Initial suboptimal CD4 reconstitution with antiretroviral therapy despite full viral suppression in a cohort of HIV-infected patients in Senegal.

OBJECTIVE: We determined the risk factors and incidence of clinical events associated with suboptimal immune reconstitution (SIR) defined by an increase in CD4 inferior to 50 cells/µL, from inclusion up to six months of antiretroviral treatment (ARVT), in patients with an undetectable viral load (<50 copies/mL). METHODS: Logistic regression and Cox's proportional hazards model were used to examine risk factors for SIR and the association between SIR and the risk of new clinical events or death, respectively after six months of ARVT. RESULTS: One hundred and two (15.5%) of the 657 patients presented with SIR. Age > 40 years (aOR = 1.74, 95% CI = 1.10-2.75), baseline CD4 ≥ 100 cells/µL (aOR = 2.06, 95% CI = 1.24-3.42), ARVT including AZT (aOR = 4.57, 95% CI=1.06-19.76), and the occurrence of a severe opportunistic infection during the first semester of ARVT (aOR = 2.38 95% CI= 1.49-3.80) were associated with SIR. After six months of ARVT and up to seven years of follow-up, 39 patients with SIR had presented with an opportunistic infection or death (rate= 9.78/100 person-years) compared to 168 with a normal recovery (rate = 7.75/100 person-years) but the difference was not statistically significant (aHR = 1.22, 95% CI = 0.85 to 1.74). CONCLUSION: SIR is less common in our country and is not associated with increased mortality or a greater incidence of opportunistic infections after six months of ARVT.

[Thirty years of tuberculosis control in Cameroon: alternating "vertical" and "horizontal" health care delivery systems]. / Trente ans de lutte antituberculeuse au Cameroun: une alternance entre systèmes d'offre de soins de santé "vertical" et "horizontal".

BACKGROUND: In sub-Saharan Africa, tuberculosis remains endemic despite reforms of health systems and the tuberculosis control organization carried out in the last decades. METHODS: We conducted a retrospective study of tuberculosis control in Cameroon from the period 2009 back to 1980. Data were collected from documents and activity reports of tuberculosis control, and interviews with managers of the National tuberculosis control program. FINDINGS: The history of tuberculosis control in Cameroon from 2009 back to 1980 can be divided into three main periods. The first period, from 1980 to 1994, corresponded to the implementation of the 'primary health care' policy. At that time, tuberculosis case management was delivered free of charge, but centralized in specialized services with a gradual and mild increase in new cases detected. The second period, from 1995 to 2000, was characterized by the implementation of the 'primary health care reorientation' policy that decentralized tuberculosis care to all health facilities, but introduced cost recovery --which came along with a dramatic drop in the number of tuberculosis cases detected. The National tuberculosis control program, established in 1996, entrusted health facilities--especially hospitals--with the responsibility of tuberculosis diagnosis and treatment, and referred to them as tuberculosis diagnosis and treatment centers. During the third period, from 2001 to 2009, owing to major support from global health initiatives, the number of tuberculosis diagnosis and treatment centers was increased (reaching 216 centers in 2009), with a significant increase of new cases detected that peaked in 2006, from where the situation started declining till 2009. CONCLUSION: Tuberculosis control indicators have never been optimal in Cameroon, despite the generally positive trend from 1980 to 2009. The strategy of tuberculosis diagnosis and treatment centers, which are essentially nested within hospitals, seems to have reached its intrinsic limitations. Better performance in tuberculosis control will henceforth require greater decentralization of tuberculosis detection and treatment to health centers. This careful decentralization will improve access for tuberculosis patients and lead to a comprehensive use of hospital technical expertise for tuberculosis care.

A national cohort of HIV-infected patients in Belgium: design and main characteristics.

In Belgium, individual laboratory and treatment data of all HIV-infected patients seen in the 9 AIDS Reference Centres and 7 AIDS Reference Laboratories are collected prospectively since 2006. We present here an analysis of patients recorded in the cohort database between 1st of January 2006 and 31st of December 2008. During that period, 11982 patients were under medical follow-up in Belgium. Sixty-one percent of the patients were male and the median age was 39.8 at the time of first recorded viral load. Among the patients whose nationality or probable mode of transmission was recorded, nearly half (48.0%) were Belgian and 38.3% originated from Sub-Saharan Africa; heterosexual contacts were reported in the majority of cases (56.0%) followed by homosexual contacts (35.3%). A total of 145 deaths were reported. Around three quarters of the patients were on ART. The median CD4 cell count rose from 470 cells/mm3 in 2006 to 501 cells/mm3 in 2008. This cohort enabled us to obtain comprehensive information on the numbers and characteristics of HIV-infected patients currently being followed up in Belgium, and on trends in antiretroviral therapy and biological results. This will serve for planning purposes, evaluation of access to care and as a source of information for further studies.

A venue-based HIV prevalence and behavioural study among men who have sex with men in Antwerp and Ghent, Flanders, Belgium, October 2009 to March 2010.

This venue-based, cross-sectional study reports on human immunodeficiency virus (HIV) prevalence and behaviour of 649 men who have sex with men (MSM) in Antwerp and Ghent, Flanders, Belgium, from October 2009 to March 2010. Using time-location sampling, we found that HIV prevalence in MSM who attended different types of venue ranged from a high of 14.5% (95% CI: 8.9­20.1; n=22 in cruising venues to 4.9% (95% CI: 1.9­7.9; n=10) in more general gay venues to 1.4% (95% CI: 0.0­3.6; n=3) at younger MSM venues. Of those who tested HIV positive (n=35, five were unaware of their HIV status or self-reported as being HIV negative. One in five respondents were of non-Belgian nationality. The results showed relatively high rates of testing for HIV (52.2%; 95 % CI: 47.8­56.2; n=288) and other sexually transmitted infections (STIs) (57.4%; 95% CI: 52.6­62.0; n=248) in the last 12 months. A majority of the men (n=233) used condoms consistently during their last anal sexual contact with a casual partner; however, HIV-positive men who were aware of their serostatus (n=30) reported less condom use with casual partners. This is the first such study in Belgium and the results constitute the evidence base for local, targeted interventions. Furthermore, our findings underscore the need for European cross-border cooperation to prevent HIV infection and other STIs among MSM.

Do behavioural differences help to explain variations in HIV prevalence in adolescents in sub-Saharan Africa?

OBJECTIVE: To compare adolescent risk factors for HIV infection in two countries with high adolescent HIV prevalence and two lower prevalence countries with the aim of identifying risk factors that may help explain differences in adolescent HIV prevalence. METHODS: Data were available from two nationally representative surveys (South Africa, Zimbabwe), two behavioural intervention trials (Tanzania, Zimbabwe) and one population-based cohort (Uganda). Data on variables known or postulated to be risk factors for HIV infection were compared. RESULTS: Few risk behaviours were markedly more common in the high HIV prevalence populations. Risk factors more common in high HIV prevalence settings were genital ulcers and discharge, and women were more likely to report older male partners. DISCUSSION: Age mixing may be an important determinate of HIV prevalence in adolescents. Potential reasons for the general lack of association between other adolescent risk factors and adolescent HIV prevalence include adult HIV prevalence, misreported behaviour, different survey methods and other unmeasured adolescent behaviours. If adult factors dominate adolescent HIV risk, it would help explain the failure of behavioural interventions targeted at adolescents and suggests future interventions should include adults.

Molecular typing of the actin gene of Trichomonas vaginalis isolates by PCR-restriction fragment length polymorphism.

Human trichomoniasis, caused by the protozoan Trichomonas vaginalis, is a highly prevalent sexually transmitted infection. However, little is known about the degree of strain variability of T. vaginalis. A reliable classification method for T. vaginalis strains would be a useful tool in the study of the epidemiology, pathogenesis and transmission of T. vaginalis. A PCR-restriction fragment length polymorphism typing method was designed and evaluated using T. vaginalis isolates obtained after culture of vaginal specimens collected in the Democratic Republic of Congo and in Zambia. The variation of the actin gene of T. vaginalis was determined for three ATCC reference strains and 151 T. vaginalis isolates. Eight different types were identified, on the basis of the digestion patterns of the amplified actin gene, with each of the restriction enzymes HindII, MseI and RsaI. It was determined that the ATCC reference strains 30001, 30240 and 50141 were of actin genotypes G, H and E, respectively. The actin genotype type E was more common in the Democratic Republic of Congo, whereas type G was the commonest type in Zambia. Translation of the nucleotide sequence showed up to three amino acid substitutions. We developed a reproducible, sensitive and specific typing method for T. vaginalis, and were able to distinguish at least eight T. vaginalis actin genotypes. Further studies are needed to evaluate the method using clinical specimens and to determine the utility of the typing method for the genotypic characterization of T. vaginalis.

Population-level effect of HSV-2 therapy on the incidence of HIV in sub-Saharan Africa.

BACKGROUND: Herpes simplex virus type 2 (HSV-2) infection increases acquisition and transmission of HIV, but the results of trials measuring the impact of HSV-2 therapy on HIV genital shedding and HIV acquisition are mixed, and the potential impact of HSV-2 therapy on the incidence of HIV at the population level is unknown. METHODS: The effects of episodic and suppressive HSV-2 therapy were simulated using the individual-level model STDSIM fitted to data from Cotonou, Benin (relatively low HIV prevalence) and Kisumu, Kenya (high HIV prevalence). Clinician- and patient-initiated episodic therapy, started when symptomatic, were assumed to reduce ulcer duration. Suppressive therapy, given regardless of symptoms, was also assumed to reduce ulcer frequency and HSV-2 infectiousness. RESULTS: Clinician-initiated episodic therapy in the general population had almost no effect on the incidence of HIV. The impact of patient-initiated therapy was higher because of earlier treatment initiation, but still low (<5%) unless symptom recognition and treatment-seeking behaviour were very high. Suppressive therapy given to female sex workers (FSW) in Kisumu had little effect on population HIV incidence. In Cotonou, suppressive therapy in FSW with high coverage and long duration reduced population HIV incidence by >20% in the long term. Impact was increased in both cities by also treating a proportion of their clients. Long-term suppressive therapy with high coverage in the general population could reduce HIV incidence by more than 30%. CONCLUSIONS: These results show that HSV-2 therapy could potentially have a population-level impact on the incidence of HIV, especially in more concentrated epidemics. However, a substantial impact requires high coverage and long duration therapy, or very high symptom recognition and treatment-seeking behaviour.

Estimates of the number of female sex workers in different regions of the world.

OBJECTIVES: To collect estimated numbers of female sex workers (FSW) and present proportions of FSW in the female population (FSW prevalence) in different regions of the world. METHODS: Subnational and national estimated numbers of FSW reported in published and unpublished literature, as well as from field investigators involved in research or interventions targeted at FSW, were collected. The proportion of FSW in the adult female population was calculated. Subnational estimates were extrapolated to national estimates if appropriate. Population surveys were scanned for proportions of adult women having sex in exchange for money or goods. RESULTS: In sub-Saharan Africa, the FSW prevalence in the capitals ranged between 0.7% and 4.3% and in other urban areas between 0.4% and 4.3%. Population surveys from this same region yielded even higher proportions of women involved in transactional sex. The national FSW prevalence in Asia ranged between 0.2% and 2.6%; in the ex-Russian Federation between 0.1% and 1.5%; in East Europe between 0.4% and 1.4%; in West Europe between 0.1% and 1.4%; and in Latin America between 0.2% and 7.4%. Estimates from rural areas were only available from one country. CONCLUSIONS: Although it is well known and accepted that FSW are a highly vulnerable group in the scope of the HIV epidemic, most countries in the world do not know the size of this population group. The estimates of the prevalence of FSW presented in this paper show how important this hard-to-reach population group is in all parts of the world.

Voluntary counseling and HIV testing for pregnant women in the Kassena-Nankana district of northern Ghana: is couple counseling the way forward?

This study reports the results of a cross-sectional questionnaire survey undertaken in the Kassena-Nankana district of Ghana to assess the perception and attitude of 270 antenatal clinic attendants towards voluntary counseling and HIV testing. It was found that although 92.6% (95% CI 88.8-95.4) of respondents indicated a willingness to get tested, only 51% (95% CI 45.0-57.2) considered HIV testing for pregnant women to be useful. Most (93.6%) indicated they would like their husbands (partners) to know the result of the test and 52.2% indicated that their husbands would be willing to accompany them to antenatal clinic (ANC) at least once during the pregnancy. The perception of the usefulness of HIV testing (OR = 8.5, 95% CI 1.8-40.0), the willingness to disclose test result to the husband (OR = 13.3, 95% CI 4.0-44.5) and perceived willingness of husband to accompany wife to antenatal clinic (OR = 5.2, 95% CI 1.4-19.8) were found to be independent predictors of a woman's willingness to get tested. The willingness to disclose test result to husband (OR 3.2, 95% CI 1.1-10.5) and knowledge of at least one mode of MTCT HIV transmission (OR = 2.1, 95% CI 1.2-3.6) were found to be independent predictors of a woman's perception that getting tested was useful. The results suggest that for pregnant women in this district, the willingness to get tested for HIV does not equate with the perception of the test's usefulness, and that spouses are likely to exert strong influence on the attitude of pregnant women towards VCT. Couple counseling facilitated through couple-friendly ANC services should be explored as strategy for the intended VCT program in this district.

Detection of Pentatrichomonas hominis DNA in biological specimens by PCR.

AIM: To develop a sensitive and specific polymerase chain reaction for the detection of Pentatrichomonas hominis in biological specimens. METHODS: Three primers, associated in two primer pairs, were designed to amplify a sequence from the SSU rRNA gene of P. hominis. The specificity of both primer pairs was established by testing DNA extractions of different Trichomonad species, protozoa, bacteria, yeasts, and human leucocytes. The analytical sensitivity was determined through testing dilutions of P. hominis trophozoites. The clinical specificity and applicability of the assay was evaluated on stool samples and self-administered vaginal swabs. CONCLUSIONS: A highly specific and sensitive PCR assay was developed. Both primer pairs performed equally well. SIGNIFICANCE AND IMPACT OF THE STUDY: The presence of P. hominis in vaginal specimens has not been reported before.

Induced abortion among women attending antenatal clinics in Yaounde, Cameroon.

OBJECTIVES: Unsafe abortion is a public health concern because of its impact on maternal morbidity and mortality. The objective of this study was to document on induced abortion in Yaounde, Cameroon. DESIGN: Cross-sectional study. SETTING: Six antenatal clinics in Yaounde, Cameroon. METHODS: Women attending antenatal clinics between October and December 1998 were included in the study and interviewed. Nulliparous were women with no previous delivery and multiparous were defined as women who had at least one previous delivery. RESULTS: Out of the 1532 women, five hundred seventy-two were nulliparous and 960 were multiparous. Of the nulliparous women 17% reported a previous abortion ever; this proportion exceeded 35% in those over 24 years. For multiparous women, the proportion who reported an abortion (between the last birth and present pregnancy) was 22%. In multivariate analysis on the group of nulliparous women, older age, having used modern contraception and having spent more than two years in the city were significantly associated with induced abortion. In the multiparous group, older age, having a full time job and antenatal clinic were significantly associated with induced abortion. CONCLUSIONS: This study shows that induced abortion is a common practice in urban Cameroon. Because of restrictive laws, a substantial proportion of these abortions are likely to be unsafe, with the risk of associated complications. There is a need for expanded comprehensive sexual and reproductive health services.

Comparison of culture and different PCR assays for detection of Trichomonas vaginalis in self collected vaginal swab specimens.

OBJECTIVES: DNA amplification techniques have become widely used for the diagnosis of sexually transmitted infections. For the detection of Trichomonas vaginalis, PCR techniques are not yet widely used despite the publication of several assays. The sensitivity and specificity of five independent primer sets were determined on self collected vaginal specimens obtained from female commercial sex workers. METHODS: Self collected specimens were obtained from symptomatic and asymptomatic women attending a female sex workers clinic in Abidjan, Côte d'Ivoire. Two vaginal specimens were collected, the first one was processed for culture and the second was processed for PCR analysis. PCR techniques for trichomonads were performed, using the primers as reported by Riley (TVA5/TVA6), Kengne (TVK3/TVK7), Madico (BTUB 9/BTUB 2), Shiao (IP1/IP2), and Mayta (TV1/TV2). An EIA amplicon detection method was designed for each of the primer sets. RESULTS: True positive specimens were defined as culture positive and/or two positive PCR results with EIA amplicon detection in any combination. According to this definition a prevalence of 20% was obtained compared to 7% obtained by culture. The PCR primer set TVK3/TVK7 gave the highest sensitivity (89.2%). Poor sensitivities were obtained with the primer sets TV1/TV2 (60.2%) and TVA5/TVA6 (63.9%). PCR showed a sensitivity improvement of 2.4% up to 12% when EIA was used for amplicon detection. CONCLUSIONS: Overall, the sensitivities of the different PCR assays resulting from this study were lower than those previously described. These findings could be the result of the nature of the specimen population and suggests a strain variability.

Role of core and bridging groups in the transmission dynamics of HIV and STIs in Cotonou, Benin, West Africa.

The potential for exposure of low and high risk women to HIV and sexually transmitted infections (STI) through unprotected sex with male clients of female sex workers in Cotonou could account for most if not all of the estimated yearly numbers of HIV infections in Cotonou women (approximately 1000). As ongoing transmission of HIV, and also of the most predominant STIs such as gonorrhoea and HSV-2, appears to be largely fuelled by transmission within core and bridging groups in Cotonou, interventions targeted at both female sex workers and their male clients remain of the utmost importance and could have a significant effect on the evolution of HIV/STI epidemics in Benin.

How many patients with a sexually transmitted infection are cured by health services? A study from Mwanza region, Tanzania.

OBJECTIVES: To estimate the proportion of symptomatic patients with a bacterial sexually transmitted infection (STI) cured by primary health care services in Mwanza Region, Tanzania, and to compare the cure rate achieved by health centres before and after the introduction of improved STI treatment services. METHODS: A model was used that describes the different hurdles patients with an STI take before they can be considered cured by the health services. The values for the input parameters for the model were taken from different studies. Data from an intervention trial as well as from a population-based study on male urethritis were used to estimate the proportion of symptomatic patients with an STI who seek care from a health centre. An observational study in four health centres where improved STI treatment services had been introduced provided estimates of the proportions of patients with an STI correctly diagnosed and treated. Patients who returned to the health centres after 1 week were interviewed about compliance. An estimate of the efficacy of treatments prescribed for STIs in health centres before the introduction of improved STI services was obtained from a study on prescription patterns for genital discharge syndrome (GDS) and genital ulcer disease (GUD). RESULTS: It was estimated that in the catchment area of health centres offering improved STI services, 51-72% of patients with STI symptoms sought care from those health centres. About 76-85% of cases were correctly diagnosed, and of these 69-80% received efficacious treatment. Compliance with full treatment was estimated at 84%. The estimated overall cure rate achieved by the health centres offering improved STI services ranged between 23 and 41%. The proportion of symptomatic STI patients who attended a health centre before improved STI services were introduced was estimated at 39%. The estimated efficacy of the treatments prescribed was 28%. The overall cure rate achieved by these health centres was less than 10%. CONCLUSIONS: When assessing the performance of STI case detection and management all steps have to be taken into account that are taken by patients with an STI before they can be considered cured by the health services. The intervention to improve STI services in Mwanza Region has resulted in an improvement of the cure rate of STIs achieved by primary health care centres.

HIV-1 subtypes and the HIV epidemics in four cities in sub-Saharan Africa.

OBJECTIVE: To describe the distribution of HIV-1 subtypes in two cities with high HIV prevalence (Kisumu, Kenya and Ndola, Zambia) and two with relatively low prevalence (Cotonou, Benin and Yaoundé, Cameroon), and to examine whether the differences in prevalence of HIV infection could be due to the predominance within the infected populations of subtypes with differing efficiency of heterosexual transmission. METHODS: For around 100 randomly selected HIV-positive sera from the general population and 60 from sex workers in each city, the HIV-1 subtype was determined in the envfragment. For between 19 and 52 of the sera from the general population and 20-32 sera from sex workers, the subtype was also determined in the gag fragment. RESULTS: Over 70% of infections in Cotonou, Yaoundé and Kisumu were with subtype A (by env). However, around one-half of subtype A infections in Cotonou and Yaoundé were found to be the circulating recombinant form CRF02_AG when the gag fragment was also examined. A large number of different HIV strains were found in Yaoundé, including some belonging to group O. Over 20% of infections in Kisumu and around 10% in Yaoundé were with isolated intersubtype recombinant forms. All but a few infections in Ndola were with subtype C and no recombinants were found. CONCLUSIONS: The pattern of distribution of subtypes that we found does not suggest that differences in circulating subtypes play a major role in explaining the differences in prevalence of HIV-1 infection between the four cities. The emergence and spread of recombinants requires close surveillance to adapt testing strategies if needed, to inform vaccine development and to ascertain their role in the future spread of HIV.

Interpreting sexual behaviour data: validity issues in the multicentre study on factors determining the differential spread of HIV in four African cities.

BACKGROUND: The main conclusion of the multicentre study on factors determining the differential spread of HIV in four African cities was that differences in sexual behaviour could not, by themselves, explain the differences in HIV prevalence between the four cities. The present paper examines three potential sources of bias that could invalidate this conclusion: (1) changes in sexual behaviour since the start of the HIV epidemics; (2) bias due to the low response rates of men; and (3) bias in reported sexual behaviour. METHODS: To assess whether there have been any changes in sexual behaviour over time, selected parameters of sexual behaviour were compared between different age groups in the four cities. The maximum likely extent of bias due to non-participation of men in Yaoundé, Kisumu and Ndola was assessed with a simulation exercise, in which records of non-participants were replaced with records of 'low activity men' in Yaoundé and 'high activity men' in Kisumu and Ndola. To assess the validity of the sexual behaviour data, internal validity checks were carried out: comparing biological data on sexually transmitted infections with reports; comparing reports of spouses; and comparing numbers of sex partners reported by men and women. A fourth method consisted of comparing the findings of the multicentre study with an external source, Demographic and Health Surveys (DHS). RESULTS: There were differences in sexual behaviour between the younger and the older age groups in all four cities but there was no evidence of a shift towards safer sexual behaviour in the high HIV prevalence cities. After simulating results for male non-participants in Yaoundé, Kisumu and Ndola, the median lifetime number of sex partners was similar in Yaoundé, Kisumu and Ndola. By testing for various sexually transmitted infections among men and women aged 15-24 years who reported that they had never had sexual intercourse, we could establish that, in all four cities, at least 1-9% of men and 6-18% of women had misreported their sexual activity. The number of non-spousal partners in the past 12 months reported by men was two to three times higher than the number reported by women, as has been found in other studies. The most consistent differences between our survey and the DHS were found in the numbers of non-spousal partners in the past 12 months reported by never-married men and women. In all four cities, participants reported more non-spousal partners in the DHS than in our survey. CONCLUSIONS: In all four cities, we found evidence that men as well as women misreported their sexual behaviour, but overall it seems that under-reporting of sexual activity was not more common or more serious in the two high HIV prevalence cities than in the two low HIV prevalence cities. We believe that the main conclusions of the multicentre study still hold.

Ecological and individual level analysis of risk factors for HIV infection in four urban populations in sub-Saharan Africa with different levels of HIV infection.

OBJECTIVE: To identify factors that could explain differences in rate of spread of HIV between different regions in sub-Saharan Africa. DESIGN: Cross-sectional study. METHODS: The study took place in two cities with a relatively low HIV prevalence (Cotonou, Benin and Yaoundé, Cameroon), and two cities with a high HIV prevalence (Kisumu, Kenya and Ndola, Zambia). In each of these cities, a representative sample was taken of about 1000 men and 1000 women aged 15-49 years. Consenting men and women were interviewed about their socio-demographic background and sexual behaviour; and were tested for HIV, herpes simplex virus type 2 (HSV-2), syphilis, Chlamydia trachomatis and Neisseria gonorrhoea infection, and (women only) Trichomonas vaginalis. Analysis of risk factors for HIV infection was carried out for each city and each sex separately. Adjusted odds ratios (aOR) were obtained by multivariate logistic regression. RESULTS: The prevalence of HIV infection in sexually active men was 3.9% in Cotonou, 4.4% in Yaoundé, 21.1% in Kisumu, and 25.4% in Ndola. For women, the corresponding figures were 4.0, 8.4, 31.6 and 35.1%. High-risk sexual behaviour was not more common in the high HIV prevalence cities than in the low HIV prevalence cities, but HSV-2 infection and lack of circumcision were consistently more prevalent in the high HIV prevalence cities than in the low HIV prevalence cities. In multivariate analysis, the association between HIV infection and sexual behavioural factors was variable across the four cities. Syphilis was associated with HIV infection in Ndola in men [aOR = 2.7, 95% confidence interval (CI) = 1.5-4.91 and in women (aOR = 1.7, 95% CI = 1.1-2.6). HSV-2 infection was strongly associated with HIV infection in all four cities and in both sexes (aOR ranging between 4.4 and 8.0). Circumcision had a strong protective effect against the acquisition of HIV by men in Kisumu (aOR = 0.25, 95% CI = 0.12-0.52). In Ndola, no association was found between circumcision and HIV infection but sample sizes were too small to fully adjust for confounding. CONCLUSION: The strong association between HIV and HSV-2 and male circumcision, and the distribution of the risk factors, led us to conclude that differences in efficiency of HIV transmission as mediated by biological factors outweigh differences in sexual behaviour in explaining the variation in rate of spread of HIV between the four cities.

Male circumcision and HIV infection in four cities in sub-Saharan Africa.

OBJECTIVES: To explore the role of male circumcision in the spread of HIV infection in four urban populations in sub-Saharan Africa. DESIGN AND METHODS: A cross-sectional population based study was conducted in four cities in sub-Saharan Africa with different levels of HIV infection. HIV prevalence among adults was relatively low in Cotonou (Benin) and in Yaoundé (Cameroon), and exceeded 25% in Kisumu (Kenya) and in Ndola (Zambia). In each city, a random sample was taken of men and women aged 15-49 years from the general population. Consenting study participants were interviewed about their sociodemographic characteristics and their sexual behaviour, and were tested for HIV, herpes simplex virus type 2, syphilis, gonorrhoea and chlamydial infection. Men underwent a genital examination. RESULTS: In Cotonou and in Yaoundé, the two low HIV prevalence cities, 99% of men were circumcised. In Kisumu 27.5% of men were circumcised, and in Ndola this proportion was 9%. In Kisumu, the prevalence of HIV infection was 9.9% among circumcised men and 26.6% among uncircumcised men. After controlling for socio-demographic characteristics, sexual behaviour and other sexually transmitted infections, the protective effect of male circumcision remained with an adjusted odds ratio of 0.26 (95% confidence interval = 0.12-0.56). In Ndola, the prevalence of HIV infection was 25.0% in circumcised men and 26.0% in uncircumcised men. The power was insufficient to adjust for any differences in sexual behaviour. CONCLUSIONS: The differences in epidemic spread of HIV are likely to be due to differences in the probability of transmission of HIV during sexual exposure as well as differences in sexual behaviour. Male circumcision is one of the factors influencing the transmission of HIV during sexual intercourse, and this study confirms the population level association between HIV and lack of male circumcision, as well as a strong individual level association in Kisumu, the only city with sufficient power to analyze this association.

Comparison of key parameters of sexual behaviour in four African urban populations with different levels of HIV infection.

OBJECTIVE: To explore whether differences in sexual behaviour could explain differences in the rate of spread of HIV in four urban populations in Africa. METHODS: A cross-sectional, population-based study was conducted in two cities where the prevalence of HIV among adults exceeded 20% (Kisumu, Kenya and Ndola, Zambia) and two cities with a much lower HIV prevalence among adults (Cotonou, Benin and Yaoundé, Cameroon). In each of these cities, approximately 1000 men and 1000 women, aged 15-49 years, were randomly selected from the general population. Consenting men and women were interviewed about their sociodemographic characteristics and sexual behaviour, including characteristics of spouses and of non-spousal partners. Key parameters of sexual behaviour were compared between the four cities. RESULTS: On average, women in the high HIV prevalence cities had their sexual debut earlier than in the other cities. Men and women in Kisumu and Ndola got married earlier than men and women in Cotonou and Yaoundé. High rates of partner change, contacts with sex workers, concurrent partnerships and large age differences between partners were no more common in the two high HIV prevalence cities than in the two low HIV prevalence cities. CONCLUSIONS: In these four African populations, differences in reported sexual behaviour could not explain the differences in rate of spread of HIV. In all four cities, high-risk sexual behaviour patterns were identified.