficiency virus
- Padian
Probability of male-to-female HIV transmission among married couples in Chiang Mai, Thailand
- Duerr
Full genome sequencing of HIV-1 reveals new complexity in the pandemic
- McCutchan
HIV-1 V3 serotypes among civilian applications for US military service, 1989–1998
- Renzullo