AIDS in Africa: an epidemiologic paradigm

Modeling the potential impact of pre-exposure prophylaxis for HIV among men who have sex with men in Cameroon

Background

Men who have sex with men (MSM) are consistently burdened by HIV at higher levels than other adults. While HIV prevention programs for MSM are growing in coverage and quality, HIV incidence remains high. In response, pre-exposure prophylaxis (PrEP) was introduced in 2019 to support HIV risk reduction among MSM in Cameroon. Understanding how PrEP initiation programs will change the HIV prevalence among MSM in Cameroon is important to developing effective programs.

Methods

This study uses a mathematical model to simulate population-level HIV transmission among MSM in the cities of Yaoundé and Douala, Cameroon. PrEP is incorporated into the model at rates that equal 25%, 50%, or 75% coverage after twenty years to assess the potential effects on HIV prevalence among MSM, requiring annual initiation rates of 2.5%, 6.8%, and 17.2% for Yaoundé and 2.2%, 5.6%, and 13.4% for Douala, respectively. The data utilized for this model are from a cross sectional study which recruited MSM through respondent-driven sampling of MSM in two major cities in Cameroon: Yaoundé and Douala.

Results

The model estimated an HIV prevalence of 43.2% among MSM, annual HIV diagnoses of 300 per 10,000 MSM and antiretroviral therapy (ART) coverage of 53.9% in Yaoundé. In Douala, estimated prevalence is 26.5% among MSM, 167 per 10,000 MSM annual diagnoses and ART coverage of 72.0%. Standalone PrEP interventions aimed at 50% coverage at the end of a 20-year program would reduce the prevalence from 43.2% to 35.4% in Yaoundé and from 26.5 to 20.1% in Douala. Combining PrEP with a 10% increase in HIV testing would decrease the number of MSM living with HIV and unaware of their status from 9.8 to 6.0% in Yaoundé and from 8.7 to 4.6% in Douala.

Conclusions

PrEP would be beneficial in reducing prevalence even at varying initiation and coverage levels. Combination of PrEP and increased HIV testing further decreased the number of undiagnosed MSM. This study supports the utility of implementing PrEP as part of comprehensive HIV prevention programming among MSM in Cameroon.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-022-07738-z.

HIV / AIDS as a model for emerging infectious disease: origin, dating and circumstances of an emblematic epidemiological success

In June 1981, the Centers for Disease Control (CDC) "Morbidity and Mortality Weekly Report" described the first cases of what was to be known as the Acquired Immunodeficiency Syndrome (AIDS). Two years later, the agent responsible for the disease, the human immunodeficiency virus (HIV), was identified. Since then, according to the World Health Organization an estimated 40 million people have died from the disease. Where does this virus come from, and why such an emergence in the late 20^th century? These are the questions that it is now possible to answer in large part thanks to the numerous studies published over a little more than three decades. As with other emerging infectious diseases, initial cross-species transmission from an animal reservoir and subsequent favorable sociological factors associated with the evolution of human societies have led to the spread of a dramatic disease, for which no vaccine is presently available.

From general to specific: moving past the general population in the HIV response across sub-Saharan Africa

INTRODUCTION

As the HIV field evolves to better serve populations which are diverse in risk and access to services, it is crucial to understand and adapt the conceptual tools used to make sense of the HIV pandemic. In this commentary, we discuss the concept of general population. Using a synthetic and historical review, we reflect on the genesis and usage of the general population in HIV research and programme literature, pointing to its moral connotations and its impact on epidemiologic reasoning.

DISCUSSION

From the early days of the HIV pandemic, the category of general population has carried implicit normative meanings. General population represented those people considered to be undeserving of HIV acquisition, and therefore deserving of a response. Framing the HIV epidemic in sub-Saharan Africa as a generalized epidemic primarily affecting the general population has contributed to the exclusion of men who have sex with men from epidemic responses. The usage of this category has also masked heterogeneity among those it includes; the increasing focus on the use of interventions such as circumcision and HIV treatment as general population HIV prevention approaches has been marked by a lack of attention to heterogeneity among beneficiaries.

CONCLUSIONS

We recommend that the term general population be retired from the field's lexicon. HIV programmes should strengthen their capacity to describe the heterogeneity of those they serve and plan their interventions accordingly. To increase the efficiency and impact of the HIV response, it is urgent to stratify the category of general population by risk. Sexual networks are a promising basis for this stratification.

Use of gender distribution in routine surveillance data to detect potential transmission of gastrointestinal infections among men who have sex with men in England

Detecting gastrointestinal (GI) infection transmission among men who have sex with men (MSM) in England is complicated by a lack of routine sexual behavioural data. We investigated whether gender distributions might generate signals for increased transmission of GI pathogens among MSM. We examined the percentage male of laboratory-confirmed patient-episodes for patients with no known travel history for 10 GI infections of public health interest in England between 2003 and 2013, stratified by age and region. An adult male excess was observed for Shigella spp. (annual maximum 71% male); most pronounced for those aged 25-49 years and living in London, Brighton and Manchester. An adult male excess was observed every year for Entamoeba histolytica (range 59.8-76.1% male), Giardia (53.1-57.6%) and Campylobacter (52.1-53.5%) and for a minority of years for hepatitis A (max. 69.8%) and typhoidal salmonella (max. 65.7%). This approach generated a signal for excess male episodes for six GI pathogens, including a characterised outbreak of Shigella among MSM. Stratified analyses by geography and age group were consistent with MSM transmission for Shigella. Optimisation and routine application of this technique by public health authorities elsewhere might help identify potential GI infection outbreaks due to sexual transmission among MSM, for further investigation.

AIDS in the African Press

Newspapers have the potential to take a leading role in AIDS education in Africa. With their relatively small circulations, they mainly reach educated urban citizens, a population particularly hard hit by the epidemic. This study reports findings of a content analysis of AIDS coverage of government owned newspapers in Senegal, Togo, Nigeria, Uganda and Kenya. Although most papers have printed educational articles, they have undertaken only a very minor role in any national effort. Coverage has tended to reflect government reaction, usually moving through stages of denial, scapegoating and blame before responding constructively to the epidemic. African countries surveyed are still largely engaged in epidemiological response to the epidemic; widespread education has not yet occurred. Newspapers have not yet fulfilled their potential as educational media.

From Third World to First World: new roles and challenges for development communication

The terms development and development communication have been, almost always, synonymous with the needs and problems of developing nations or the Third World. In the First World, these terms have not been readily used or easily recognized. The reasoning behind this has been that an industrially advanced country does not have significant problems dealing with development. This may not always be true. An advanced country has pockets of underdevelopment. Second, an industrially advanced country may have other unique problems that have arisen after development. These problems of "overdevelopment" that have occurred during the post-industrial stage may prove to be as dysfunctional as the problems of underdevelopment.

This study will review the problems of underdevelopment and overdevelopment in the First World using mostly the United States of America as a case study. The role and challenges for communication will be discussed with specific reference to the above mentioned problems using the knowledge gained from research in the Third World.

Nosocomial Transmission of HIV in Africa: What Tribute Is Paid to Contaminated Blood Transfusions and Medical Injections?

We reviewed the published data on the possible impact of medical injections and blood transfusions on the spread of human immunodeficiency virus (HIV) in Africa. We also compared these results to our experience in Rwanda, central Africa. The importance of medical injections in the epidemic of HIV infection seems to differ from one area to another. The excess of injections experienced by HIV seropositive subjects in Zaire could be secondary to the parenteral treatment of early HIV-related illness or to the treatment of sexually transmitted diseases, rather than being the cause of HIV infection, as suggested by Rwandese studies. In contrast, blood transfusions have been shown to represent an important source of nosocomial HIV infection in many African countries. Effective and relatively inexpensive measures to diminish the iatrogenic spread of HIV infection in developing countries are summarized.

Epidemiology of human immunodeficiency virus-1 and hepatitis B virus co-infection and risk factors for acquiring these infections in the Fako division of Southwest Cameroon

Background

Past studies have demonstrated that a large population of Cameroonians are afflicted with human immunodeficiency virus (HIV) and/or hepatitis B virus (HBV) demonstrating a need for better prevention programs. We aim to describe the prevalence of HIV, HBV and HIV/HBV co-infection; examine the association between HIV and HBV; and determine risk correlates associated with HIV and HBV transmission in Southwest Cameroon.

Methods

A cross-sectional, community-based surveillance study was conducted among adults in five hospitals , one in each of the five health districts of  the Fako division of the Southwest region of Cameroon. Participants underwent pre- and post-test counselling, a 30-question survey and blood draw for HIV and HBV serologic testing. To construct a final model, chi-squared tests and logistic regression were used to investigate associations.

Results

Among 761 participants, 40.32 % were male, mean age was 35.21 ± 12.42 years, and the prevalence of HIV, HBV and HIV/HBV co-infection was 10.69 % , 9.86 % , and 1.16 % , respectively. There was no association between HIV and HBV infection. However, there was a statistically significant crude associated (p-value < 0.05) between HIV and three high-risk sexual behaviour variables: condom use, number of lifetime sexual partners, and age at first sexual intercourse. After adjustment, HIV status continued to be associated with number of lifetime sexual partners (adjusted odds ratio (AOR) = 2.26; 95 % confidence interval (CI) =1.22–4.17) and age at first sexual intercourse (AOR = 2.63; 95 % CI =1.44–4.81). In contrast, none of the high-risk sexual behaviours was associated with HBV.

Conclusions

The prevalence of HIV and HBV was relatively high in the Southwest region of Cameroon, emphasizing the importance of intervention and treatment programs in this country. Additionally, the results from this study suggest that unlike HIV, HBV is not associated with sexual risk factors and may provide evidence that HBV is acquired through routes other than sexual transmission, warranting further investigation in this region.

AIDS in Africa: distinguishing fact and fiction

The data widely purporting to show the existence and heterosexual transmission in Africa of a new syndrome caused by a retrovirus which induces immune deficiency are critically evaluated. It is concluded that both acquired immune deficiency (AID) and the symptoms and diseases which constitute the clinical syndrome (S) are of long standing in Africa, affect both sexes equally and are caused directly and indirectly by factors other than human immunodeficiency virus (HIV). Seropositivity to HIV in Africans usually represents no more than cross-reactivity caused by an abundance of antibodies induced by the numerous infectious and parasitic diseases which are endemic in Africa. The apparently high prevalence of 'AIDS' and 'HIV' seropositives is therefore not surprising and is not proof of heterosexual transmission of either HIV or AIDS.

Engagement with HIV prevention treatment and care among female sex workers in Zimbabwe: a respondent driven sampling survey

Objective(S)

To determine the HIV prevalence and extent of engagement with HIV prevention and care among a representative sample of Zimbabwean sex workers working in Victoria Falls, Hwange and Mutare.

Design

Respondent driven sampling (RDS) surveys conducted at each site.

Methods

Sex workers were recruited using respondent driven sampling with each respondent limited to recruiting 2 peers. Participants completed an interviewer-administered questionnaire and provided a finger prick blood sample for HIV antibody testing. Statistical analysis took account of sampling method.

Results

870 women were recruited from the three sites. HIV prevalence was between 50 and 70%. Around half of those confirmed HIV positive were aware of their HIV status and of those 50-70% reported being enrolled in HIV care programmes. Overall only 25-35% of those with laboratory-confirmed HIV were accessing antiretroviral therapy. Among those reporting they were HIV negative, 21-28% reported having an HIV test in the last 6 months. Of those tested HIV negative, most (65-82%) were unaware of their status. Around two-thirds of sex workers reported consistent condom use with their clients. As in other settings, sex workers reported high rates of gender based violence and police harassment.

Conclusions

This survey suggests that prevalence of HIV is high among sex workers in Zimbabwe and that their engagement with prevention, treatment and care is sub-optimal. Intensifying prevention and care interventions for sex workers has the potential to markedly reduce HIV and social risks for sex workers, their clients and the general population in Zimbabwe and elsewhere in the region.

The urban poor: an appropriate population for breastfeeding promotion programs

Breastfeeding has won universal endorsement as a major contributor to child survival. The proliferation of breastfeeding promotion programs demonstrates the importance health professionals and funding agencies place on improving the incidence and duration of breastfeeding. An effective, cost-efficient breastfeeding promotion program should be directed at those who will receive the greatest health benefit from such an intervention, i.e., the group who 1) would experience the greatest threat to health by decreasing its breastfeeding practice, and 2) is at greatest risk of changing its breastfeeding habits. Since it is the urban poor primarily who satisfy both of these criteria breastfeeding promotion strategies should focus on them.

The impact of the AIDS pandemic on health services in Africa: evidence from demographic and health surveys

We document the impact of the AIDS crisis on non-AIDS-related health services in 14 sub-Saharan African countries. Using multiple waves of Demographic and Health Surveys (DHS) for each country, we examine antenatal care, birth deliveries, and rates of immunization for children born between 1988 and 2005. We find deterioration in nearly all these dimensions of health care over this period. The most recent DHS survey for each country collected data on HIV prevalence, which allows us to examine the association between HIV burden and health care. We find that erosion of health services is the largest in regions that have developed the highest rates of HIV. Regions of countries that have light AIDS burdens have witnessed small or no declines in health care, using the measures noted above, while those regions shouldering the heaviest burdens have seen the largest erosion in non-HIV-related health services for pregnant women and children. Using semiparametric techniques, we can date the beginning of the divergence in the use of antenatal care and in children's immunizations between high- and low-HIV regions to the mid-1990s.

Tuberculosis as part of the natural history of HIV infection in developing countries

An enhanced, refocused research agenda is critical to reducing the burden of tuberculosis (TB) in the human immunodeficiency virus (HIV) epidemic in developing countries. TB threatens HIV-infected patients before and after initiation of antiretroviral therapy, is difficult to diagnose, is rapidly fatal when it is drug resistant, and is being spread in clinics and hospitals. Research priorities include improved and point-of-care TB diagnostics; TB treatment and prevention during HIV infection, drug-resistant TB, and childhood TB; and optimization of TB and HIV program integration. With new TB diagnostics and drugs reaching approval, research must focus on effectively deploying these advancements. Research must include evaluations of individual, household, health care, and community approaches. Studies must apply implementation science to determine how to increase and adapt effective interventions to reduce TB burden in the context of HIV infection. Investment in this research will improve the lives of persons infected with HIV and contribute to efforts to reduce the global TB burden.

Non-vertical HIV transmission to children in sub-Saharan Africa

This review considers whether HIV prevalence data on children in sub-Saharan Africa support the hypothesis that blood exposures account for a large proportion of HIV infections in Africa. Data from a systematic search on HIV-infected children support two analyses. In 25 studies where the mothers' HIV status was not matched with data on each child (excluding non-representative samples of children), the observed prevalence in children in 20 studies was greater than expected from vertical transmission. The population-weighted difference – 1.3% – was approximately one-third of observed prevalence in children. In 32 studies that match HIV-positive children with HIV-negative mothers, 406 discordant mother–child pairs were identified, and in studies identifying at least five non-vertical infections in children, 17.5% of HIV-positive children had HIV-negative mothers. In discussing an important role for unsafe health care in exceptionally rapid HIV transmission in Africa, leading AIDS researchers cite low HIV prevalence in children not yet sexually active. The assumption that childhood HIV prevalence would increase with age in children, if injections transmitted HIV is shown to be erroneous; it fails to account for early mortality in HIV-positive children. Evidence of child-to-child HIV transmission supports the theory that nosocomial infections are important to the AIDS pandemic, and procedures more prevalent than blood transfusions, such as injections, are likely involved.

Behavioral mechanisms in HIV epidemiology and prevention: past, present, and future roles

In the 1980s, behavioral variations across geographically and socially defined populations were the central focus of AIDS research, and behavior change was seen as the primary means of controlling HIV epidemics. Today, biological mechanisms--especially other sexually transmitted infections, antiretroviral therapy, and male circumcision--predominate in HIV epidemiology and prevention. We describe several reasons for this shift in emphasis. Although the shift is understandable, we argue for a sustained focus on behavioral mechanisms in HIV research in order to realize the theoretical promise of interventions targeting the biological aspects of HIV risk. We also provide evidence to suggest that large reductions in HIV prevalence may be accomplished by small changes in behavior. Moreover, we contend that behavioral mechanisms will find their proper place in HIV epidemiology and prevention only when investigators adopt a conceptual model that treats prevalence as a determinant as well as an outcome of behavior and that explicitly recognizes the dynamic interdependence between behavior and other epidemiological and demographic parameters.

Sexualised space, sexual networking & the emergence of AIDS in Rakai, Uganda

This paper argues that the outbreak of the epidemic of AIDS in Rakai, Uganda, in the early 1980s was a consequence of economic change, leading to the erosion of conventional cultural checks on juvenile, female and male sexuality and the emergence and growth of sexualised spaces and sexual networking in a few remote rural hubs of economic activity which exhibited a different sexual culture from the surrounding countryside. The trading hubs developed dense local and regional sexual networks which enabled HIV to spread quickly among the "risk groups" and local people of the busiest trading towns and villages. The high degree of sexual mixing in these hubs opened up new routes for HIV to infect the general population. This paper, which shows the importance of understanding the role of the aggravated economic disparities and changing sexual culture in the onset and spread of the HIV and AIDS epidemic in Rakai, Uganda, is primarily based on in-depth interviews and focus group discussions and on the analysis of newspapers, unofficial and official documents and academic studies.

Injection drug use, unsafe medical injections, and HIV in Africa: a systematic review

The reuse of injecting equipment in clinical settings is well documented in Africa and appears to play a substantial role in generalized HIV epidemics. The U.S. and the WHO have begun to support large scale injection safety interventions, increased professional education and training programs, and the development and wider dissemination of infection control guidelines. Several African governments have also taken steps to control injecting equipment, including banning syringes that can be reused.However injection drug use (IDU), of heroin and stimulants, is a growing risk factor for acquiring HIV in the region. IDU is increasingly common among young adults in sub-Saharan Africa and is associated with high risk sex, thus linking IDU to the already well established and concentrated generalized HIV epidemics in the region. Demand reduction programs based on effective substance use education and drug treatment services are very limited, and imprisonment is more common than access to drug treatment services.Drug policies are still very punitive and there is widespread misunderstanding of and hostility to harm reduction programs e.g. needle exchange programs are almost non-existent in the region. Among injection drug users and among drug treatment patients in Africa, knowledge that needle sharing and syringe reuse transmit HIV is still very limited, in contrast with the more successfully instilled knowledge that HIV is transmitted sexually. These new injection risks will take on increased epidemiological significance over the coming decade and will require much more attention by African nations to the range of effective harm reduction tools now available in Europe, Asia, and North America.

Men who have sex with men and HIV/AIDS in sub-Saharan Africa

Globally, men who have sex with men (MSM) continue to bear a high burden of HIV infection. In sub-Saharan Africa, same-sex behaviours have been largely neglected by HIV research up to now. The results from recent studies, however, indicate the widespread existence of MSM groups across Africa, and high rates of HIV infection, HIV risk behaviour, and evidence of behavioural links between MSM and heterosexual networks have been reported. Yet most African MSM have no safe access to relevant HIV/AIDS information and services, and many African states have not begun to recognise or address the needs of these men in the context of national HIV/AIDS prevention and control programmes. The HIV/AIDS community now has considerable challenges in clarifying and addressing the needs of MSM in sub-Saharan Africa; homosexuality is illegal in most countries, and political and social hostility are endemic. An effective response to HIV/AIDS requires improved strategic information about all risk groups, including MSM. The belated response to MSM with HIV infection needs rapid and sustained national and international commitment to the development of appropriate interventions and action to reduce structural and social barriers to make these accessible.

Knowledge, attitudes to HIV/AIDS and sexual behaviour of students in a tertiary institution in south-western Nigeria

OBJECTIVE

To determine the knowledge, attitude and sexual behaviour of students in a tertiary institution in south western Nigeria with regard to HIV/AIDS.

METHODS

Descriptive cross-sectional survey conducted between January and March 2005. Information was collected from 368 students of a tertiary institution in Ede, Osun State, Nigeria. Participants were selected by a multi-stage sampling method and data obtained using a semi-structured pre-tested questionnaire.

RESULTS

Most (89.4%) respondents were aware of the existence of HIV/AIDS, and knew the aetiology, routes of transmission, signs and symptoms, and preventive measures against the disease. While a little over half (59.8%) of the respondents revealed that they could hug people with HIV/AIDS, one out of four (27.2%) stated that these persons should be isolated from the community. Less than a quarter (22.3%) of the respondents believed that they were vulnerable to HIV/AIDS. More than half (58.2%) had ever had sex; the mean age at their first sexual exposure (for all respondents) was 16.7 +/- 4.4 years. Almost half (48.2%) of the 191 currently sexually active respondents had multiple sexual partners. Of the sexually active respondents, 75.9% claimed to have ever used condoms; among these, male respondents were more likely to have ever used condoms than their female counterparts (p < 0.05).

CONCLUSION

The study revealed a gap in the knowledge of HIV/AIDS and an inappropriate sexual behaviour among respondents. Meaningful strategies, such as an innovative and culturally sensitive adolescent sexual and reproductive health programme that focuses on modification of sexual behaviour should be adopted to allow young people to prevent transmission of the HIV/AIDS virus.

Sensitivity of paediatric AIDS score vs. WHO case classification in Indian children--a retrospective study

This study was conducted at the Department of Paediatrics, Dr Ram Manohar Lohia Hospital, to test the statistical significance of existing World Health Organization (WHO) clinical case definition (CCD) for diagnosis of AIDS in areas where diagnostic resources are limited. A total of 360 cases between 18 months and 12 years of age satisfying WHO case definitions of AIDS were included in study group. Our study detected 16.66% (60) of HIV incidence in children visiting the paediatrics outpatient clinic. Twenty percent of cases manifested three major and two minor signs, which had sensitivity of 73.33%; specificity, 90.66% and positive predictive value (PPV), 61.11%. Stepwise logistic analysis identified weight loss, chronic fever >1 month and total lymphocyte count <1500 cells mm(-3) as important predictors. Eighty-six cases (23.89%) showed two major and two minor signs with sensitivity and specificity of 86.66 and 88.66%, respectively. Thus a CCD based on 13 clinical signs/symptoms was proposed for paediatric AIDS with better sensitivity and PPV than the WHO case definition but with almost similar specificity.

Biomedical interventions to prevent HIV infection: evidence, challenges, and way forward

Intensive research efforts for more than two decades have not yet resulted in an HIV vaccine of even moderate effectiveness. However, some progress has been made with other biomedical interventions, albeit on the basis of inconsistent levels of evidence. The male condom, if used correctly and consistently, has been proven in observational studies to be very effective in blocking HIV transmission during sexual intercourse; and, in three randomised trials, male circumcision was protective against HIV acquisition among men. Treatment of sexually transmitted infections, a public health intervention in its own right, has had mixed results, depending in part on the epidemic context in which the approach was assessed. Finally, oral and topical antiretroviral compounds are being assessed for their role in reduction of HIV transmission during sexual intercourse. Research on biomedical interventions poses formidable challenges. Difficulties with product adherence and the possibility of sexual disinhibition are important concerns. Biomedical interventions will need to be part of an integrative package that includes biomedical, behavioural, and structural interventions. Assessment of such multicomponent approaches with moderate effects is difficult. Issues to be considered include the nature of control groups and the effect of adherence on the true effectiveness of the intervention.

Interactions between schistosomiasis and infection with HIV-1

In many regions of the world, both schistosomiasis and HIV/AIDS are endemic, resulting in patients harbouring co-infections. Because interaction with host CD4(+) T cells is a characteristic of schistosome as well as HIV-1 infections, bi-directional disease effects may be sufficiently different from sequelae caused by either infectious agent alone to warrant alteration of public health approaches in areas of co-endemnicity. Studies published over the past decade provide useful insights into interactions between schistosomiasis and infection with HIV-1, and overall support the hypothesis that special emphasis on treatment of schistosomiasis in populations with elevated prevalence or risk of HIV-1 infection is justified.

Clinical characteristics and initial management of patients with tuberculous pericarditis in the HIV era: the Investigation of the Management of Pericarditis in Africa (IMPI Africa) registry

BACKGROUND

The incidence of tuberculous pericarditis has increased in Africa as a result of the human immunodeficiency virus (HIV) epidemic. However, the effect of HIV co-infection on clinical features and prognosis in tuberculous pericarditis is not well characterised. We have used baseline data of the Investigation of the Management of Pericarditis in Africa (IMPI Africa) registry to assess the impact of HIV co-infection on clinical presentation, diagnostic evaluation, and treatment of patients with suspected tuberculous pericarditis in sub-Saharan Africa.

METHODS

Consecutive adult patients in 15 hospitals in three countries in sub-Saharan Africa were recruited on commencement of treatment for tuberculous pericarditis, following informed consent. We recorded demographic, clinical, diagnostic and therapeutic information at baseline, and have used the chi-square test and analysis of variance to assess probabilities of significant differences (in these variables) between groups defined by HIV status.

RESULTS

A total of 185 patients were enrolled from 01 March 2004 to 31 October 2004, 147 (79.5%) of whom had effusive, 28 (15.1%) effusive-constrictive, and 10 (5.4%) constrictive or acute dry pericarditis. Seventy-four (40%) had clinical features of HIV infection. Patients with clinical HIV disease were more likely to present with dyspnoea (odds ratio [OR] 3.2, 95% confidence interval [CI] 1.4 to 7.4, P = 0.005) and electrocardiographic features of myopericarditis (OR 2.8, 95% CI 1.1 to 6.9, P = 0.03). In addition to electrocardiographic features of myopericarditis, a positive HIV serological status was associated with greater cardiomegaly (OR 3.89, 95% CI 1.34 to 11.32, P = 0.01) and haemodynamic instability (OR 9.68, 95% CI 2.09 to 44.80, P = 0.0008). However, stage of pericardial disease at diagnosis and use of diagnostic tests were not related to clinical HIV status. Similar results were obtained for serological HIV status. Most patients were treated on clinical grounds, with microbiological evidence of tuberculosis obtained in only 13 (7.0%) patients. Adjunctive corticosteroids were used in 109 (58.9%) patients, with patients having clinical HIV disease less likely to be put on them (OR 0.37, 95% CI 0.20 to 0.68). Seven patients were on antiretroviral drugs.

CONCLUSION

Patients with suspected tuberculous pericarditis and HIV infection in Africa have greater evidence of myopericarditis, dyspnoea, and haemodynamic instability. These findings, if confirmed in other studies, may suggest more intensive management of the cardiac disease is warranted in patients with HIV-associated pericardial disease.

Characteristics and presenting complaints of outpatients with undiagnosed HIV infection: potential utility in selecting subjects for HIV testing

HIV testing of individuals presenting to outpatient medical clinics has generally been based upon a selection system, with testing limited to those having signs or symptoms previously found associated with HIV-1 infection among hospitalized patients. However, little is known about the efficacy of this approach, particularly in Africa. Among patients presenting to a large outpatient infectious disease clinic in Dakar, Senegal, the utility of using specific demographic and behavioral characteristics and individual presenting complaints to identify individuals with previously undiagnosed HIV-1 or HIV-2 infection was examined. Using a simple statistical approach, a composite screening rule was estimated to identify subjects with the highest probability of testing HIV positive, ie, patients who would most benefit from HIV testing. Using the presenting complaint allows identification of 83% of HIV-infected women by testing only 35% of women presenting to the clinic. Similarly, using the presenting complaint and various demographic and behavioral characteristics, it was possible to identify 84% of HIV-infected men by screening 40% of men presenting to the clinic. This study suggests that this method might provide a cost-effective approach that permits limited screening resources to be spent in a way that maximizes individual and societal benefit.

The evolution of HIV and its consequences

Since the beginning of the AIDS epidemic in 1981, HIV-1 has demonstrated an amazing ability to mutate. HIV-1 was introduced into the human population in the early to mid twentieth century in central Africa. During ensuing decades, this extraordinary mutational capacity has resulted in the circulation of HIV-1 strains that are quite different from one another, yet still remarkably pathogenic. The potential impact of this viral diversity on treatment, monitoring,and vaccine development is discussed.

Oro-facial manifestations in paediatric HIV: a comparative study of institutionalized and hospital outpatients

The aim of the study was to compare dental caries status and the number and type of oral mucosal lesions in HIV positive children from a hospital outpatient department and an institutionalized setting. Oral examinations were performed using presumptive diagnostic criteria. The Fisher's Exact and the Mann-Whitney tests were used for statistical comparison of the two study groups. A total of 169 children were examined of whom 42% were institutionalized and 58% hospital outpatients. One institutionalized child presented with Noma. Twenty-one percent of the institutionalized population presented with molluscum contagiosum, while none of the hospital outpatients presented with this condition. Significantly more intraoral mucosal lesions were observed in the hospital compared with the institutionalized group. The most frequently encountered oral lesion was candidiasis. Pseudomembranous candidiasis was the most common type. Twice as many intraoral ulcers were recorded in the institutionalized group. Thirty-nine percent of the hospitalized patients had multiple lesions compared with 28% in the institutionalized group. Almost three quarters of both populations were caries-free. The mean DMFT was considerably higher in the hospital population. For both the permanent and primary teeth, the decayed component (D/d) made up the major part of the DMFT/dmft, followed by the missing (M/m) component. No fillings were recorded in either the primary or permanent teeth for both groups. Oral lesions are common in HIV populations and were seen in both the hospital and institutionalized groups, at high prevalence levels (63 and 45%). HIV infected children should be considered high risk for caries because of the use of chronic medications, and to receive appropriate care in terms of both treatment and services.

The chemical bases of the various AIDS epidemics: recreational drugs, anti-viral chemotherapy and malnutrition

In 1981 a new epidemic of about two-dozen heterogeneous diseases began to strike non-randomly growing numbers of male homosexuals and mostly male intravenous drug users in the US and Europe. Assuming immunodeficiency as the common denominator the US Centers for Disease Control (CDC) termed the epidemic, AIDS, for acquired immunodeficiency syndrome. From 1981-1984 leading researchers including those from the CDC proposed that recreational drug use was the cause of AIDS, because of exact correlations and of drug-specific diseases. However, in 1984 US government researchers proposed that a virus, now termed human immunodeficiency virus (HIV), is the cause of the non-random epidemics of the US and Europe but also of a new, sexually random epidemic in Africa. The virus-AIDS hypothesis was instantly accepted, but it is burdened with numerous paradoxes, none of which could be resolved by 2003: Why is there no HIV in most AIDS patients, only antibodies against it? Why would HIV take 10 years from infection to AIDS? Why is AIDS not self-limiting via antiviral immunity? Why is there no vaccine against AIDS? Why is AIDS in the US and Europe not random like other viral epidemics? Why did AIDS not rise and then decline exponentially owing to antiviral immunity like all other viral epidemics? Why is AIDS not contagious? Why would only HIV carriers get AIDS who use either recreational or anti-HIV drugs or are subject to malnutrition? Why is the mortality of HIV-antibody-positives treated with anti-HIV drugs 7-9%, but that of all (mostly untreated) HIV-positives globally is only 1.4%? Here we propose that AIDS is a collection of chemical epidemics, caused by recreational drugs, anti-HIV drugs, and malnutrition. According to this hypothesis AIDS is not contagious, not immunogenic, not treatable by vaccines or antiviral drugs, and HIV is just a passenger virus. The hypothesis explains why AIDS epidemics strike non-randomly if caused by drugs and randomly if caused by malnutrition, why they manifest in drug- and malnutrition-specific diseases, and why they are not self-limiting via anti-viral immunity. The hypothesis predicts AIDS prevention by adequate nutrition and abstaining from drugs, and even cures by treating AIDS diseases with proven medications.

Enhancement of natural killer cell activation and antibody-dependent cellular cytotoxicity by interferon-alpha and interleukin-12 in vaginal mucosae Sivmac251-infected Macaca fascicularis

We studied the innate immune system of Cynomolgus monkeys (Macaca fascicularis) experimentally infected via the vaginal mucosae with a virulent simian immunodeficiency virus isolate SIVmac251. Animals were evaluated for their natural killer (NK) cell activity, and for their antibody-dependent cellular cytotoxicity. NK cells from SIVmac251-infected macaques show impaired NK cell activity compared to cells from uninfected animals. Subsequent treatment of NK cells with interferon-a (IFN-alpha) or interleukin-12 (IL-12) alone partially restored the NK activity. However, either treatment of NK cells with both IFN-alpha and IL-12 completely reversed the impairment of cytotoxicity induced by simian immunodeficiency virus (SIV) infection. Incubation of NK cells from infected but not from uninfected monkeys with IFN-alpha and IL-12 for 8 days increased the percentage of CD16+/CD56+ cells twofold to five-fold and enhanced antibody-dependent cellular cytotoxicity (ADCC) activity. Thus IFN-alpha and IL-12 greatly enhance both the NK cell and ADCC activities of peripheral blood cells from SIVmac251-infected animals and increase the number of NK cells in longer term culture. The combined effect of IFN-alpha and IL-12 in enhancing NK cell activity may provide a novel therapeutic approach for the restoration of depressed NK cell activity observed in human immunodeficiency virus (HIV)-infected patients.

The spread and effect of HIV-1 infection in sub-Saharan Africa

Africa is the continent most severely affected by the global HIV-1 epidemic, with east and southern Africa in general more severely affected than west and central Africa. Differences in the spread of the epidemic can be accounted for by a complex interplay of sexual behaviour and biological factors that affect the probability of HIV-1 transmission per sex act. Sexual behaviour patterns are determined by cultural and socioeconomic contexts. In sub-Saharan Africa, some traditions and socioeconomic developments have contributed to the extensive spread of HIV-1 infection, including the subordinate position of women, impoverishment and decline of social services, rapid urbanisation and modernisation, and wars and conflicts. Populations in many parts of Africa are becoming trapped in a vicious circle as the HIV-1 epidemic leads to high mortality rates in young and economically productive age groups, and thus leads to further impoverishment. Interventions to control HIV-1 should not only target individuals, but also aim to change those aspects of cultural and socioeconomic context that increase the vulnerability to HIV-1 of people and communities.

The global tuberculosis situation. Progress and problems in the 20th century, prospects for the 21st century

Mycobacterium tuberculosis has been identified in prehistoric remains of humans. Despite references to TB by Hippocrates and Galen, humankind had limited understanding of and few tools to defend itself against TB until the later 19th century. Subsequently, landmark advances in the 20th century provided the means to control and prevent this disease. At the same time, epidemiological developments and fundamental problems related to human behavior, socioeconomic conditions, and political circumstances continue to thwart efforts to diminish the burden of suffering and death caused by TB. This article reviewed some of these issues including the global failure of TB control in the late 20th century, the worldwide emergence of drug-resistant TB, the extensive spread of HIV infection and its impact on TB incidence; and changing health care and political environments. The obstacles to TB control remain and will remain challenges in the coming years. Still, recent developments in immunology, biochemistry, and molecular biology suggest that new knowledge and tools are just around the corner. These will enhance the ability to conquer this microbe by the end of the current century.

CHAT oral polio vaccine was not the source of human immunodeficiency virus type 1 group M for humans

A book published in 1999 hypothesized that the scientists who worked with the CHAT type 1 attenuated poliomyelitis strain, tested in the former Belgian Congo in the late 1950s, had covertly prepared the vaccine in chimpanzee kidney cells contaminated with a simian immunodeficiency virus, which evolved into human immunodeficiency virus type 1 group M. This article summarizes the results of the investigation conducted by the author to determine the legitimacy of the accusation. Testimony by eyewitnesses, historical documents of the time, epidemiological analysis, and analysis of ancillary phylogenetic, virological, and polymerase chain reaction data all indicate that this hypothesis is false.

Are there simple measures to reduce the risk of HIV infection through blood transfusion in a Zambian district hospital?

OBJECTIVE

To quantify the potential impact of simple measures to reduce the risk of iatrogenic HIV infection through blood transfusion in a Zambian district hospital.

METHODS

Three studies were conducted at St. Francis' Hospital, Katete, Zambia: (1) From 1991 to 1995 HIV seroprevalence among all listed blood donors and the impact of proper subgroup selection were studied retrospectively; (2) the sensitivity of locally used rapid antibody assays (HIV-spot/Wellcozyme HIV 1 & 2) for the detection of HIV in donor blood and the influence of the expiration date of the tests on this sensitivity were determined prospectively from June 1993 until March 1994 by screening all consecutive surgical patients and blood donors; (3) the number of unnecessary blood transfusions was determined retrospectively from January 1995 through January 1996 and prospectively from February 1996 through March 1996, and possibilities to reduce the total number of blood transfusions were considered.

RESULTS

(1) Excluding prisoners, who have an HIV seroprevalence of 19-25%, from the donor population significantly reduces the overall HIV seroprevalence from 13-16% to 8-9% (P < 0. 01). (2) Under local circumstances the sensitivity of the used rapid antibody assays was 6.8-17.9% lower than claimed by the manufacturer. Usage of non-expired tests increased the sensitivity significantly from 88.2% to 91.7% (P < 0.05). (3) None of the 294 studied blood transfusions can be classified as inappropriate according to international standards.

CONCLUSIONS

Simple measures such as proper subgroup selection among blood donors and correct use of non-expired tests may decrease the risk of iatrogenic HIV transmission. Stricter indications for blood transfusions will not substantially reduce the number of transfusions.

Heterosexual anal intercourse: prevalence, cultural factors, and HIV infection and other health risks, Part I

Studies of heterosexual HIV transmission have consistently found anal intercourse to be a highly predictive risk factor for seroconversion. Yet most AIDS prevention messages targeted at heterosexuals, presumably influenced by cultural taboos against acknowledging this sexual practice, continue to emphasize vaginal and, increasingly, oral sex transmission. The health risks of anal sex appear to be severely underestimated by a substantial proportion of sexually active women and men in North and Latin America as well as parts of South Asia, Africa, and other regions. Among heterosexuals reported rates of condom use are nearly universally lower for anal than for vaginal intercourse. This review examines anal sex among the general population, including its prevalence in various world regions, related sociocultural factors, and other associated health problems including anorectal STDs, Hepatitis B infection, and HPV-related anal cancer in women. U.S. survey and other data suggest that, in terms of absolute numbers, approximately seven times more women than homosexual men engage in unprotected receptive anal intercourse. Research among higher risk subpopulations, including bisexual men, injecting drug users, female sex workers, inner-city adolescents, and serodiscordant heterosexual couples, indicates that persons particularly at risk of being infected by or transmitting HIV are also more likely to practice anal sex. Considering this finding, along with the much greater efficiency for HIV infection as well as lower rates of condom usage, a significant proportion of heterosexual transmission in some populations is due to anal intercourse. This typically stigmatized and hidden sexual practice must be given greater emphasis in AIDS/STD prevention, women's care, and other health promotion programs.

Incidence of HIV and sexually transmitted diseases (STD) in a cohort of HIV-negative men who have sex with men (MSM)

OBJECTIVE

To determine the prevalence of sexually transmitted diseases (STD) and incidence of and risk factors for STD, including HIV-1, among a cohort of HIV-negative men who have sex with men (MSM).

SETTING

Seattle, Washington, United States.

PARTICIPANTS

Prospective cohort of 578 HIV-negative MSM in which risk factors for acquiring a STD over 12 months follow-up were evaluated using a cumulative incidence analysis.

MAIN OUTCOME MEASURES

Baseline tests obtained were: herpes simplex virus types 1 and 2 (HSV-1 and HSV-2) Western blots, hepatitis B, and syphilis serologies; anorectal and pharyngeal Neisseria gonorrhoeae (GC) cultures; first-catch urine for leukocyte esterase (LE) and Chlamydia trachomatis (CT) ligase chain reaction (LCR). Men with a positive urine LE had urethral GC cultures obtained. The following outcomes were measured over 12 months follow-up: incident symptomatic bacterial STD (urethritis, proctitis, epididymitis), HSV-1 and HSV-2 seroconversion, and HIV-1 seroconversion. The 31 incident cases of STD (men with bacterial STD) were compared with those 489 men without symptomatic bacterial STD or seroconversion to HSV-1, HSV-2 or HIV-1 infection.

RESULTS

Bacterial STD were found in nine participants at enrollment; there were two cases of nonchlamydial urethritis, two cases of nonchlamydial epididymitis, and five cases of asymptomatic GC infection. At enrollment, HSV-2 antibodies were detected in 149 (26.0%) of 572 men and prior hepatitis B infection in 145 (34.8%) of 417 unvaccinated men. During the 1-year of follow-up, 31 men (5.7/100 person-years) had 34 episodes of a symptomatic bacterial STD syndrome (urethritis, epididymitis or proctitis). Urethritis was the most common STD syndrome, detected in 29 men, of whom 10 had GC and 19 had nongonococcal urethritis. In the 1-year of follow-up, five participants seroconverted to HIV-1 (1.3/100 person-years), four to HSV-2 (1.0/100 person-years), and seven to HSV-1 (4.3/100 person-years). Unprotected insertive anal sex [odds ratio (OR) 2.6; 95% confidence interval (CI) 1.2-5.6]; and nitrite inhalant ('poppers') use (OR, 2.3; 95% CI, 1.0-5.0) were independently associated with incident STD.

CONCLUSIONS

STD and HIV infection continue to be acquired even in a city with an overall low bacterial STD prevalence and among educated MSM receiving regular HIV screening and risk-reduction. Urethritis was the most common STD detected, and public health messages aimed at MSM need to emphasize safe insertive as well as receptive sexual practices.

[Determination of HIV protein 24 in feces of Triatoma infestans fed with blood from AIDS patients]

OBJECTIVE

To verify any possibility of the elimination of p24 in feces of Triatoma infestans, p24 being an antigen and one of the markers of HIV infection. The purpose of the study was the evaluation of any risk of contamination by laboratory staff who work with activities related to this particular insect, and also investigate any mechanism that might thus lead to the dissemination of HIV.

METHOD

Triatoma infestans were fed with p24-marked blood from 23 AIDS patients. Twenty-four and 48 hours later, their feces were examined in order to verify the presence of the antigen. The search for p24 was performed by means of the immunoenzymatic technique.

RESULT AND CONCLUSION

No protein 24 was detected in any of the samples. In accordance with the applied methodology, the purpose of showing that the elimination of p24 does not occur, was obtained. Were this question approached in other ways different results might reveal new information in terms of risks of HIV dissemination.

Heart involvement and HIV infection in African patients: determinants of survival

In Africa, recent studies have reported that HIV may exhibit a cardiac tropism. The purpose of this study was to determine if clinical features, sex, age at onset, biological or echocardiographic variables have any influence on survival of African HIV-infected patients and AIDS progression. One hundred and fifty seven consecutive HIV-seropositive patients without cardiac lesions and no other AIDS-defining illnesses underwent physical, electrocardiographic and Doppler echocardiographic examinations at the Heart of Africa Cardiovascular Centre, Lomo Medical, Kinshasa, Congo, between July 1987 and July 1994. Odds ratios were calculated to assess the influence of potential risk factors on cardiac lesions, opportunistic diseases, and death outcomes. Cardiac lesions had occurred in 87 patients (55%) during 7-year follow up. The onset of heart involvement was associated with a protection against opportunistic comorbidity. In multiple regression model, cardiac mass/volume ratio, body temperature, deceleration time, body mass index and socio-economic status were each independently associated with AIDS outcome. In a multivariate analysis the lowest socioeconomic status and the pericardial effusion were the independent predictors of death. The higher CD4 count and cardiac lesions outcome were connected with slower progression to AIDS. Dilated cardiomyopathy was associated with longer survival.

The association of herpes simplex virus type 2 (HSV-2), Haemophilus ducreyi, and syphilis with HIV infection in young men in northern Thailand

To evaluate the association between sexually transmitted diseases that commonly may cause genital ulceration and prevalent and incident HIV infections, we conducted three case control studies in a cohort of 21-year-old male military conscripts in northern Thailand. The men were evaluated at baseline in 1991 and semiannually until their discharge 2 years later. Serologic evidence of infection with herpes simplex virus type 2 (HSV-2), Haemophilus ducreyi, and HIV were more frequent at baseline in 83 men with a history of genital ulcer than in 97 men without such a history. Seropositivity to H. ducreyi (odds ratio [OR] = 3.46), HSV-2 (OR = 3.83), and syphilis (OR = 1.53) were more common in HIV-positive than HIV-negative men. Men (N = 45) who seroconverted to HIV while in the military were more often seropositive for H. ducreyi and HSV-2 before HIV seroconversion and also were more likely to seroconvert to HSV-2 and H. ducreyi during the same interval as their HIV seroconversion compared with men who remained HIV-negative. These data suggest that HSV-2 and H. ducreyi may be both markers for high-risk sexual behavior and risk factors for HIV infection among young men in Thailand.

An adenovirus-simian immunodeficiency virus env vaccine elicits humoral, cellular, and mucosal immune responses in rhesus macaques and decreases viral burden following vaginal challenge

Six female rhesus macaques were immunized orally and intranasally at 0 weeks and intratracheally at 12 weeks with an adenovirus type 5 host range mutant (Ad5hr)-simian immunodeficiency virus SIVsm env recombinant and at 24 and 36 weeks with native SIVmac251 gp120 in Syntex adjuvant. Four macaques received the Ad5hr vector and adjuvant alone; two additional controls were naive. In vivo replication of the Ad5hr wild-type and recombinant vectors occurred with detection of Ad5 DNA in stool samples and/or nasal secretions in all macaques and increases in Ad5 neutralizing antibody in 9 of 10 macaques following Ad administrations. SIV-specific neutralizing antibodies appeared after the second recombinant immunization and rose to titers > 10,000 following the second subunit boost. Immunoglobulin G (IgG) and IgA antibodies able to bind gp120 developed in nasal and rectal secretions, and SIV-specific IgGs were also observed in vaginal secretions and saliva. T-cell proliferative responses to SIV gp140 and T-helper epitopes were sporadically detected in all immunized macaques. Following vaginal challenge with SIVmac251, transient or persistent infection resulted in both immunized and control monkeys. The mean viral burden in persistently infected immunized macaques was significantly decreased in the primary infection period compared to that of control macaques. These results establish in vivo use of the Ad5hr vector, which overcomes the host range restriction of human Ads for rhesus macaques, thereby providing a new model for evaluation of Ad-based vaccines. In addition, they show that a vaccine regimen using the Ad5hr-SIV env recombinant and gp120 subunit induces strong humoral, cellular, and mucosal immunity in rhesus macaques. The reduced viral burden achieved solely with an env-based vaccine supports further development of Ad-based vaccines comprising additional viral components for immune therapy and AIDS vaccine development.

[The challenge of emergent diseases and the return to descriptive epidemiology]

The definition of emergent and re-emergent diseases, patterns of occurrence during the last 25 years, and the determinants of this occurrence are presented. The importance of descriptive epidemiology and its use in the investigation of these health problems, especially in view of epidemiologists' tendency to give less attention to it, finally, is emphasized the challenges that the emergent diseases pose for public health practice and for the methodological development of descriptive epidemiology are also set out. These challenges are considered in three fields: biosecurity, surveillance systems and descriptive epidemiology techniques.

AIDS and HIV infection in Sudanese children: a clinical and epidemiological study

HIV surveillance and screening programs were established at Khartoum Teaching Hospital (KTH) following the first identified HIV case diagnosed in a hemophiliac boy in November 1987. As of December 1995, 15 cases of symptomatic HIV infection have been observed in Sudanese children (< or = 16 years) at KTH. An HIV seroprevalence rate of 35.7% was documented in a group of 28 patients (adults and children) with various congenital coagulation defects. The postulated mode of transmission was through contaminated factor concentrate. Screening of 52,000 volunteer male blood donors (March, 1987-1989) showed an HIV-seroprevalence rate of 0.05%. Selected groups, including 1118 children admitted to KTH during the period 1985-1995, were screened for HIV infection. These included aseptic meningitis/encephalitis group (n = 52), high-risk group (n = 523), children with various chronic and malignant diseases (n = 181), and chronic blood recipients (n = 330). A group of 32 displaced homeless children who survived on the streets were also included. Overall, an HIV seroprevalence rate of 1.2% was established. Among the 15 children with symptomatic HIV infection, tuberculosis accounted for the majority of admissions (33.3%) followed by admission for recurrent infections (20.0%). Of the 13 children with nonparental mode of HIV transmission, a vertical mode was documented in 61.5%. The pattern of HIV infection in Greater Khartoum is similar to that in North Africa and the Middle East. However, the geographic influence of high endemicity in neighboring sub-Saharan countries might change it in the future.