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Sexual Risk Behavior for HIV and other sexual diseases in Burkina Faso and structure of a sexual contact network
Abstract
This study was aimed at measuring the degree distribution of the network of sexual contacts in Burkina Faso, in order to gain a better understanding of the sexual risk behaviours for HIV and other sexually transmitted diseases. It was found that the number of different sexual partners reported by males is distributed as a power law, with an exponent γ=2.9 (0.1). This is consistent with the degree distribution of a scale-free network. On the other hand, the females can be divided into two groups: the prostitutes with an average of 400 different partners per year (highly connected nodes), and females with a stable partner, having a rapidly decreasing degree distribution. Such a result may have important implications on the strategies to control sexually transmitted diseases (STD) and in particular HIV. Since scale-free networks exibit no epidemic threshold, a campaign based on the identification of infected individuals and the use of antiviral treatment of few highly connected nodes, associated to effective programs of sexual and sanitary education, can be more successful than any policy based on enlarged but random distribution of the available antiviral or barrier treatments, whose current result in term of sexual transmitted diseases has been a full failure.
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For more than a decade, most experts have assumed that more than 90% of HIV in African adults results from heterosexual transmission. In this exercise, we show how data from studies of risk factors for HIV can be used to estimate the proportion from sexual transmission, and we present our estimates.
Calculating two ways from available data, our two point estimates — we do not estimate confidence intervals — are that 25-29% of HIV incidence in African women and 30-35% in men is attributable to sexual transmission; these estimates assume 10% annual epidemic growth. These findings call for reconceptualization of research to more accurately assess routes of HIV transmission.
Public health authorities have long believed that the preponderance of AIDS cases in Africa are attributable to 'heterosexual transmission'; most people silently assume this rubric to indicate penile-vaginal intercourse only. Recent epidemiologic analyses suggest that the majority of HIV cases in sub-Saharan Africa may be due to non-sterile health care practices. The present paper reviews the anthropological, proctologic, and infectious disease literature, and argues that both homosexuality and heterosexual anal intercourse are more prevalent in Africa than has traditionally been believed. The authors hypothesize that perhaps the majority of HIV transmission not accounted for by iatrogenic exposure could be accounted for by unsuspected and unreported penile-anal intercourse. Given the authors' findings, properly conducted studies to measure this HIV transmission vector, while controlling for iatrogenic exposure confound, are clearly warranted in Africa and in countries with similar epidemiologic characteristics.
Truck drivers are a well recognized high risk population for sexually transmitted diseases. Prior to start-up of a health care program and an information/education campaign, a cross-sectional study using the unlinked, anonymous screening method was carried out to assess seroprevalence of HIV and syphilis infections in truck drivers in Bobo Dioulasso, Burkina Faso. During the month of November 1994, 236 truck drivers were recruited at a cotton-producing factory. The prevalence of HIV infection was 18,6% and the prevalence of syphilis was 9,3%. Multivariate logistic regression analysis showed a statistically significant association between HIV infection and the following factors : age under 30 years, claimed systematic use of condoms, and previous genital ulcers. These findings suggest that truck drivers are highly exposed to the risk of contracting and disseminating HIV infection due to their high mobility and the high incidence of sexually transmitted diseases among their ranks. Prevention of HIV infection in truck drivers in Burkina Faso will require education to promote systematic use of condoms at each sexual contact as well as screening and treatment of sexually transmitted diseases at truck stops.
It is obvious that the characteristics of a specific disease must be understood thoroughly in order to model that disease. Gonorrhea incidence, transmission, symptoms, complications and treatments are described in sections 1.1 and 1.2. Various current and potential control procedures for gonorrhea are described in section 1.3. Among the several basic types of models for infectious diseases described in section 1.4, it is apparent that one type is suitable for gonorrhea. A brief description of previous work on the mathematical modeling of gonorrhea is given. The concepts of the contact number and the infectee number are described in section 1.5.
S 0 3 9 9-0 7 7 X (0 3) 0 0 1 0 4-5 Co-infection hépatite C et VIH chez les femmes enceintes à Ouagadougou (Burkina Faso) Hepatitis C and HIV co-infection in pregnant women, Ouagadougou (Burkina Faso) Si l'épidémiologie du virus de l'hépatite B et du VIH est bien connue dans nos pays au Sud du Sahara, celle du virus de l'hépatite C (VHC), découvert seulement il y a une dizaine d'années, est encore très peu documentée du fait du coût élevé de ce type de sérologie. Pourtant, sa fréquence varie de 2 à 15,9 % en Afrique, avec une zone de haute endémicité en Afrique centrale ; au Burkina, elle était de 2,5 % chez les donneurs de sang [1]. Ainsi, 10 à 20 millions de personnes seraient infectées et 6 à 12 millions seraient des porteurs chroniques sur le continent. Le VHC partage avec le VIH les mêmes voies de transmission. Ce qui favorise une possibilité de co-infection. Aux USA par exemple, le VHC affecte environ un tiers des sujets VIH positifs et la co-infection est associée à un taux plus élevé de la virémie [2]. Mais dans la mesure où la trithérapie maîtrise le développement du VIH, il est impérieux de connaître le devenir à court terme de l'affection hépatique par le virus C. En outre, la transmission verticale mère-enfant existe pour les deux virus, même si elle paraît inférieure à 5 % [2], mais l'influence de la séropositivité maternelle pour le VIH accroît le risque de transmission pour le VHC. En effet, ce risque est proche de 20 % et inférieur à 3 % respec-tivement lorsque la mère est séropositive et séronégative pour le VIH [3]. Or, la prévalence du virus C est de 0,2 à 7 % chez les femmes enceintes. Le but de cette étude est de préciser le taux de prévalence des deux virus chez la femme enceinte à Ouagadougou et évoquer les problèmes liés à cette situation.
The present research was aimed to prevent mother-to-child transmission of HIV; to use RT-PCR in order to detect, 6 months after birth, infected children; and to test the antiretroviral resistance of both children and mothers in order to offer them a suitable therapy. At the Saint Camille Medical Centre, 3,127 pregnant women (aged 15–44 years) accepted to be enrolled in the mother-to-child transmission prevention proto-col that envisages: (i) Voluntary Counselling and Testing for all the pregnant women; (ii) Antire-troviral therapy for HIV positive pregnant women and for their newborns; (iii) either powdered milk feeding or short breast-feeding and RT-PCR test for their children; (iv) finally, pol gene sequencing and antiretroviral resistance identifications among HIV positive mothers and children. Among the patients, 227/3,127 HIV seropositive women were found: 221/227 HIV-1, 4/227 HIV-2, and 2/227 mixed HIV infections. The RT-PCR test allowed the detection of 3/213 (1.4%) HIV infected children: 0/109 (0%) from mothers under ARV therapy and 3/104 (2.8%) from mothers treated with Nevirapine. All children had recombinant HIV-1 strain (CRF06_CPX) with: minor PR muta-tions (M36I, K20I) and RT mutations (R211K). Among them, two twins had Non-Nucleoside Reverse Transcriptase Inhibitor mutation (Y18CY). Both mothers acquired a major PR mutation (V8IV), investigated 6 months after a single-dose of Nevirapine. Prevention by single-dose of Nevirapine reduced significantly mother-to-child transmission of HIV, but caused many mutations and resistance to antiretroviral drugs. Based on present study the antiretroviral therapy protocol, together with the artificial-feeding, might represent the ideal strategy to avoid transmission of HIV from mother-to-child.
It is important for HIV/AIDS control programmes to determine population knowledge on AIDS in order to develop appropriate Information, Education and Communication (IEC) messages. The objectives of our study were to determine the seroprevalence of HIV and syphilis among pregnant women, female prostitutes and long-distance truck drivers and to evaluate knowledge, attitudes, beliefs, and practice (KABP) with respect to the HIV/AIDS epidemic in these three groups in Burkina Faso.
We performed three cross-sectional serosurveys including face-to-face interviews on KABP between October 1994 and February 1995 in three population groups.
Overall, 1,294 pregnant women, 236 long-distance truck drivers and 426 female prostitutes were recruited. HIV seroprevalence was 8% (95% Confidence Interval (CI): 6.6-9.6) among pregnant women, 18.6% (95% CI: 13.9-24.2) among long-distance truck drivers and 58.2% (95% CI: 53.4-62.9) in female prostitutes. The prevalence of syphilis was 2.5%, 9.3% and 15%, respectively. Most pregnant women (98%), long-distance truck drivers (96%) and female prostitutes (98%) had already heard of AIDS. However, the level of knowledge of HIV transmission routes, of risk factors for HIV transmission and of available preventive measures was very low. Consequently, 41% of pregnant women, 40% of long-distance truck drivers and an alarming 61% of female prostitutes reported that they did not feel themselves at risk for HIV. In each group, high levels of knowledge on AIDS were associated with increased awareness of AIDS risk and the adoption of preventive behaviours. Level of education was associated with knowledge of AIDS and condom use. However, in the 12 months preceding the surveys, condom use was very low among pregnant women (0.1%), long-distance truck drivers (18%) and among female prostitutes (42%).
These results indicate that HIV is widespread in Burkina Faso and that there is an urgent need to develop and evaluate HIV prevention strategies in the general population and among core groups such as female prostitutes and long-distance truck drivers. Interventions must include information campaigns, condom promotion and distribution, and sexually transmitted diseases control.
Little information is available regarding human immunodeficiency virus (HIV) infection among female sex workers (FSW) in Burkina Faso, West Africa. A cross-sectional study was conducted in Ouagadougou and Bobo-Dioulasso, the 2 largest cities of the country, to determine the prevalence of HIV infection and other sexually transmitted diseases (STDs) among FSWs, and to investigate the factors which were associated with HIV infection in this population. From October to November 1994, 426 FSWs were recruited. The method of anonymous and unlinked HIV screening recommended by the World Health Organization (WHO) was used. The overall HIV seroprevalence was 58.2% (95% confidence interval: 53.4-62.9) and 52.6% of FSWs had at least one STD agent. The most common STDs were trichomoniasis (23%), syphilis (15%) and gonorrhoea (13%). In a logistic regression analysis, risk factors for HIV infection were high gravidity (> or = 2 pregnancies), low perception of personal risk of HIV infection, syphilis and the presence of genital warts. These results suggest that FSWs in Burkina Faso need better information about HIV transmission and prevention and then need better access to STD detection and management services.
One thousand three hundred and twenty-eight pregnant women with less than 32 weeks of amenorrhea received voluntary counseling and testing at Saint Camille Medical Center from May 1, 2002 to December 30, 2004. Following informed consent and pre-test counseling, HIV screening was performed in 1,202 women. According to the prevention protocol, HIV-positive women received a single dose of Nevirapine (200 mg) during their labor, while their newborn received a single dose of Nevirapine (2 mg/kg) within 72 hr from birth. HIV seroprevalence (11.2%) was higher than in the overall population. One hundred and ninty-three children were born at the end of December 2004; 53 children (27.5%) followed a short breastfeeding protocol for 4 months, while 140 (72.5%) were fed artificially. All the children underwent RT-PCR test for HIV 5-6 months after their birth: 173 (89.6%) were HIV negative whilst 20 children (10.4%) were HIV positive. Out of the 20 positive children 5/53 (9.4%) had received breast milk for 4 months, while the remaining 15/140 (10.7%) had been fed artificially (P = 0.814). Artificially fed babies (3/140 (2.1%)) and 1/53 (1.9%) of those breast fed for 4 months deceased according to mortality rate of HIV-positive children. This shows that there is no statistically significant difference (P = 0.648) between the mortality of artificially fed (3/140 or 2.1%) and breast-fed (1/53 or 1.9%) children. Artificially fed children (20/140 (14.3%)) and 5/53 (9.4%) of breast-fed children died within 6-10 months. This figure indicates that there is no significant difference between the mortality rate of artificially and that of breast-fed children (P = 0.427). Although the HIV prevention program reduced significantly the vertical transmission of HIV at Saint Camille Medical Center, the mortality of artificially fed children was still high due to gastrointestinal diseases. The HIV diagnosis by RT-PCR technique was of great help in the early identification of HIV-infected children.
To determine the prevalence of HIV infection among pregnant women in Burkina Faso and to identify factors associated with HIV infection in this population, we performed in 4 antenatal clinics in 4 urban centres located in the centre, the north, the east and the south-west of the country cross-sectional serological surveys between 7 October 1994 and 7 February 1995 using unlinked anonymous HIV screening method. In the towns included in the study more than 94% of pregnant women attend at least 2 antenatal consultations. In each centre all pregnant women attending an antenatal consultation during a 2-week period were invited to take part in a study to measure the prevalence of syphilis. Women with positive syphilis serology were offered treatment free of charge. A total of 1294 pregnant women were recruited into the study. There were no refusals. Thirty-two women (2.5%) had positive syphilis serology. The overall seroprevalence of HIV infection was 8% (95% confidence interval [CI]: 6.6-9.6). There was no evidence that the prevalence of syphilis or HIV infection varied between the 4 towns (P=0.12 and 0.52 respectively). In logistic regression analyses only the presence of syphilis infection was associated with risk of HIV (odds ratio=3.4; 95% CI: 1.4-7.9). The prevalence of syphilis among pregnant women in Burkina Faso is relatively low compared with that of HIV infection. These results suggest that HIV epidemic in Burkina Faso is important and that there is an urgent need to intensify HIV-prevention activities. The need for HIV surveillance in this sentinel population is urgent to follow the course of the epidemic and to measure the impact of interventions. One of the consequences of the high prevalence of HIV infection among pregnant women which requires greater attention in Burkina Faso is the increasing number of children who will be infected with HIV by vertical transmission.
A longitudinal study was conducted to evaluate the viral shedding present in cervicovaginal secretions of HIV-1-seropositive women receiving antiretroviral therapy. A total of 128 paired cervicovaginal and blood samples was obtained from 37 women during a median follow-up period of 21 months. A sensitive, competitive, polymerase chain reaction and a reverse transcription polymerase chain reaction were used for the simultaneous quantitation of HIV-1 proviral DNA and RNA in cervicovaginal cells and cell-free RNA in cervicovaginal secretions, as well as HIV-1 RNA in peripheral blood. The cumulative probability of detecting proviral DNA in genital secretions was significantly higher over time in women with detectable viremia than in women in whom HIV-1 RNA was persistently undetectable in plasma (< 50 copies/ml) (P = 0.028 by log-rank test). The presence and amount of proviral DNA, cell-associated RNA and cell-free RNA in the cervicovaginal secretions were positively correlated with the presence of detectable viremia or the number of HIV-1 RNA copies in plasma (Spearman rank correlation, 0.290, 0.279, and 0.305, respectively; all P < 0.01), but no correlation was found with the CD4+ cell count. In addition, vaginal infections were positively correlated with the detection of proviral DNA in cervicovaginal secretions (odds ratio, 2.60; 95% confidence interval, 1.07-5.70). However, the positive correlation between the presence and amount of HIV in cervicovaginal secretions and the viral load in plasma provides no assurance that HIV shedding does not occur in the genital tract of women with undetectable HIV-RNA in plasma.
We investigated contraceptive practices in the rural health district of Kaya in Burkina Faso with the aim of a) comparing the sociodemographic and cultural characteristics of individuals who were well and poorly informed concerning contraceptive methods; b) analyzing the pattern of use of these contraceptive methods by the populations. We carried out a two-level cluster survey by the Hendersen method. For each household investigated, the chief, his wife (or one wife selected at random in polygamous families) and an adolescent (or one adolescent selected at random if there was more than one adolescent) were interviewed. Significantly more men than women were well informed concerning contraceptive methods. Similarly, a higher proportion of male adolescents than of female adolescents were well informed concerning contraceptive methods. The individuals who were well informed concerning contraceptive methods differed from those who were not well informed in terms of age, religion, level of education and radio listening habits. The prevalence of use of contraceptive methods in this study was found to be 4 to 36%, depending on the group studied. The majority of individuals expressed an intention to use contraceptive methods in the future: 59 to 78%, depending on the group studied. The contraceptive methods chosen for current and future use were, in order: the pill, condoms and contraceptive implants and the intrauterine device. Current patterns of contraceptive use favor, in decreasing order of preference, abstinence, the pill, condoms and contraceptive implants. There was also a strong tendency for individuals to experiment with diverse contraceptive methods. Thus, in the future, there is likely to be a trend towards the abandoning of abstinence in favor of the pill, condoms and contraceptive implants. Of these newer methods, condoms are likely to be the least popular and their relegation to a lower level of importance is likely to have disastrous consequences in terms of the prevention of HIV transmission by the sexual route. The results of this study indicate that information campaigns concerning contraceptive methods should be refocused on women and adolescent girls, condom promotion and maintaining the use of the methods chosen in the population.
PIP:
On September 30, 1988, Burkina Faso had only 26 reported cases of AIDS. By March 20, 1992, there were 1263 reported cases. Burkina Faso officials focus on AIDS prevention. Heterosexual transmission of HIV predominates in Africa. There are observable behaviors, practices, and beliefs of the Mossi society in Burkina Faso which expose people to HIV or facilitate its transmission. The Mossi is a hierarchical society with the chief having absolute power. The head of the family has absolute power over the women and children. Polygamy is common. The Mossi describe their past as an earthly paradise with no AIDS. This magnificent past allows a faulty perception of one's risk. The cultural tradition of a widow marrying her husband's younger brother appears to be a risk for HIV transmission. This custom is forced on the widow because in the Mossi society a woman with no husband is nothing. If a man dies of AIDS and has infected some or all of his wives, the younger brother(s) will in turn become infected. On the other hand, a younger brother may be HIV infected and, upon marrying his deceased brother's wife or wives, he infects her or them. Uncircumcised males and females are stigmatized and marginalized in the Mossi society. Nonsterilized instruments are used to perform genital mutilations and are used on several persons. Traditional vaccinations by cutaneous scarification and treatment of sores and cutaneomucous lesions are other possible ways HIV may be transmitted among the Mossi. Preparing the cadaver is done without gloves and, in cases of AIDS, exposes the preparers to open lesions. Serious obstacles to HIV prevention campaigns are erroneous beliefs about the modes of HIV transmission, the acculturated fatalistic attitude among youth that one contracts AIDS whether or not one takes precautions, and the attitude that AIDS comes from elsewhere.
Only a limited number of studies have examined the effects of social networks on sexually transmitted diseases (STDs), although the findings of such studies would be helpful in designing more effective prevention strategies.
This study attempts (1) to determine whether there are any social network effects on STD transmission after controlling for other risk factors and (2) to explore the possible mechanisms by which social networks exert their effects.
Logistic regressions examine the effects of friendship networks on STD transmission using data drawn from the Chicago Health and Social Life Survey (CHSLS). Additional logistic regressions probe the possible mechanisms (social control versus information and dyadic versus third party) that account for how the observed effects of networks might arise.
Among people who had fewer than 13 lifetime sex partners, those with no social friends were only 0.4 times as likely to be infected as those with one or more social friends. Among people who had 13 or more lifetime partners, those with many friends (5 or 6) but weak ties to them (talking less than once a day with them) were only 0.2 times as likely to be infected as those with either fewer friends or stronger ties to their friends. Additional regressions suggest that network effects resting on dyadic control prevail among those with fewer than 13 lifetime sex partners. In contrast, network effects resting on information exchange among third parties prevail among those with 13 or more lifetime partners.
Burkina Faso has the second highest seroprevalence rate for HIV in West Africa, estimated at 6.5% of the population. Although it is one of the poorest countries in the world, antiretrovirals have been used on an extremely limited basis in Burkina Faso since at least the early 1990s. In this article we will review the evolution of antiretroviral availability in this country, describe the mechanisms by which drugs are being accessed, and review our experience with expanding antiretroviral access through drug donations in community-based settings. Finally, we will discuss some of the implications for future attempts to expand access to treatment for people living with HIV in Africa.
Five hundred and forty-seven pregnant women with less than 32 weeks of amenorrhoea, attending an antenatal clinic of St. Camille Medical Centre (SCMC) of Ouagadougou were enrolled for a hepatitis C virus (HCV) and HIV co-infection study. Fifty-eight (10.6%) were HIV positive and 18 (3.3%) were anti-HCV positive. Only seven pregnant women (i.e., 1.3%) had a documented HIV and HCV co-infection. HCV-RNA was found in 5 out of 18 (27.8%) patients, who had anti-HCV antibodies. The genotype analysis of these five patients showed that two were of 1b whereas three were of 2a genotype. Mother-to-infant transmission of the same HCV genotype (2a) was documented in only one case. High 1b prevalence has been reported in other parts of Africa, while 2a is the prevalent genotype (60%) in Burkina Faso. This genotype has a higher response rate to treatment. Serum transaminases were normal, also in presence of HCV-RNA. The higher than expected rate of co-infection in Burkina Faso seems to demonstrate a correlation between these two infections, which could influence the evolution of HIV and HCV diseases.
Two thirds of the people who have been infected by human immunodeficiency virus (HIV) in the world live in Sub-Saharan African countries. The results of a study measuring the degree distribution of the network of sexual contacts in Burkina Faso are described. Such a network is responsible for the spread of sexually transmitted diseases, and in particular of HIV. It has been found that the number of different sexual partners reported by males is a power law distribution with an exponent gamma = 2.9 (0.1). This is consistent with the degree distribution of scale-free networks. On the other hand, the females can be divided into two groups: the prostitutes with an average of 400 different partners per year, and females with a stable partner, having a rapidly decreasing degree distribution. Such a result may have important implications on the control of sexually transmitted diseases and in particular of HIV. Since scale-free networks have no epidemic threshold, a campaign based on prevention and anti-viral treatment of few highly connected nodes can be more successful than any policy based on enlarged but random distribution of the available anti-viral treatments.