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Risk Factors for HIV-2 Seropositivity Among Older People in Guinea-Bissau. A Search for the Early History of HIV-2 Infection
Abstract
Because the seroprevalence of HIV-2 has been shown to be high in older age groups, we conducted a survey of all persons aged 50 years or over in two districts in Bissau, investigating the presence of HIV antibodies and possible risk factors for HIV infection with a particular emphasis on age, the impact of the war of independence (1963-74), traditional marital and extramarital sex patterns, blood contact and contact with monkeys. In 670 participants, the HIV-2 prevalence was 14.3%; 16.1% in women and 12.3% in men. The HIV-1 prevalence was only 0.5% (3/670). The HIV-2 prevalence peaked for men in the 60-69 years age group, and for women in the 50-59 years age group, declining markedly in the following age group for both men and women (OR = 0.09 (0.01-0.51), OR = 0.37 (0.15-0.82), respectively). This pattern could be due to differential mortality for HIV-2 infected individuals or to a cohort effect for a generation who were sexually active at the time of the war of independence in the 1960s and early 1970s in Bissau. Supporting the link with the colonial army, women who had had sex with a white man had a higher seroprevalence (OR = 3.63 (1.12-11.24)). The ethnic group indigenous to Bissau city had a much lower prevalence, but demographic and cultural risk factors such as marital status, religion, education and having lived outside Bissau were not associated with HIV-2. In the multivariate analyses for women, variables related to extramarital sex or prostitution (having sex with a white man, having lived in Senegal, not living with husband, and not marrying first sexual partner) were associated with higher risk. For men, previous spouses who had died or had divorced were associated with higher prevalence. Having married the first sexual partner was protective against HIV-2 infection for both men (OR = 0.29 (0.09-0.76)) and women (OR = 0.19 (0.04-1.00)). Hospitalizations, possibly due to transfusions, tended to be associated with higher risk, but only for women (OR = 1.83 (0.97-3.48)). The focus of the HIV-2 epidemic in Guinea-Bissau is likely to be endogenous, and the war of independence and the colonial army with its associated prostitution may have played an important part in propagating the virus.
... Wars and parenteral transmission have been hypothesized to have played a leading role in the early dissemination of HIV-2. Several authors pointed out the independence war of Guinea-Bissau (1963-74) as having potentially given a boost to HIV-2, by increasing sexual [28] and/or parenteral [23,29] transmission. Age cohort effects and data on parenteral exposure have been invoked to support these views [23,28,29]. ...
... Several authors pointed out the independence war of Guinea-Bissau (1963-74) as having potentially given a boost to HIV-2, by increasing sexual [28] and/or parenteral [23,29] transmission. Age cohort effects and data on parenteral exposure have been invoked to support these views [23,28,29]. ...
... Risk factors for HIV-2 positive status have been repeatedly shown to be the same as for HIV-1 positivity: being a CSW [21,42,43], contacts with CSWs [21,28,44], sexual promiscuity, single, or divorced status [24,45], genital ulcer disease [21,43,44,46], lack of MC [21,46,47], transfusions [23,24,42,45], injections [20,29]. Yet, to our knowledge, no study has attempted to associate HIV-2 prevalence with MC frequency. ...
Background:
Epidemic HIV-2 (groups A and B) emerged in humans circa 1930-40. Its closest ancestors are SIVsmm infecting sooty mangabeys from southwestern Côte d'Ivoire. The earliest large-scale serological surveys of HIV-2 in West Africa (1985-91) show a patchy spread. Côte d'Ivoire and Guinea-Bissau had the highest prevalence rates by then, and phylogeographical analysis suggests they were the earliest epicenters. Wars and parenteral transmission have been hypothesized to have promoted HIV-2 spread. Male circumcision (MC) is known to correlate negatively with HIV-1 prevalence in Africa, but studies examining this issue for HIV-2 are lacking.
Methods:
We reviewed published HIV-2 serosurveys for 30 cities of all West African countries and obtained credible estimates of real prevalence through Bayesian estimation. We estimated past MC rates of 218 West African ethnic groups, based on ethnographic literature and fieldwork. We collected demographic tables specifying the ethnic partition in cities. Uncertainty was incorporated by defining plausible ranges of parameters (e.g. timing of introduction, proportion circumcised). We generated 1,000 sets of past MC rates per city using Latin Hypercube Sampling with different parameter combinations, and explored the correlation between HIV-2 prevalence and estimated MC rate (both logit-transformed) in the 1,000 replicates.
Results and conclusions:
Our survey reveals that, in the early 20th century, MC was far less common and geographically more variable than nowadays. HIV-2 prevalence in 1985-91 and MC rates in 1950 were negatively correlated (Spearman rho = -0.546, IQR: -0.553--0.546, p≤0.0021). Guinea-Bissau and Côte d'Ivoire cities had markedly lower MC rates. In addition, MC was uncommon in rural southwestern Côte d'Ivoire in 1930.The differential HIV-2 spread in West Africa correlates with different historical MC rates. We suggest HIV-2 only formed early substantial foci in cities with substantial uncircumcised populations. Lack of MC in rural areas exposed to bushmeat may have had a role in successful HIV-2 emergence.
... HIV-2 epidemiological studies outside of Guinea-Bissau are rare and limited to the neighbouring countries of Senegal and The Gambia where the epidemics have been similarly in decline [5,6]. early spread of HIV-2 through an increase in prostitution and expansion of medical infrastructure [3,19]. Greater access to vaccinations and blood transfusions likely facilitated the iatrogenic spread of HIV-2 through needle reuse and unscreened blood [19][20][21]. ...
... early spread of HIV-2 through an increase in prostitution and expansion of medical infrastructure [3,19]. Greater access to vaccinations and blood transfusions likely facilitated the iatrogenic spread of HIV-2 through needle reuse and unscreened blood [19][20][21]. Following the war, prostitution probably receded and hygienic medical practices became more widespread. ...
... Despite the marked reduction in HIV-2 prevalence since the late-1980s, the future of the HIV-2 epidemic in Guinea-Bissau remains unclear. In 2007, infection amongst young adults was low (<1% amongst ages [15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34] [4]. However, infection has remained prevalent amongst older adults (12% amongst over 45 years) [4], susceptibility of women is believed to increase with age [23] and it has been suggested that HIV-2 may persist as an infection of the elderly [13]. ...
This article predicts the future epidemiology of HIV-2 in Caió, a rural region of Guinea Bissau; and investigates whether HIV-2, which has halved in prevalence between 1990 and 2007 and is now almost absent in young adults in Caió, can persist as an infection of the elderly.
A mathematical model of the spread of HIV-2 was tailored to the epidemic in Caió, a village in Guinea-Bissau.
An age-stratified difference equation model of HIV-2 transmission was fitted to age-stratified HIV-2 incidence and prevalence data from surveys conducted in Caió in 1990, 1997 and 2007. A stochastic version of the same model was used to make projections.
HIV-2 infection is predicted to continue to rapidly decline in Caió such that new infections will cease and prevalence will reach low levels (e.g. below 0.1%) within a few decades. HIV-2 is not predicted to persist in the elderly.
HIV-2 is predicted go extinct in Caió during the second half of this century.This is an open-access article distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License, where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially. http://creativecommons.org/licenses/by-nc-nd/4.0.
... This high dose was used because of recent reports of praziquantel resistance in travelers [7] . Because praziquantel is less effective against the juvenile forms of schistosoma [3, 8], our policy is to administer it 13 months after the last exposure. For 2 of our patients who received concomitant steroid and praziquantel treatment during the acute phase of disease, repeated praziquantel treatment was given 3 months after exposure. ...
... The prevalence of HIV-2 infection is also high in European countries that have socioeconomic relations with this region, such as Portugal and France123456. All evidence points to Guinea-Bissau as the epicenter of HIV-2 infection [7, 8]—in particular to a small area around the Canchungo Medical Centre [7]. Spread of HIV-2 seems to have occurred after 1960– 1970, but recent reports show that the interspecies transmission of HIV-2 may have happened as early as 1924 or as late as 1956 [7, 8]. ...
... All evidence points to Guinea-Bissau as the epicenter of HIV-2 infection [7, 8]—in particular to a small area around the Canchungo Medical Centre [7]. Spread of HIV-2 seems to have occurred after 1960– 1970, but recent reports show that the interspecies transmission of HIV-2 may have happened as early as 1924 or as late as 1956 [7, 8]. Very likely, the colonial war (1961–1974) contributed to the spread of HIV-2 in Guinea-Bissau, through sexual contacts and blood transfusions as a result of war injuries [1,678. ...
... All evidence points to Guinea-Bissau as the epicenter of HIV-2 infection [7,8]-in particular to a small area around the Canchungo Medical Centre [7]. Spread of HIV-2 seems to have occurred after 1960-1970, but recent reports show that the interspecies transmission of HIV-2 may have happened as early as 1924 or as late as 1956 [7,8]. ...
... All evidence points to Guinea-Bissau as the epicenter of HIV-2 infection [7,8]-in particular to a small area around the Canchungo Medical Centre [7]. Spread of HIV-2 seems to have occurred after 1960-1970, but recent reports show that the interspecies transmission of HIV-2 may have happened as early as 1924 or as late as 1956 [7,8]. Very likely, the colonial war (1961)(1962)(1963)(1964)(1965)(1966)(1967)(1968)(1969)(1970)(1971)(1972)(1973)(1974) contributed to the spread of HIV-2 in Guinea-Bissau, through sexual contacts and blood transfusions as a result of war injuries [1,[6][7][8]. ...
... Spread of HIV-2 seems to have occurred after 1960-1970, but recent reports show that the interspecies transmission of HIV-2 may have happened as early as 1924 or as late as 1956 [7,8]. Very likely, the colonial war (1961)(1962)(1963)(1964)(1965)(1966)(1967)(1968)(1969)(1970)(1971)(1972)(1973)(1974) contributed to the spread of HIV-2 in Guinea-Bissau, through sexual contacts and blood transfusions as a result of war injuries [1,[6][7][8]. At the end of the war, in 1974, Portuguese soldiers and Guinean refugees arrived in Portugal, where HIV-2 infection spread by sexual contact and blood products, prior to the universal HIV screening. ...
... 4,6 These findings are consistent with data from Guinea-Bissau, where HIV-2 seroprevalence was higher in older age groups. 7,8 This pattern can be explained by a cohort effect for a generation that was sexually active at the time of the independence war or needed health care due to war injuries or other causes. 8 The Guinea-Bissau independence war began in 1961 and continued until 1974. ...
... 7,8 This pattern can be explained by a cohort effect for a generation that was sexually active at the time of the independence war or needed health care due to war injuries or other causes. 8 The Guinea-Bissau independence war began in 1961 and continued until 1974. The war in Guinea-Bissau may have had a critical role in the early dissemination of HIV-2, due to soldier migrations, high rates of prostitution, vaccination campaigns, and other health-care actions. ...
... There is evidence that both sexual and blood-borne HIV-2 transmission increased during this period. 8 All these factors may explain not only the epidemic situation between 1955 and 1970, suggested by the study of Lemey et al, but also the HIV-2 prevalence decline in recent decades. [8][9][10] At the beginning of the 1990s, HIV-2 infection accounted for between 10% and 12% of AIDS cases in Portugal; at present HIV-2 accounts for 3·8% of AIDS cases. ...
... The origin of HIV-2 is due to an event of zoonotic transmission from simian immunodeficiency virus (SIV) from sooty mangabey (7)(8)(9) occurred during the first half of the twentieth century, followed by an initiation possible epidemic in Guinea Bissau, this coincides with the development of its war of independence (1963)(1964)(1965)(1966)(1967)(1968)(1969)(1970)(1971)(1972)(1973)(1974) (10) and epidemiological factors that favored its expansion (11). ...
... Estimating of Origin and Evolutionary History of Human Immunodeficiency Virus Type 2 in Cuba Bissau, it has been hypothesized that the war of independence made in that country, a former Portuguese colony, in the period 1963-1974, was the epicenter of the beginning of the epidemic through the spread of this virus by the Portuguese army (11). Other factors played a role in the initiation epidemic during this period, as were the increase of access to blood transfusions not researched, the increased prostitution in the region, and the ritual of female circumcision and mass vaccination campaigns (10,24,25). ...
... The impact of the Portuguese colonial war on the spread of HIV infection is unclear. Some authors point out that the epidemiological link between HIV-2 and Portugal, initiated during the presence of the colonial army, was recognized with the first cases in Europe in Portuguese veterans (Poulsen, Aaby, Jensen, & Dias, 2000). Although the occurrence of HIV infection was unknown for young people who were in military service and for drug addicts at that time, the risks were high (DGS, 2018) without any incidence or prevalence. ...
... namely, the consumption of legal and illegal drugs(Calado, 2016). Portuguese studies acknowledge that the colonial war between 1961-1974 and the returnee movement may have contributed to the spread of infection through sexual contacts, blood transfusions due to war wounds, and population miscegenation(Poulsen, Aaby, Jensen, & Dias, 2000). Concluding the discussion of the analysis of multiple responses emphasizes the greater use of communication technologies by young people compared to other age groups. ...
Summary
Generations of young people, adults and the elderly have or have had different ways of acquiring knowledge about HIV / AIDS. The accessibility of information, the evolution of information technology, or the sexualized connotation, can influence knowledge in the various generations.
Objective: describe the knowledge about HIV / AIDS among college students and family predecessors.
Method: quantitative, descriptive, cross-sectional study. Convenience sample of 147 participants recruited from students and their families. A knowledge scale of eighteen items was applied. Ethical principles cautioned, project with registration nº13009 in the Ethics Committee of the University of Évora.
Results: Through analysis of multiple responses it was observed that the most important source of information is television. Most participants reveal knowledge about HIV / AIDS. Women have more knowledge. There are significant inter-generational differences, exhibiting the youngsters the highest level of knowledge.
Conclusion: university students' knowledge about HIV / AIDS, reflecting their family background and academic development, is the support of interventions in the academic community.
Keywords: Knowledge, generation effect, HIV / AIDS, nursing, nursing students, infection, technology, family
... -The HIV-1 emerged in western Africa soon after an intense episode of slavery [12,18] in which the renunciation to defend oneself was experienced as the best survival strategy under the submission conditions imposed by the masters. The HIV-2 emergence is also related to a war context [6,19]. ...
... Concerning HIV-2, Poulsen [19] and Lemey [6] observe that the beginnings of the epidemic in Guinea-Bissau coincided with the Independence War (1963)(1964)(1965)(1966)(1967)(1968)(1969)(1970)(1971)(1972)(1973)(1974) and suggest that the socio-cultural changes linked to the war had a major impact on the HIV-2 epidemic. It is obvious that in war conditions, the renunciation of violence (the disarmament concept) is deeply desired by a significant part of the civil population. ...
Korzybski's general semantics recommends considering living beings as organisms-as-a-whole in their environment. Our cognitive abilities, specific to the human species, have thus to be taken into account. In this framework we establish a semantic similarity between particular stressful events of the 20th century and AIDS in which the immune-deficiency-caused is semiotically seen as a biological state of disarmament of the organism. It then appears that: These observations suggest that AIDS could benefit from some collusion by the neuro-immune system because of positive learning of the semiotic concept of disarmament, thus making the terrain favorable to the germ in response to intense stress. The disease would then result from a conditioning process based on semiotics and involve some confusion at the level of the unconscious cognitive system between disarmament toward outside the body and disarmament toward inside the body. This hypothesis is discussed within a multidisciplinary perspective considering the specificities of our modern lifestyles, the cybernetic ability of signs to control metabolism and behavior, and the recent advances of epigenetics and cognition sciences. This hypothesis may explain the multiple cross-species transmissions of the immunodeficiency virus into humans during the 20th century. Further research is suggested for evaluating this hypothesis.
... Our study findings also found a negative association between age ranges of adult to middle aged individuals, and HIV-2 infection when compared with young adults but did not reach statistical significance. This was inconsistent with findings from Guinea Bissau where HIV-2 prevalence peaked in men (60-69 years) and women (50-59 years) [18]. This pattern could be due to differential mortality for HIV-2 infected individuals or to a cohort effect for a generation who were sexually active at the time of the war of independence in the 1960s and early 1970s in Bissau. ...
Introduction:
the focus of antiretroviral therapy (ART) in Zambia has been on HIV-1. However, some patients are infected with HIV-2 or both. HIV-2 is resistant to non-nucleoside reverse transcriptase inhibitors (NNRTIs), drugs used for HIV-1. Therefore, this study sought to determine the seroprevalence of HIV-2 or dual infection in HIV infected individuals and compare the treatment outcomes associated with HIV subtype in patients taking NNRTI-based first line cART at the University Teaching Hospitals (UTH).
Methods:
this was a cross- sectional study, we collected data from the Virological Impact of Switching from Efavirenz and Nevirapine based first-line cART regimens to Dolutegravir (VISEND) study being conducted at UTH. Ninety six individuals were included in the study. Descriptive and inferential statistics were performed. Logistic regression was used to assess the relationship between treatment outcomes and HIV type.
Results:
the proportion of HIV 1 and 2 co-infected patients was 5.2% (95% CI 2%-12%). The mean age was 46 years ± 2 years with 60 (62.5%) being females. The median viral load was 1.3 log 10 copies/ml, IQR 0-1.7 log 10 copies/ml and the median absolute CD4+ T cell count increased from 231 to 463 cells/mm3 (p < 0.001) after being on cART for one year or more. The study did not report any associations between treatment outcomes and HIV type (p > 0.05).
Conclusion:
there is a small proportion of patients that are HIV 1 and 2 co-infected but are on an NNRTI-based cART regimen, drugs that are not active against HIV-2. This, however, does not seem to significantly affect the patient´s virological or immunological treatment outcome.
... The underlying reasons for this decline in HIV-2 prevalence is not known. However, it is possible that the high HIV-2 prevalence seen during the 1980s was a result of high levels of commercial sex work and blood transfusions during the war of independence from 1963 to 1974 and that the decline in prevalence reflects the low rates of sexual and vertical transmission that is associated with HIV-2 infection [19][20][21]. ...
Despite advances in the treatment quality of HIV throughout the world, several countries are still facing numerous obstacles in delivering HIV treatment at a sufficiently high quality, putting patients' lives in jeopardy. The aim of this status article is to give an overview of HIV treatment outcomes in the West African country, Guinea-Bissau, and to assess how newer treatment strategies such as long-acting injectable drugs or an HIV cure may limit or stop the HIV epidemic in this politically unstable and low-resource setting. Several HIV cohorts in Guinea-Bissau have been established and are used as platforms for epidemiological, virological, immunological and clinical studies often with a special focus on HIV-2, which is prevalent in the country. The Bandim Health Project, a demographic surveillance site, has performed epidemiological HIV surveys since 1987 among an urban population in the capital Bissau. The Police cohort, an occupational cohort of police officers, has enabled analyses of persons seroconverting with estimated times of seroconversion among HIV-1 and HIV-2-infected individuals, allowing incidence measurements while the Bissau HIV Cohort and a newer Nationwide HIV Cohort have provided clinical data on large numbers of HIV-infected patients. The HIV cohorts in Guinea-Bissau are unique platforms for research and represent real life in many African countries. Poor adherence, lack of HIV viral load measurements, inadequate laboratory facilities, high rates of loss to follow-up, mortality, treatment failure and resistance development, are just some of the challenges faced putting the goal of "90-90-90″ for Guinea-Bissau well out of reach by 2020. Maintaining undetectable viral loads on treatment as a prerequisite of a cure strategy seems not possible at the moment. Thinking beyond one-pill-once-a-day, long-acting antiretroviral treatment options such as injectable drugs or implants may be a better treatment option in settings like Guinea-Bissau and may even pave the way for an HIV cure. If the delivery of antiretroviral treatment in sub-Saharan Africa in a sustainable way for the future should be improved by focusing on existing treatment options or through focusing on new treatment options remains to be determined.
... Since the year 1980s, HIV-2 infection has been reported in Portugal, probably spreading from Guinea-Bissau where the highest prevalence is registered (up to 8 -10%) during the war of independence through contacts between colonial army and sex-workers [81]. In Italy attention regarding this neglected infection recently increased because of the migratory effect, leading a case of HIV-2 in a migrant individual in the Asylum Seekers Centre (ASC) as well as some cases in foreigners and native citizens in 2013 [9,11]. ...
Human immunodeficiency virus type 2 (HIV-2) was first isolated in West Africa but the number of diagnosed infections is rising in western countries due to migration and international travels. This prompts for an increased surveillance by health authorities and improved diagnostic assays. This review summarizes the advances on our understanding of the transmission, clinical presentation, antiretroviral therapy, diagnostic tests, molecular epidemiology and historical dispersal patterns of HIV-2 infection.
... HIV-2 is assumed to originate from Guinea-Bissau with a possible transition from the simian immunodeficiency virus somewhere between 1955 and 1970 [10]. HIV-2 may have reached a high prevalence ratio because of a rapid spread during the war of independence from 1963 to 1974 [11]. Commercial sex work is known to be associated with conflicts, thus possibly contributing to the spread of the virus [12]. ...
Objective:
Although Guinea-Bissau has the world's highest prevalence of HIV-2, it has been decreasing since 1987. Meanwhile, the prevalence of HIV-1 has been increasing. We describe both the prevalence and changes in incidence of HIV-2 and HIV-1 during the last 30 years of observation in the capital Bissau in Guinea-Bissau.
Methods:
A total of 3125 adults living in 412 houses in Bissau were eligible for inclusion in the present cross-sectional survey conducted from November 2014 to February 2016. All participants had a questionnaire filled out and a blood sample taken. Results were compared with previous surveys.
Results:
Of the 3125 eligible adults, 2601 (83.2%) individuals participated. The overall prevalence of HIV decreased from 8.6% (218/2548) in 2006 to 6.7% (173/2601) in 2016 with an age-adjusted and sex-adjusted prevalence ratio (aPR) of 0.71 (95% CI 0.59-0.85). Including HIV-1/2 dual infections, a decrease in the overall prevalence of HIV-2 from 4.4% (112/2548) to 2.8% (72/2601) was observed with an aPR of 0.55 (95% CI 0.41-0.73). The overall prevalence of HIV-1 decreased from 4.6% (118/2548) to 4% (104/2601) with an aPR of 0.81 (95% CI 0.63-1.05). Incidence rates for HIV-2 and HIV-1, estimated for 815 individuals, decreased from 0.24 to 0.09 and from 0.50 to 0.40 per 100 person-years of observation, respectively, in the periods between 1996-2006 and 2006-2016.
Conclusion:
The prevalence of HIV-2 continues to decrease, whereas the prevalence of HIV-1 showed sign of stabilization. The results observed may be explained by a lower pathogenicity of HIV-2 and changes in risk behavior.
... Our study population was relatively homogeneous and two different clinicians independently assessed the presence of smallpox vaccine scar. The diameter of the biggest smallpox vaccine scar found in our study was concordant with previously published findings [6,7,19,20]. We also collected information on occupation, education level and other comorbidities that might influence this association. ...
We examined the association between a history of smallpox vaccination and immune activation (IA) in a population of antiretroviral therapy-naïve people living with HIV (PLHIV). A cross-sectional study was conducted in Senegal from July 2015 to March 2017. Smallpox vaccination was ascertained by the presence of smallpox vaccine scar and IA by the plasma level of β -2-microglobulin ( β 2m). The association was analysed using logistic regression and linear regression models. The study population comprised 101 PLHIV born before 1980 with a median age of 47 years (interquartile range (IQR) = 42–55); 57·4% were women. Smallpox vaccine scar was present in 65·3% and the median β 2m level was 2·59 mg/l (IQR = 2·06–3·86). After adjustment, the presence of smallpox vaccine scar was not associated with a β 2m level ⩾2·59 mg/l (adjusted odds ratio 0·94; 95% confidence interval 0·32–2·77). This result was confirmed by the linear regression model. Our study does not find any association between the presence of smallpox vaccine scar and the β 2m level and does not support any association between a previous smallpox vaccination and HIV disease progression. In this study, IA is not a significant determinant of the reported non-targeted effect of smallpox vaccination in PLHIV.
... By contrast, HIV-2 group A is prevalent throughout west Africa (17,23,51). Much of the previous literature has focused on a possible origin of HIV-2 group A towards the west of the sooty mangabey range because of the very high prevalence of HIV-2 group A in rural Guinea Bissau, which is believed to have resulted from the social, cultural, and health care changes associated with the war of independence in the late 1960s (41,55). However, the clustering of HIV-2 group A with SIVsmm strains from the Taï Forest, particularly evident in env, suggests that group A, as well as group B, originated in the east of the sooty mangabey range. ...
Simian immunodeficiency virus of sooty mangabeys (SIVsmm) is recognized as the progenitor of human immunodeficiency virus type 2 (HIV-2) and has been transmitted to humans on multiple occasions, yet the epidemiology and genetic diversity of SIVsmm infection in wild-living populations remain largely unknown. Here, we report the first molecular epidemiological survey of SIVsmm in a community of similar to 120 free-ranging sooty mangabeys in the Tai Forest, Cote d'Ivoire. Fecal samples (n = 39) were collected from 35 habituated animals (27 females and 8 males) and tested for SIVsmm virion RNA (vRNA). Viral gag (800 bp) and/or env (490 bp) sequences were amplified from 11 different individuals (eight females and three males). Based on the sensitivity of fecal vRNA detection and the numbers of samples analyzed, the prevalence of SIVsmm infection was estimated to be 59% (95% confidence interval, 0.35 to 0.88). Behavioral data collected from this community indicated that SIVsmm infection occurred preferentially in high-ranking females. Phylogenetic analysis of gag and env sequences revealed an extraordinary degree of genetic diversity, including evidence for frequent recombination events in both the recent and distant past. Some sooty mangabeys harbored near-identical viruses (< 2% interstrain distance), indicating epidemiologically linked infections. These transmissions were identified by microsatellite analyses to involve both related (mother/daughter) and unrelated individuals, thus providing evidence for vertical and horizontal transmission in the wild. Finally, evolutionary tree analyses revealed significant clustering of the Tai SIVsmm strains with five of the eight recognized groups of HIV-2, including the epidemic groups A and B, thus pointing to a likely geographic origin of these human infections in the eastern part of the sooty mangabey range.
... Previous studies have found that HIV-2 seropositive patients are older, but also more likely to be female than HIV-1 seropositive patients. [1,24,25] An earlier study performed at the same site showed a significantly higher percentage of women than men were HIV-2 seropositive and that HIV-1 seropositive patients were more likely to be male than female. [22] In accordance with our results, a study from Burkina Faso showed that HIV-1 and HIV 1/2 dual seropositive patients had a lower baseline CD4 count than HIV-2 seropositive. ...
Background:
Better understanding of HIV-2 infection is likely to affect the patient care in areas where HIV-2 is prevalent. In this study, we aimed to characterize the clinical presentations among HIV-1, HIV-2 and HIV-1/2 dual seropositive patients.
Methods:
In a cross-sectional study, newly diagnosed HIV patients attending the HIV outpatient clinic at Hospital Nacional Simão Mendes in Guinea-Bissau were enrolled. Demographical and clinical data were collected and compared between HIV-1, HIV-2 and HIV-1/2 dual seropositive patients.
Results:
A total of 169 patients (76% HIV-1, 17% HIV-2 and 6% HIV 1/2) were included in the study between 21 March 2012 and 14 December 2012. HIV-1 seropositive patients were younger than HIV-2 and HIV-1/2 seropositive patients, but no difference in sex was observed. Patients with HIV-1 and HIV-1/2 had a lower baseline CD4 cell count than HIV-2 seropositive patients (median CD4 cell count 185, 198 and 404 cells/μl, respectively (p value 0.001 and 0.05). HIV-1 seropositive patients had a lower BMI and a higher prevalence of weight loss, skin rash and productive cough than HIV-2 seropositive patients (p value 0.03, 0.002, 0.03 and 0.04). Only four cases (2%) of pulmonary tuberculosis (TB) were diagnosed. One patient (1/96, 1%) was tested positive for cryptococcal antigen.
Conclusion:
HIV-1 and HIV-1/2 seropositive patients have lower CD4 cell counts than HIV-2 seropositive patients when diagnosed with HIV with only minor clinical and demographic differences among groups. Few patients were diagnosed with TB and cryptococcal disease was not found to be a major opportunistic infection among newly diagnosed HIV patients.
... In general, we found a higher proportion of females to be infected with HIV-2 or dually infected with HIV-1/2 than men, which is in line with trends in previous studies from Guinea-Bissau [35,36]. This finding may reflect the greater efficacy of transmission from men to women. ...
Objectives:
Several studies have reported conflicting effects of sex on HIV-1 infection. We describe differences in baseline characteristics and assess the impact of sex on HIV progression among patients at a clinic with many HIV-2 and dually infected patients.
Methods:
The study utilized a retrospective cohort of treatment-naïve adults at the largest HIV clinic in Guinea-Bissau from June 6, 2005, to December 1, 2013. Baseline characteristics were assessed and the patients followed until death, transfer, loss to follow-up, or June 1, 2014. We estimated the time from the first clinic visit until initiation of ART, death, or loss to follow-up using Cox proportional hazard models.
Results:
A total of 5,694 patients were included in the study, 3,702 women (65%) and 1,992 men (35%). Women were more likely than men to be infected with HIV-2 (19% vs. 15%, p<0.01) or dually infected with HIV-1/2 (11% vs. 9%, p=0.02). For all HIV types, women were younger (median 35 vs. 40 years), less likely to have schooling (55% vs. 77%) or to be married (46% vs. 67%), and had higher baseline CD4 cell counts (median 214 vs. 178 cells/μl). Men had a higher age-adjusted mortality rate (hazard rate ratio (HRR) 1.29, 95% confidence interval (CI) 1.09-1.52) and were more often lost to follow-up (HRR 1.27, 95% CI 1.17-1.39).
Conclusion:
Significant differences exist between HIV-infected men and women regardless of HIV type. Men seek treatment at a later stage and, despite better socioeconomic status, have higher mortality and loss to follow-up than women. This article is protected by copyright. All rights reserved.
... By contrast, HIV-2 group A is prevalent throughout west Africa (17,23,51). Much of the previous literature has focused on a possible origin of HIV-2 group A towards the west of the sooty mangabey range because of the very high prevalence of HIV-2 group A in rural Guinea Bissau, which is believed to have resulted from the social, cultural, and health care changes associated with the war of independence in the late 1960s (41,55). However, the clustering of HIV-2 group A with SIVsmm strains from the Taï Forest, particularly evident in env, suggests that group A, as well as group B, originated in the east of the sooty mangabey range. ...
... By contrast, HIV-2 group A is prevalent throughout west Africa (17,23,51). Much of the previous literature has focused on a possible origin of HIV-2 group A towards the west of the sooty mangabey range because of the very high prevalence of HIV-2 group A in rural Guinea Bissau, which is believed to have resulted from the social, cultural, and health care changes associated with the war of independence in the late 1960s (41,55). However, the clustering of HIV-2 group A with SIVsmm strains from the Taï Forest, particularly evident in env, suggests that group A, as well as group B, originated in the east of the sooty mangabey range. ...
Simian immunodeficiency virus of sooty mangabeys (SIVsmm) is recognized as the progenitor of human immunodeficiency virus type 2 (HIV-2) and has been transmitted to humans on multiple occasions, yet the epidemiology and genetic diversity of SIVsmm infection in wild-living populations remain largely unknown. Here, we report the first molecular epidemiological survey of SIVsmm in a community of 120 free-ranging sooty mangabeys in the Taı¨ForestTaı¨Taı¨Forest, Côte d'Ivoire. Fecal samples (n 39) were collected from 35 habituated animals (27 females and 8 males) and tested for SIVsmm virion RNA (vRNA). Viral gag (800 bp) and/or env (490 bp) sequences were amplified from 11 different individuals (eight females and three males). Based on the sensitivity of fecal vRNA detection and the numbers of samples analyzed, the prevalence of SIVsmm infection was estimated to be 59% (95% confidence interval, 0.35 to 0.88). Behavioral data collected from this community indicated that SIVsmm infection occurred preferentially in high-ranking females. Phylogenetic analysis of gag and env sequences revealed an extraordinary degree of genetic diversity, including evidence for frequent recombination events in both the recent and distant past. Some sooty mangabeys harbored near-identical viruses (<2% interstrain distance), indicating epidemiologically linked infections. These transmissions were identified by microsatellite analyses to involve both related (mother/daughter) and unrelated individuals, thus providing evidence for vertical and horizontal transmission in the wild. Finally, evolutionary tree analyses revealed significant clustering of the Taı¨SIVsmmTaı¨Taı¨SIVsmm strains with five of the eight recognized groups of HIV-2, including the epidemic groups A and B, thus pointing to a likely geographic origin of these human infections in the eastern part of the sooty mangabey range.
... Like HIV-1, however, HIV-2 is also closely related to a strain of Simian Immunodeficiency Virus, classified as SIV sm , harboured by the Sooty Mangabey monkeys indigenous to West Africa [52]. A reconstruction of the HIV-2 lineage puts the likely location of SIV sm crossing species to establish the HIV-2 disease in the West African country of Guinea-Bissau around 1940; however, the disease only experienced rapid exponential growth, establishing itself as an epidemic, during the period 1955-1970 [111]. This period coincides with Guinea-Bissau's war for independence which most likely created the social conditions necessary for the rapid spread of the disease [83]. ...
... The HIV-2 prevalence increases with age both among women and men 2,10,11 . Population based studies in Guinea-Bissau have shown peak prevalence rates around 60 years of age and it has been suggested that a cohort effect as a result of high transmission during the war of liberation in Guinea-Bissau some 30 years ago may be a reason for the higher prevalence rates in the older age groups 12,13 . More recent data indicate, though, that the HIV-2 prevalence in Guinea-Bissau now is declining, as observed among men in a community study 12 and also in pregnant women in Bissau 14 (Fig. 1). ...
HIV-1 and HIV-2 infections have important differences in epidemiology, clinical progression and transmission. Studies of the less transmissible and pathogenic HIV-2 have revealed some intriguing facts, indicating that it is less prone to replicate and perhaps can evoke a more efficient or long-lasting immune response than HIV-1 in the human host. Several crucial aspects of HIV-2 infection are still insufficiently characterised. However, there is now convincing evidence that plasma viral load is considerably lower for HIV-2 than for HIV-1, despite similar proviral (DNA) loads for the two viruses. There are reports on lower levels of apoptosis for HIV-2, possibly indicating a lower level of harmful immune activation. Several studies have also shown that vigorous HIV-2 specific immune responses can be detected, especially during the asymptomatic phase of HIV-2 infection. This includes humoral as well as cell-mediated immunity (CMI). The neutralising antibody response appears to be broader and the CMI may be more efficient for HIV-2 as compared to HIV-1. However, comparative studies in the same population groups on HIV-1 and HIV-2 immunity are scarce and difficult to perform. Nevertheless, by increasing our knowledge about how HIV-2 is contained to a higher degree than HIV-1, clinically as well as epidemiologically, we may gain knowledge that is useful in a wider perspective in our struggle to curb the devastating HIV/AIDS epidemic.
... In contrast, the proportion of individuals with HIV-1 infections in the age group of 15-29 years old (17.2%) was much higher than the corresponding proportion of HIV-2-infected subjects (7.0%), highlighting the need for prevention programs aimed towards younger people. These data are also consistent with previous studies conducted in other West African countries that observed a higher HIV-2 frequency among individuals over 49 years and a higher HIV-1 prevalence among younger individuals [30][31][32]. Lower frequency of children infected by vertical transmission was observed for HIV-2 (2.3%) compared with HIV-1 (16.0%) infected individuals, as described for other countries where both types circulate [33,34]. All HIV-2 samples belonged to the predominant group A, as previously described in Cape Verde [18] and other West African countries [35,36]. ...
HIV-1 and HIV-2 have been detected in Cape Verde since 1987, but little is known regarding the genetic diversity of these viruses in this archipelago, located near the West African coast. In this study, we characterized the molecular epidemiology of HIV-1 and HIV-2 and described the occurrence of drug resistance mutations (DRM) among antiretroviral therapy naïve (ARTn) patients and patients under treatment (ARTexp) from different Cape Verde islands. Blood samples, socio-demographic and clinical-laboratory data were obtained from 221 HIV-positive individuals during 2010-2011. Phylogenetic and bootscan analyses of the pol region (1300 bp) were performed for viral subtyping. HIV-1 and HIV-2 DRM were evaluated for ARTn and ARTexp patients using the Stanford HIV Database and HIV-GRADE e.V. Algorithm Homepage, respectively. Among the 221 patients (169 [76.5%] HIV-1, 43 [19.5%] HIV-2 and 9 [4.1%] HIV-1/HIV-2 co-infections), 67% were female. The median ages were 34 (IQR = 1-75) and 47 (IQR = 12-84) for HIV-1 and HIV-2, respectively. HIV-1 infections were due to subtypes G (36.6%), CRF02_AG (30.6%), F1 (9.7%), URFs (10.4%), B (5.2%), CRF05_DF (3.0%), C (2.2%), CRF06_cpx (0.7%), CRF25_cpx (0.7%) and CRF49_cpx (0.7%), whereas all HIV-2 infections belonged to group A. Transmitted DRM (TDRM) was observed in 3.4% (2/58) of ARTn HIV-1-infected patients (1.7% NRTI, 1.7% NNRTI), but not among those with HIV-2. Among ARTexp patients, DRM was observed in 47.8% (33/69) of HIV-1 (37.7% NRTI, 37.7% NNRTI, 7.4% PI, 33.3% for two classes) and 17.6% (3/17) of HIV-2-infections (17.6% NRTI, 11.8% PI, 11.8% both). This study indicates that Cape Verde has a complex and unique HIV-1 molecular epidemiological scenario dominated by HIV-1 subtypes G, CRF02_AG and F1 and HIV-2 subtype A. The occurrence of TDRM and the relatively high level of DRM among treated patients are of concern. Continuous monitoring of patients on ART, including genotyping, are public policies to be implemented.
... Previous studies have reported mean/median age of HIV-2 positive patients to be higher than that of HIV-1. [8,15,21] Similar findings are observed in the present study [ Table 2]. This may be due to the fact that there can be a delay in HIV-2 infected individuals seeking diagnosis and treatment because of the low transmissibility and slower disease progression of HIV-2. ...
The choice of antiretroviral therapy for HIV-2 differs from that for HIV-1, underscoring the importance of differentiating between the two.
The current study was planned to find out the prevalence of HIV-2 infection at our center and to find out the utility of the current diagnostic algorithm in identifying the type of HIV infection.
Retrospective analysis in a tertiary care teaching institute over a period of three years.
All patients diagnosed as HIV infected using NACO/WHO HIV testing strategy III were included in the study. They were classified as HIV-1 infected, HIV-2 infected and HIV-1 and HIV-2 co-infected based on their test results. For discordant samples, immunoblotting result from National Reference Laboratory was considered as final.
Comparison between HIV-1, HIV-2 and HIV-1+2 positive groups for age, gender, route of transmission was made using chi squared test. P value < 0.05 was considered as significant.
Of the total of 66,708 patients tested, 5,238 (7.9%) were positive for HIV antibodies. 7.62%, 0.14%, 0.08% and 0.004% were HIV-1, HIV-2, HIV-1 and HIV-2 co-infected and HIV type indeterminate (HIV-1 Indeterminate, 2+) respectively. The current algorithm could not differentiate between the types of HIV infection (as HIV-1 or HIV-2) in 63 (1.2%) cases.
In areas like the Indian subcontinent, where epidemic of both HIV-1 and HIV-2 infections are ongoing, it is important to modify the current diagnostic algorithms to diagnose and confirm HIV-2 infections.
... Another reason could be attributed to the spread of HIV-2 during the war of independence in the 1960s and early 1970s in Guinea-Bissau, when HIV-2 already existed in Guinea-Bissau [18]. It has been suggested that transmission of HIV-2 then might have been driven by multiple mechanisms, such as inoculation campaigns, non-sterile surgical procedures or injections, blood transfusions and sexual transmission [19]. None of the neighbouring countries had a similar period of prolonged armed conflict during the sixties and the seventies. ...
BACKGROUND: HIV and other sexually transmitted infections are a growing problem in the military personnel of Africa, and information about this problem in Guinea-Bissau is lacking. The aims of this study were to determine the prevalence and trends of the HIV epidemics in the military forces of Guinea Bissau and to explore possible risk factors for HIV infection. METHODOLOGY: Repeated cross-sectional surveys of HIV-1 and HIV-2 were conducted between 1992 and 2005, and knowledge, sexual behaviour and risk factors for HIV-1 and HIV-2 in military personnel in Guinea-Bissau were assessed. RESULTS: The seroprevalence of HIV-1, HIV-2 and HIV-1+HIV-2 dual reactivity was 1.1%, 8.4% and 0.1% in 1992-95, and in 2005 7.7%, 5.1% and 1.9%, respectively. Both the increase of HIV-1 and the decline of HIV-2 between 1992-95 and 2005 were significant when adjusted for age (p < 0.001 for both changes). Only a minority did not know how HIV transmits, but sexual risk taking was high. Several significant risk factors were found in univariate analyses for HIV-1 and HIV-2, but the only risk factor that remained significant after multivariate regression analysis was previous contact with a prostitute among HIV-1-positive subjects (single and dually reactive) (p < 0.01). CONCLUSION: The increasing trend of HIV-1 and the high risky sexual behavior illustrate the need for improvement in HIV/AIDS prevention efforts among military personnel in Guinea Bissau. (Less)
... In the late 1980s, HIV-2 prevalence was 8-10% in the adult population with over 15% infection in older individuals, in both urban [28] and rural [29] areas. Increased sexual risk behavior during the war of independence (1963)(1964)(1965)(1966)(1967)(1968)(1969)(1970)(1971)(1972)(1973)(1974) and iatrogenic spread may have been factors that enhanced the epidemic in Guinea-Bissau [27,[30][31][32]. Emigration from West Africa to Europe accounts for the great majority of HIV-2 infections observed in Europe [33], particularly in countries with links to West Africa such as Portugal, France and the UK [34][35][36][37]. ...
HIV-1 and HIV-2 are two related retroviruses and, in regions where both infections are endemic, HIV-1/2 dual infection can occur. Several important questions arise about the interplay between these two viruses in a single host, including: what is the potential for HIV-1–HIV-2 recombinants to form, are there synergistic or inhibitory mechanisms that result in distinct viral replication dynamics when compared with HIV-1 or HIV-2 monoinfected individuals and what are the factors to consider when choosing antiretroviral regimes in HIV-1/2 dual-infected individuals? We summarize the relevant evidence to answer these questions, as well as indentify trends in prevalence and how the natural history of HIV-1/2 dual infection differs from that of HIV-1 or HIV-2 monoinfection. The epidemiological and in vitro evidence pertaining to the question of whether HIV-2 infection may protect against HIV-1 superinfection will also be addressed.
... Molecular clock analysis favours the hypothesis of a zoonotic transmission during the first half of the 20 th century, followed by an epidemic dissemination during the 1960s. The independence war of Guinea-Bissau between 1963 and 1974 offered the circumstances favouring human transmissions (Poulsen et al. 2000; Gomes et al. 2003). Genetic variability between HIV-2 groups, and between strains of the same group is important. ...
... Another reason could be attributed to the spread of HIV-2 during the war of independence in the 1960s and early 1970s in Guinea-Bissau, when HIV-2 already existed in Guinea-Bissau [18]. It has been suggested that transmission of HIV-2 then might have been driven by multiple mechanisms, such as inoculation campaigns, non-sterile surgical procedures or injections, blood transfusions and sexual transmission [19]. None of the neighbouring countries had a similar period of prolonged armed conflict during the sixties and the seventies. ...
HIV and other sexually transmitted infections are a growing problem in the military personnel of Africa, and information about this problem in Guinea-Bissau is lacking. The aims of this study were to determine the prevalence and trends of the HIV epidemics in the military forces of Guinea Bissau and to explore possible risk factors for HIV infection.
Repeated cross-sectional surveys of HIV-1 and HIV-2 were conducted between 1992 and 2005, and knowledge, sexual behaviour and risk factors for HIV-1 and HIV-2 in military personnel in Guinea-Bissau were assessed.
The seroprevalence of HIV-1, HIV-2 and HIV-1+HIV-2 dual reactivity was 1.1%, 8.4% and 0.1% in 1992-95, and in 2005 7.7%, 5.1% and 1.9%, respectively. Both the increase of HIV-1 and the decline of HIV-2 between 1992-95 and 2005 were significant when adjusted for age (p < 0.001 for both changes). Only a minority did not know how HIV transmits, but sexual risk taking was high. Several significant risk factors were found in univariate analyses for HIV-1 and HIV-2, but the only risk factor that remained significant after multivariate regression analysis was previous contact with a prostitute among HIV-1-positive subjects (single and dually reactive) (p < 0.01).
The increasing trend of HIV-1 and the high risky sexual behavior illustrate the need for improvement in HIV/AIDS prevention efforts among military personnel in Guinea Bissau.
... Therefore, it seems unlikely that safer sex practices have played an important role in this decline. An increase in risk behavior and blood transfusions during the War of Independence (1963-74) is thought to have enabled the spread of HIV-2 [32,33]. A concomitant iatrogenic spread through vaccination campaigns and large-scale parenteral treatment programs might have also contributed to the initial spread [34,35]. ...
HTLV-1 is endemic in Guinea-Bissau, and the highest prevalence in the adult population (5.2%) was observed in a rural area, Caió, in 1990. HIV-1 and HIV-2 are both prevalent in this area as well. Cross-sectional associations have been reported for HTLV-1 with HIV infection, but the trends in prevalence of HTLV-1 and HIV associations are largely unknown, especially in Sub Saharan Africa. In the current study, data from three cross-sectional community surveys performed in 1990, 1997 and 2007, were used to assess changes in HTLV-1 prevalence, incidence and its associations with HIV-1 and HIV-2 and potential risk factors.
HTLV-1 prevalence was 5.2% in 1990, 5.9% in 1997 and 4.6% in 2007. Prevalence was higher among women than men in all 3 surveys and increased with age. The Odds Ratio (OR) of being infected with HTLV-1 was significantly higher for HIV positive subjects in all surveys after adjustment for potential confounding factors. The risk of HTLV-1 infection was higher in subjects with an HTLV-1 positive mother versus an uninfected mother (OR 4.6, CI 2.6-8.0). The HTLV-1 incidence was stable between 1990-1997 (Incidence Rate (IR) 1.8/1,000 pyo) and 1997-2007 (IR 1.6/1,000 pyo) (Incidence Rate Ratio (IRR) 0.9, CI 0.4-1.7). The incidence of HTLV-1 among HIV-positive individuals was higher compared to HIV negative individuals (IRR 2.5, CI 1.0-6.2), while the HIV incidence did not differ by HTLV-1 status (IRR 1.2, CI 0.5-2.7).
To our knowledge, this is the largest community based study that has reported on HTLV-1 prevalence and associations with HIV. HTLV-1 is endemic in this rural community in West Africa with a stable incidence and a high prevalence. The prevalence increases with age and is higher in women than men. HTLV-1 infection is associated with HIV infection, and longitudinal data indicate HIV infection may be a risk factor for acquiring HTLV-1, but not vice versa. Mother to child transmission is likely to contribute to the epidemic.
... Guinea-Bissau has had the highest recorded figures of HIV-2 prevalence globally [3]. There is suggestion that parenteral transmission played a role in the spread of HIV-2 in the early epidemic [4], though a community-based study in the capital Bissau points out sexual transmission as the most important [5]. ...
To study prevalence and incidence of HIV-1 and HIV-2 between 1990 and 2007 and to examine impact of the civil war in 1998-1999. We also wanted to investigate possible interaction between HIV-1 and HIV-2.
Open prospective cohort study of 4592 police officers in Guinea-Bissau, West Africa.
Analysis of HIV-1 and HIV-2 prevalence and incidence divided in 2-3 years time strata.
HIV-1 prevalence (including HIV-1/HIV-2 dual reactivity) increased gradually from 0.6 to 3.6% before the war and was 9.5% in the first serosurvey after the war. HIV-1 incidence more than doubled during and shortly after the war, from 0.50 to 1.22 per 100 person-years. Both prevalence and incidence of HIV-1 decreased in the following periods after the war. HIV-2 prevalence decreased from 13.4 to 6.2% during the entire study period and HIV-2 incidence decreased from 1.38 to 0.18 per 100 person-years. Adjusted incidence rate ratios of HIV-1 incidence in HIV-2-positive participants compared with HIV-negative participants ranged from 1.02 to 1.18 (not significant) depending on the confounding variables included.
HIV-1 has increased, whereas HIV-2 has decreased and the risk of acquiring HIV-1 is now more than four times higher as compared with HIV-2. The civil war in 1998-1999 appears to have induced a temporary increase in HIV-1 transmission, but now a stabilization of HIV-1 incidence and prevalence seems to have taken place. There was no evidence of a protective effect of HIV-2 against HIV-1 infection.
... Infection patterns appear to have been affected by the 1998-99 civil war, which introduced a significant amount of HIV-1 to the country. The consequences of this change are still under analysis 19 . ...
The article reviews academic literature in the social sciences and health on the problems and challenges of STD/AIDS prevention in Portuguese-speaking African countries. Based on a bibliographic survey of the SciELO, PubMed, and Sociological Abstracts databases between 1997 and 2007, the research under review was organized into two groups, according to content. The first group of studies sought to understand STD/AIDS vulnerability among social groups by examining local cultural and socioeconomic factors as related to gender dynamics, sexuality, color/race, religion and health care. The second group encompassed critical assessments of shortcomings in the STD/AIDS educational messages delivered by governments and international agencies. Attention is called to the way in which the presence of traditional medicine systems and the occurrence of civil wars in the post-colonial period impact the STD/AIDS epidemic in the African countries under study.
... Some authors have hypothesized that the war for independence against the Portuguese colonial forces may help to explain the epidemic in Guinea-Bissau. 22 We sought to identify social, demographic, and behavioural factors that might be associated with HIV infection at the population and the individual level so that we could explain its heterogeneity at our three sites. No factors, however, were found to be a risk factor in Caio or to distinguish Caio from the two Senegalese populations with low levels of infection. ...
... Although the zoonotic episode that was responsible for the introduction of HIV-1 into human host had apparently occurred about two decades earlier than that of HIV-2 [127,141,217,228], both viruses had begun to spread nearly at the same time, somewhere between 1950 and 1970 [141,156,202]. In other words, the distinct epidemiologic profile of HIV-1 and HIV-2 cannot be attributed to a significantly different timescale for epidemic history in human population. ...
Human immunodeficiency virus type 1 (HIV-1) and type 2 (HIV-2) are the causative agents of Acquired Immunodeficiency Syndrome (AIDS). Without therapeutic intervention, HIV-1 or HIV-2 infections in humans are characterized by a gradual and irreversible immunologic failure that ultimately leads to the onset of a severe immunodeficiency that constitutes the hallmark of AIDS. In the last two decades AIDS has evolved into a global epidemic affecting millions of persons worldwide. Although sharing several identical properties, HIV-1 and HIV-2 have shown some important differences in vivo. In fact, a significant amount of epidemiologic, clinical and virologic data suggest that HIV-2 is in general less virulent than HIV-1. This reduced virulence is revealed by the longer asymptomatic period and the smaller transmission rate that characteristically are observed in HIV-2 infection. In this context, studies using HIV-2 as a model of a naturally less pathogenic infection could bring important new insights to HIV pathogenesis opening to new strategies to vaccines or therapeutic design. The reasons underlying the reduced pathogenicity of HIV-2 are still essentially unknown and surely are the outcome of a combination of distinct factors. In this review we will discuss the importance and the possible implications in HIV-2 pathogenesis, particularly during the asymptomatic period, of a less fitted interaction between viral envelope glycoproteins and cellular receptors that have been described in the way HIV-2 and HIV-1 use these receptors.
... By contrast, HIV-2 group A is prevalent throughout west Africa (17,23,51). Much of the previous literature has focused on a possible origin of HIV-2 group A towards the west of the sooty mangabey range because of the very high prevalence of HIV-2 group A in rural Guinea Bissau, which is believed to have resulted from the social, cultural, and health care changes associated with the war of independence in the late 1960s (41,55). However, the clustering of HIV-2 group A with SIVsmm strains from the Taï Forest, particularly evident in env, suggests that group A, as well as group B, originated in the east of the sooty mangabey range. ...
Simian immunodeficiency virus of sooty mangabeys (SIVsmm) is recognized as the progenitor of human immunodeficiency virus type 2 (HIV-2) and has been transmitted to humans on multiple occasions, yet the epidemiology and genetic diversity of SIVsmm infection in wild-living populations remain largely unknown. Here, we report the first molecular epidemiological survey of SIVsmm in a community of approximately 120 free-ranging sooty mangabeys in the Taï Forest, Côte d'Ivoire. Fecal samples (n = 39) were collected from 35 habituated animals (27 females and 8 males) and tested for SIVsmm virion RNA (vRNA). Viral gag (800 bp) and/or env (490 bp) sequences were amplified from 11 different individuals (eight females and three males). Based on the sensitivity of fecal vRNA detection and the numbers of samples analyzed, the prevalence of SIVsmm infection was estimated to be 59% (95% confidence interval, 0.35 to 0.88). Behavioral data collected from this community indicated that SIVsmm infection occurred preferentially in high-ranking females. Phylogenetic analysis of gag and env sequences revealed an extraordinary degree of genetic diversity, including evidence for frequent recombination events in both the recent and distant past. Some sooty mangabeys harbored near-identical viruses (<2% interstrain distance), indicating epidemiologically linked infections. These transmissions were identified by microsatellite analyses to involve both related (mother/daughter) and unrelated individuals, thus providing evidence for vertical and horizontal transmission in the wild. Finally, evolutionary tree analyses revealed significant clustering of the Taï SIVsmm strains with five of the eight recognized groups of HIV-2, including the epidemic groups A and B, thus pointing to a likely geographic origin of these human infections in the eastern part of the sooty mangabey range.
... This question is not resolved. 18,19 CD4 counts were not available for one-third of HIV infected patients, but it is not evident in which direction this bias might have worked. Even if one would assume that all of those had CD4 counts .200 ...
The HIV-1 epidemic in West Africa is characterized by a slower rise than that in Eastern and Southern Africa. The HIV-2 epidemic in West Africa may be declining, but few long-term data exist.
In a research clinic in The Gambia, HIV-1 and HIV-2 prevalence trends among all new patients being tested for HIV were examined over a 16 year period (1988 till 2003). In newly diagnosed patients a baseline CD4 count was done.
An HIV test was done in 23 363 patients aged 15 years or older. The prevalence of HIV-1 was 4.2% in 1988-91 and rose to 17.5% in 2001-03 (P < 0.0001, chi(2)-test for trend). The prevalence of HIV-2 was 7.0% in 1988-91 and declined to 4.0% in 2001-03 (P < 0.0001). HIV-1 prevalence increased and HIV-2 prevalence decreased with time in logistic regression models adjusting for age, sex, and indication for test (P < 0.0001). Baseline CD4 counts were available for 65% of patients. The median CD4 count was 215 cells/mm3 [interquartile range (IQR) 72-424] for HIV-1, and 274 (IQR 100-549) for HIV-2 infected patients. There was no marked trend of rise or decline in baseline CD4 count in either HIV-1 or HIV-2 infected patients over the study period. Forty-five per cent of newly diagnosed HIV patients had a CD4 count <200 cells/mm3.
These data suggest that HIV-1 prevalence is rising in The Gambia, and that HIV-2 is declining. HIV patients in The Gambia present late and almost half of patients would qualify for anti-retroviral treatment at their first visit.
Human immunodeficiency virus 2 (HIV-2) infection is a zoonosis in which simian immunodeficiency virus from a West African monkey species; the sooty mangabey is thought to have entered the human population on at least eight separate occasions. This has given rise to eight distinct HIV-2 groups, of which only groups A and B have continued to spread among humans; the other clades appear only to have led to single-person infections. Viral control in HIV-2 infection is associated with several distinct features-a high-magnitude cellular immune response directed toward conserved Gag epitopes, an earlier-differentiated CD8 + T cell phenotype with increased polyfunctionality and exceptionally high functional avidity, supported by polyfunctional virus-specific CD4 + T cells, against a background of substantially less extensive immune activation than is seen in human immunodeficiency virus 1 (HIV-1) infection. Emerging as one of the most striking differences from HIV-1 infection is the slower evolution and a possible lower frequency of adaptive immune escape in asymptomatic HIV-2-infected individuals.
It is now thirty years since the discovery of AIDS but its origins continue to puzzle doctors and scientists. Inspired by his own experiences working as an infectious diseases physician in Africa, Jacques Pepin looks back to the early twentieth-century events in Africa that triggered the emergence of HIV/AIDS and traces its subsequent development into the most dramatic and destructive epidemic of modern times. He shows how the disease was first transmitted from chimpanzees to man and then how urbanization, prostitution, and large-scale colonial medical campaigns intended to eradicate tropical diseases combined to disastrous effect to fuel the spread of the virus from its origins in Léopoldville to the rest of Africa, the Caribbean and ultimately worldwide. This is an essential new perspective on HIV/AIDS and on the lessons that must be learnt if we are to avoid provoking another pandemic in the future.
Aim
To evaluate the contributions of the member health research centres of the INDEPTH Network which operate health and demographic surveillance system (HDSS) field sites to research efforts on the epidemiology and impacts of HIV/AIDS in low- and middle-income countries, via a review of peer-reviewed published papers on HIV/AIDS that use the HDSS framework.
Methods
Publication titles were sent to INDEPTH by member centres. These were uploaded onto the Zotero research tool from different databases (most from PubMed). We searched for publications using the keyword “HIV” and the publication date. The 540 relevant papers were all published in peer-reviewed English language journals between 1999 and 2012. 71 papers were finally selected which met the key criterion for inclusion: papers must deal with the spread and impact of HIV.
Results
The study found that alcohol consumption, socioeconomic status, educational attainment and age are factors that put certain groups at higher risk of HIV infection. The study found strong effects of AIDS on household dissolution. Women with HIV whose husbands were uninfected faced a higher risk of separation and divorce than women in uninfected households or in households where both female and male partners were infected. Elderly women also face social stigma and isolation as a result of either living with HIV/AIDS themselves or caring for an individual who has the virus as well as financial difficulties on household welfare. Children with mothers who are infected with HIV appear to face threats to survival even while the mother remains alive.
Conclusion
INDEPTH member centres have tracked the course of the HIV/AIDS epidemic in sub-Saharan Africa. They have analysed how the virus is transmitted, how and where it emerged, which groups are most affected, and how the virus impacts families, communities and economies. The robust and extensive data they have generated provide critical insights to policy-makers as the epidemic moves into its fourth decade.
Plasma HIV-2 viral load has been reported as predictive of AIDS in HIV-2 infected patient but the lack of sensitivity of the current HIV2 viral load assay is a limitation for the monitoring of the HIV-2-infected patients.
To validate a new quantification assay based on a synthetic HIV-2 RNA transcript and real-time PCR with primers and probes selected in the LTR region, together with high-performance reagents and a protective RNA carrier.
We quantified 23 HIV-2 group A and B supernatants and 58 plasma samples with our TAQMAN-PCR assay and compared the results to those of our previously published in a real time reference PCR performed onto Light Cycler technology, the LC-PCR with a detection of 2.0log10 copies/ml.
The performance of TAQMAN-PCR was significantly improved, yielding a detection limit of 17 RNA copies/ml. There was a major difference (1-5log10 copies/ml) between LC-PCR and TAQMAN-PCR values for HIV-2 group B supernatants. Twenty-six of 27 plasma samples with levels higher than 2.0log10 copies/ml in LC-PCR were positive by TAQMAN-PCR. Ten of the 31 plasma samples below the LC-PCR detection limit were quantifiable with the TAQMAN-PCR.
The new primers and probe in the LTR region can circumvent HIV-2 diversity, making our method suitable for use in HIV-2 group B-infected patients. Use of a high-performance RT enzyme and RNA carrier protection contributed to improving the detection limit. This study confirms that plasma viral load is lower than 17copies/ml in a large number of HIV-2-infected patients.
The goal of this study was to determine how HIV and AIDS risk was framed in newspaper coverage of older adults. A content analysis was performed on articles published from 1989 to 2005 in urban newspapers. The findings were then compared with relevant information on the actual risks facing older adults. The results indicate a discrepancy in coverage between articles, including sources in the affected group. Articles omitting the affected sources inaccurately framed risk, emphasizing salacious topics rather than more important concerns. These findings suggest available risk information regarding HIV and AIDS and older adults distorts risk information for a population already underserved by health educators, which could contribute to rising infection rates.
Objectives:
To compare the population dynamics of HIV-2 and HIV-1, and to characterize ongoing HIV-2 transmission in rural Guinea-Bissau.
Design:
Phylogenetic and phylodynamic analyses using HIV-2 gag and env, and HIV-1 env sequences, combined with epidemiological data from a community cohort.
Methods:
Samples were obtained from surveys in 1989-1991, 1996-1997, 2003 and 2006-2007. Phylogenies were reconstructed using sequences from 103 HIV-2-infected and 56 HIV-1-infected patients using Bayesian Evolutionary Analysis by Sampling Trees (BEAST), a relaxed molecular clock and a Bayesian skyline coalescent model.
Results:
Bayesian skyline plots showed a strong increase in the 1990s of the HIV-1 effective population size (Ne) in the same period that the Ne of HIV-2 came into a plateau phase. The population dynamics of both viruses were remarkably similar following initial introduction. Incident infections were found more often in HIV-2 transmission clusters, with 55-58% of all individuals contributing to ongoing transmission. Some phylogenetically linked sexual partners had discordant viral loads (undetectable vs. detectable), suggesting host factors dictate the risk of disease progression in HIV-2. Multiple HIV-2 introductions into the cohort are evident, but ongoing transmission has occurred predominantly within the community.
Conclusion:
Comparison of HIV-1 and HIV-2 phylodynamics in the same community suggests both viruses followed similar growth patterns following introduction, and is consistent with the hypothesis that HIV-1 may have played a role in the decline of HIV-2 via competitive exclusion. The source of ongoing HIV-2 transmission in the cohort appears to be new HIV-2 cases, rather than the pool of older infections established during the early growth of HIV-2.
Different studies have evidenced the relationship between host abundance and health status of wildlife populations. Diseases
that benefit from wildlife overabundance can affect not only the fitness and trophy quality of game species, but also public
health, livestock health, and the conservation of endangered species. This paper reviews a number of European examples to
highlight the relationship between overabundance and disease in game species, and discusses the possibilities of limiting
the associated risks. Management tools to estimate overabundance are needed for legislative purposes and for the monitoring
of wildlife populations, but artificial feeding interferes in the objective measurement of overabundance. Therefore, we propose
a multidisciplinary approach to diagnose if a given wildlife population is overabundant. This includes not only signs such
as adverse effects on the soil, vegetation or fauna (first group), poor body condition scores, low trophy scores or low reproductive
performance (second group), or increased parasite burdens (third group), but also the measurement of infectious disease prevalences
(the fourth group of overabundance signs). This combined assessment of overabundance ideally requires the cooperation of wildlife
managers, botanists, and veterinarians. Once a given wildlife population is defined as overabundant, it is difficult to establish
palliative management actions. These can consist in banning certain management tools (e.g. feeding) or increasing the hunting
harvest, but both of them are difficult to implement in practice. A close monitoring of both wildlife densities and wildlife
diseases, the establishment of reference values for all signs of overabundance, and the mapping of the disease and density
hotspots will be needed to design adequate risk-control measures for each particular situation.
HIV type 2 (HIV-2), a closely related retrovirus discovered a few years after HIV type 1, causes AIDS in only a minority of infected individuals. Determining why HIV-2 causes asymptomatic infection in most patients could further our understanding of HIV immunopathogenesis. Studies to date have suggested that both enhanced immune responses and lower viral replication could play a role. We summarize the important findings to date and highlight areas that warrant further exploration.
To investigate the association between the three human retroviruses, HIV-1, HIV-2 and HTLV-I.
Community-based follow-up studies of retrovirus infections in two cohorts.
A total of 2057 individuals aged 35 years and over were eligible for inclusion. Participants were interviewed and had a blood sample drawn. Samples were analysed for HIV-1, HIV-2 and HTLV infections. Uni- and multivariate analyses that included behavioural and socio-economic factors were performed using logistic regression and Poisson regression models.
A total of 1686 individuals participated with a blood sample in the HIV prevalence analyses and 1581 individuals participated in the HTLV-I prevalence analyses. The overall prevalence was 2.1% for HIV-1, 13.5% for HIV-2 and 7.1% for HTLV-I. Comparing the < 45 year age group with 45+ year age groups, the female : male (F : M) prevalence ratio increased with age for all three retroviruses. Dual infections were more common in women than in men. Assuming independent distribution of the viruses, the observed prevalence of dual infections in women was significantly higher than expected, while the prevalence was not increased in men. The prevalence of dual infections increased with age in women, the odds ratio (OR) being 3.4 [95% confidence interval (CI), 1.0-11.3] for any combination of dual infection, while the prevalence decreased with age in men (OR, 0.3; 95% CI, 0.1-2.0) (test of interaction, P = 0.033). Control for behavioural factors did not modify these patterns.
The pattern of increased prevalence among older women could have public health implications; women of older age groups should be regarded as a potential vulnerable group and included in HIV/AIDS prevention programmes.
In this study we date the introduction of HIV-2 into the human population and estimate the epidemic history of HIV-2 subtype A in Guinea-Bissau, the putative geographic origin of HIV-2. The evolutionary history of the simian immunodeficiency virussooty mangabey/HIV-2 lineage was reconstructed by using available database sequences with known sampling dates, and a timescale for this history was calculated by using maximum likelihood methods. The date of the most recent common ancestor of HIV-2 subtype A strains was estimated to be 1940 +/- 16 and that of B strains was estimated to be 1945 +/- 14. In addition we used coalescent theory to estimate the past population dynamics of HIV-2 subtype A in a rural population of Guinea-Bissau. Parametric and nonparametric estimates of the effective number of infections through time were obtained for an equal sample of gag, pol, and env sequences. Our estimates of the epidemic history of HIV-2 subtype A in Guinea-Bissau show a transition from constant size to rapid exponential growth around 1955-1970. Our analysis provides evidence for a zoonotic transfer of HIV-2 during the first half of the 20th century and an epidemic initiation in Guinea-Bissau that coincides with the independence war (1963-1974), suggesting that war-related changes in sociocultural patterns had a major impact on the HIV-2 epidemic.
The aim of the present study was to investigate the long-term incidence rate of Lyme borreliosis and, additionally, to determine whether a correlation exists between climatic factors and summer-season variations in the incidence of Lyme borreliosis. Climatic variability acts directly on tick population dynamics and indirectly on human exposure to Lyme borreliosis spirochetes. In this study, conducted in primary healthcare clinics in southeastern Sweden, electronic patient records from 1997-2003 were searched for those that fulfilled the criteria for erythema migrans. Using a multilevel Poisson regression model, the influence of various climatic factors on the summer-season variations in the incidence of erythema migrans were studied. The mean annual incidence rate was 464 cases of erythema migrans per 100,000 inhabitants. The incidence was significantly higher in women than in men, 505 and 423 cases per 100,000 inhabitants, respectively (p<0.001). The summer-season variations in the erythema migrans incidence rate correlated with the monthly mean summer temperatures (incidence rate ratio 1.12; p<0.001), the number of winter days with temperatures below 0 degrees C (incidence rate ratio 0.97; p<0.001), the monthly mean summer precipitation (incidence rate ratio 0.92; p<0.05), and the number of summer days with relative humidity above 86% (incidence rate ratio 1.04; p<0.05). In conclusion, Lyme borreliosis is highly endemic in southeastern Sweden. The climate in this area, which is favourable not only for human tick exposure but also for the abundance of host-seeking ticks, influences the summer-season variations in the incidence of Lyme borreliosis.
Objectives: To compare the basic immunological changes induced by HIV-1 and HIV-2 infection and to assess the immune status of subjects serologically reactive to both HIV-1 and HIV-2 (dually-reactive). Design: Immune parameters were studied cross-sectionally in women delivering in Abidjan, Cote d'Ivoire, West Africa, where HIV-1 and HIV-2 are endemic. In this area, a significant number of sera from infected individuals are reactive to both HIV-1 and HIV-2. Subjects and methods: Two hundred and twenty-eight women delivering in a major maternity clinic were screened for HIV-1 and HIV-2 using an enzyme-linked immunosorbent assay. Seropositivity was confirmed by Western blot. The immune parameters studied were CD4+ and CD8+ lymphocyte subsets, immunoglobulin (Ig) serum levels, neopterin and beta-2-microglobulin (beta-2M) serum levels. Results: Similar but less pronounced immune changes were present in HIV-2-reactive subjects compared with HIV-1- and dually-reactive subjects. The observed differences between the HIV-seropositive groups could not be explained by differences in age or disease stage but paralleled differences in the frequency of persistent generalized lymphadenopathy (PGL). The intermediate immune profile of HIV-2-reactives (between seronegatives and HIV-1- and dually-reactives) was most clearly reflected by the number of CD8 + lymphocytes, the CD4 : CD8 ratio and the IgG serum level. Median neopterin and beta-2M levels, though significantly increased in all HIV-seropositive groups, did not differ significantly between HIV-2-, HIV-1- and dually-reactives. Conclusions: HIV-2 infection is associated with typical HIV-related immunological changes. Immunologically, dually-reactives resemble HIV-1-reactives more closely than HIV-2-reactive subjects.
A serosurvey was carried out to assess the prevalence of HIV infection in The Gambia and the importance of possible risk factors. The overall prevalence of HIV-2 infection among the 4228 adults studied was 1.7% while that of HIV-1 was 0.1%. The prevalence of HIV-2 was similar in both sexes but higher among those > 25 years of age and those who lived in two small towns along a main transport route. Among men, multivariate analysis showed prevalence of HIV-2 infection was significantly greater among those in the more affluent occupations, those without a secondary education and those with a history of urethral discharge. Among women, infection was more frequent in divorcees and widows and those who had been married several times. The prevalence was also higher in individuals born in Guinea-Bissau and in an ethnic group which originated there.
To compare the basic immunological changes induced by HIV-1 and HIV-2 infection and to assess the immune status of subjects serologically reactive to both HIV-1 and HIV-2 (dually-reactive).
Immune parameters were studied cross-sectionally in women delivering in Abidjan, Côte d'Ivoire, West Africa, where HIV-1 and HIV-2 are endemic. In this area, a significant number of sera from infected individuals are reactive to both HIV-1 and HIV-2.
Two hundred and twenty-eight women delivering in a major maternity clinic were screened for HIV-1 and HIV-2 using an enzyme-linked immunosorbent assay. Seropositivity was confirmed by Western blot. The immune parameters studied were CD4+ and CD8+ lymphocyte subsets, immunoglobulin (Ig) serum levels, neopterin and beta 2-microglobulin (beta 2M) serum levels.
Similar but less pronounced immune changes were present in HIV-2-reactive subjects compared with HIV-1- and dually-reactive subjects. The observed differences between the HIV-seropositive groups could not be explained by differences in age or disease stage but paralleled differences in the frequency of persistent generalized lymphadenopathy (PGL). The intermediate immune profile of HIV-2-reactives (between seronegatives and HIV-1- and dually-reactives) was most clearly reflected by the number of CD8+ lymphocytes, the CD4:CD8 ratio and the IgG serum level. Median neopterin and beta 2M levels, though significantly increased in all HIV-seropositive groups, did not differ significantly between HIV-2-, HIV-1- and dually-reactives.
HIV-2 infection is associated with typical HIV-related immunological changes. Immunologically, dually-reactives resemble HIV-1-reactives more closely than HIV-2-reactive subjects.
Between 1986 and 1989 health workers collected 3072 serum samples from 3 rural regions of Senegal (Casamance Kedougou and Fleuve) to test for HIV-1 and HIV-2 seropositivity. 43.3% of the samples were from school children and non of them tested positive for HIV-2 but none were for HIV-1 and HIV-2 prevalence was not uniform throughout the country. No one in the Fleuve region tested positive but 0.95% did in Casamance and 0.3% did in Kedougou. Yet 4% of migrant male workers from other regions of Senegal on a cotton plantation in Kedougou tested positive for HIV-2. These results indicated the need to further examine HIV prevalence in Casamance since it had the highest prevalence rate. In 1990 in Casamance health workers collected sera from 3239 adults. Overall HIV prevalence was 0.8% (27 people). 25 were HIV-2 seropositive and 2 were HIV-1 seropositive. 1 of the HIV-1 seropositive individuals had just come back from the Ivory Coast and the other had recently lived elsewhere. Median age for HIV infected persons was 39 years. HIV-infected men were more likely to be young (24-39 years old) than were the women (73% vs. 25%; p=.034). HIV prevalence was highest among 25-30 year old men (2.6%) and among 45-50 year old women (2%). Most of the 27 HIV seropositive people 12 were married 12 were single 2 women were divorced and 1 women was a widow. Even though HIV-1 and HIV-2 prevalence rates were low specific counseling HIV campaigns are needed to curb transmission.
The authors studied the prevalence and risk determinants for human immunodeficiency virus type 1 (HIV-1) and type 2 (HIV-2) in female prostitutes from Dakar (1985-1990), Ziguinchor (1987-1990), and Kaolack (1987-1990), Senegal, West Africa. Each cohort showed a distinct distribution of HIVs: 10.0% HIV-2 and 4.1% HIV-1 in Dakar, 38.1% HIV-2 and 0.4% HIV-1 in Ziguinchor, and 27.4% HIV-2 and 1.3% HIV-1 in Kaolack. In 1,275 female prostitutes from Dakar, increase years of sexual activity and a history of scarification were associated with HIV-2 seropositivity. In contrast, HIV-1 seroprevalence was associated with a shorter duration of prostitution and a history of hospitalization. In 278 female prostitutes from Ziguinchor, HIV-2 seroprevalence was associated with women of Guinea-Bissau nationality and increased years of sexual activity. In 157 female prostitutes from Kaolack, HIV-2 seroprevalence was associated with increased years of sexual activity and a history of never using condoms. The authors also studied the risk determinants for HIV-2 in the 1,280 Senegalese prostitutes pooled from all three sites. Controlling for ethnic group, women from Ziguinchor and Kaolack were more likely to be HIV-2 seropositive as compared with women from the Dakar site. Increased years of sexual activity were associated with HIV-2 seropositivity, while a history of excision and BCG vaccinations decreased the risk of HIV-2 infection.
Twenty-nine human immunodeficiency virus type 2 (HIV-2) seropositive women identified in a cross-sectional study in Bissau in 1987 participated in a follow-up study in 1988, where each was matched for age and marital status with two HIV-2 seronegative women. Detailed information about all pregnancies was obtained. The HIV-2 seropositive women and their controls had similar mean numbers of pregnancies, live children, children who died, and abortions. The HIV-2 seropositive women did not have a greater risk of having had an abortion or a child who died than did the HIV-2 seronegative women. No difference in survival was seen between children born to HIV-2 seropositive and HIV-2 seronegative women. The H/S-ratios and CD4 numbers were lower in the seropositive group, but none had values lower than 0.4 and 0.4 x 10(9)/L, respectively. Seven prospectively observed children born to HIV-2 seropositive mothers showed no sign of infection. The lack of evidence of transmission of HIV-2 from mother to child is suggested to be due to the absence of marked immunodeficiency in this random sample of the general population.
To define the epidemiology of HIV-2 infection, we conducted a case-control study among hospitalized patients at an acute care hospital in Bissau, Guinea-Bissau, a country with endemic HIV-2 infection. Among 128 patients with various diagnoses, 23 (18%) were positive for HIV-2 by ELISA and Western blot. One of these patients was serologically reactive for HIV-1 also, but PCR and viral culture revealed the presence of HIV-2 only. To study risk factors, behaviors, and AIDS knowledge related to the acquisition of HIV infection, 22 HIV-2-seropositive and 21 seronegative hospitalized patients were given a physical examination and administered a questionnaire. Among women, transfusion was associated with HIV-2 infection (OR = 14.4, p = 0.02); among men, sex with a prostitute was the principal risk factor (OR = undefined, p = 0.02). Although 79% of HIV-infected patients and controls had heard of AIDS, only 17% of all study participants and 50% of males reporting sex with prostitutes had used condoms in the previous year. These data suggest that the risk factors for HIV-2 infection are similar to those for HIV-1 and support previous studies showing that HIV-2 is the predominant HIV in Guinea-Bissau. Efforts to decrease transmission of HIV-2 should include screening for HIV-2 in blood for transfusion in endemic areas (now done in Bissau) and education about the risk of sexual transmission.
A serosurvey was carried out to assess the prevalence of HIV infection in The Gambia and the importance of possible risk factors. The overall prevalence of HIV-2 infection among the 4228 adults studied was 1.7% while that of HIV-1 was 0.1%. The prevalence of HIV-2 was similar in both sexes but higher among those greater than 25 years of age and those who lived in two small towns along a main transport route. Among men, multivariate analysis showed prevalence of HIV-2 infection was significantly greater among those in the more affluent occupations, those without a secondary education and those with a history of urethral discharge. Among women, infection was more frequent in divorcees and widows and those who had been married several times. The prevalence was also higher in individuals born in Guinea-Bissau and in an ethnic group which originated there.
PIP
Researchers took blood samples from 4228 adults aged 15 years in The Gambia to determine the prevalence of HIV-2 infection and risk factors. HIV-2 infection was more prevalent than HIV-1 infection. HIV-2 prevalence stood at 39% for females and 31% for males, but the difference was insignificant. Individuals 25 years old were more likely to be HIV-2 seropositive than those 25 (p.01). Further, HIV-2 prevalence was significantly higher in the small towns of Soma and Farafenni on the Trans-Gambia Highway than other areas of the country (p.01; 3.2% vs. 1.3% for Greater Banjul and 1.4% for the remainder of the country). It also was greater for people who had their blood samples taken at a health center than those who gave theirs elsewhere (p.01). HIV-2 infection was more prevalent for people born in Guinea- Bissau and in the Manjago tribe which originated from Guinea-Bissau than those born in The Gambia or elsewhere (p.025 for place of birth and p.01 for tribe). Marital status played an insignificant role in seropositivity for men, but divorced and widowed women had a significantly greater infection rate than other women (p.001; odds ratio [OR] 10.4 vs. 1-20). Further, infection significantly increased as the number of husbands women had had increased (p.05; OR 6.8). HIV- 2 positivity was significantly higher among women who reported using a condom at least once during the past year with casual partners (p.01; OR 16.7). Skilled manual laborers, businessmen, and traders were more likely to be infected with HIV-2 than farmers, unskilled laborers, and while collar men (p.05). Men with at least a secondary education were at significantly lower risk than men with less than a secondary education (p.01; OR .1 VS. .7-1.6). Men who had had at least 2 cases of urethral discharge had a significantly higher infection rate than those who did not (p.005; OR 4.8 vs. .8-1).
In a community based prevalence study of HIV infection in Bissau, West Africa, 1987, the population in 100 randomly selected "houses" was asked to participate. 89% (1329/1499) were examined and had a blood sample taken. None was HIV-1 seropositive but 4.7% were seropositive for HIV-2 (0.6% in children, 8.9% in those aged 15 years and over, and 20% in those aged 40 years and over). There was no significant difference in seroprevalence between areas or ethnic groups or between individuals of different civil status when age was taken into account. Sexual contact and blood transfusions were the dominant transmission routes, and no case of vertical transmission was identified. The HIV-2 seroprevalence in spouses of HIV-2 seropositive index persons was 40%. For a history of blood transfusion the relative risk of being HIV-2 seropositive was 103.6 in children and 2.4 for adults. After exclusion of spouses, no clustering of HIV-2 seropositivity was seen. At follow-up, after a mean observation time of 325 days, there was an excess mortality for HIV-2 seropositives. The relative risk of dying for HIV-2 seropositive children was 60.8 and for adults 5.0.
Serological evidence is presented here suggesting that a virus closely related to simian T-lymphotropic virus type III (STLV-III) infects man in Senegal, west Africa, a region where AIDS or AIDS-related diseases have not yet been observed. 25 sera from Senegalese individuals that were positive for antibodies to HTLV-III by enzyme-linked immunosorbent assay were examined for antibodies to HTLV-III and STLV-III by western blotting. Sera from individuals originating from regions where AIDS has been reported, such as the United States and Burundi (central Africa), reacted best with antigens of HTLV-III, although antibodies that cross-reacted with STLV-III p24 were also detected. Conversely, sera originating from Senegalese people reacted better with STLV-III than with HTLV-III. This was exemplified by the absence of reactivity in sera from both monkeys and Senegalese people to p41, an antigen regularly detected by sera from antibody positive individuals originating from central Africa or from the United States. In contrast sera from central Africa or the United States did not react with p32, the putative envelope transmembrane protein of STLV-III that is regularly detected by sera from both monkeys and antibody-positive Senegalese people. These results suggest that certain healthy Senegalese people have been exposed to a virus that is more closely related to STLV-III than to HTLV-III. The existence and study of such virus variants potentially with differential pathogenicity may provide important information for the development of an AIDS virus vaccine.
During a 6-month period in 1987, we examined patients clinically suspected of the acquired immune deficiency syndrome (AIDS) at the national hospital in Bissau, the capital of Guinea-Bissau, and found 20 cases that fulfilled the criteria for AIDS. The two most prevalent major symptoms were weight loss and diarrhea, and the most common minor symptoms generalized lymphadenopathy and generalized dermatitis. Six of 20 patients died within a couple of months. Nineteen of 20 patients were tested for human immunodeficiency virus type 1 (HIV-1) and type 2 (HIV-2) antibodies and were shown to be HIV-2 seropositive. During the same time period, a seroprevalence study of HIV-2 and HIV-1 was carried out, including 2,122 patients or healthy persons in Bissau. Antibodies to HIV-2 were demonstrated by enzyme-linked immunosorbent assay and verified by Western blot analysis in 8.6% (46/535) of prenatal women, in 7.9% (9/114) of women attending a family-planning clinic, in 4.4% (19/427) of applicants for scholarships, in 17.6% (16/91) of blood donors tested during the first 2 months and 5.3% (10/189) of blood donors tested during the following months, in 5.7% (2/35) of police officers, in 36.7% (11/30) of female prostitutes, in 15.8% (97/614) of outpatients suspected of having tuberculosis, and in 55.2% (48/87) of patients clinically suspected of AIDS or AIDS-related disease. One of 2,001 subjects tested had antibodies specific for HIV-1. Another subject had an antibody pattern compatible with both HIV-1 and HIV-2 infections.(ABSTRACT TRUNCATED AT 250 WORDS)
We recently reported the isolation of a new retrovirus, termed human immunodeficiency virus type 2 (HIV-2), from two West African patients with the acquired immunodeficiency syndrome (AIDS). This virus is related to but distinct from the well-characterized AIDS retrovirus, human immunodeficiency virus type 1 (HIV-1). We report here evidence of infection with HIV-2 in 30 patients, almost all from West Africa. Seventeen of them had a clinical syndrome indistinguishable from AIDS (7 of these 17 died). Others had either the AIDS-related complex or no HIV-related symptoms. All patients had serum antibodies reacting with HIV-2 in an indirect immunofluorescence assay. All serum tested contained antibodies reacting with the envelope glycoprotein of the virus in an immunoprecipitation assay. Cross-reactivity of serum antibodies with HIV-1 was detected in a minority of patients and varied according to the assay used. Retroviral isolates were obtained from the blood lymphocytes of 11 patients and were all identified as HIV-2 by nucleic acid hybridization; none hybridized with an HIV-1 probe. These findings indicate that some cases of AIDS in West Africa may be caused by HIV-2, but the extent of the spread of this virus and its clinical correlates will require careful epidemiologic investigation.
For our studies we used a HIV-2 specific Enzyme-Linked Immunosorbent Assay (ELISA) developed by Diagnostic Pasteur (Paris, France). No positive reactions were observed in any control sera. 16 (3.3%) out of 477 sera from African natives or people having had close contact with Africa were clearly positive in ELISA. This positivity was confirmed by specific indirect immunofluorescence assay and, in some cases, by radioimmunoprecipitation assay. 6 positive sera were from women and 10 from men. 9 were from natives and 7 belonged to the close contact category. Cross-reactivity of serum antibodies with HIV-1 was detected in only 2 out of the 16 positive cases by specific ELISA test. It is important to point out that 1 of the HIV-2 positive sera came from a native of Mozambique and 3 from people having previously inhibited in Angola. Therefore, infection with HIV-2 seems to have spread to other former Portuguese colonies and associated populations. Further and extensive studies need to be done to ascertain the HIV-2 epidemiological status of larger population groups. They should include foreign army soldiers which are, or were at one time, residents of Angola and Mozambique; these would possibly constitute a risk group capable of spreading HIV-2 infection in other countries.
Because of the similar virological properties of HIV types 1 and 2, HIV-2 was assumed to be as infectious and capable of inducing AIDS as HIV-1. Seroepidemiological studies have shown significant rates of HIV-2 infection in West Africa, and surveys from other regions of the world indicate that the spread of HIV-2 infection continues. However the pathogenic potential of HIV-2 is considered to be lower than that of HIV-1. It is therefore important to understand the transmission properties of HIV-2 and its contribution to the AIDS pandemic. Since 1985, we have prospectively studied 1452 registered female prostitutes in Dakar, Senegal, with sequential evaluation of their antibody status to HIV-1 and HIV-2. During the study the overall incidence of HIV-1 and HIV-2 was the same (1.11 per 100 person-years of observation [pyo]). However, the annual incidence of HIV-1 increased substantially: there was a 1.4-fold increased risk per year and thus a 12-fold increase in risk over the entire study period. The incidence of HIV-2 remained stable, despite higher HIV-2 prevalence. In our population the heterosexual spread of HIV-2 is significantly slower than that of HIV-1, which strongly suggests differences in the viruses' infectivity potential.
To investigate the clinical and immunologic effects, and pattern of mortality associated with HIV-2 infection.
A rural community in Guinea-Bissau.
Serologic screening of 2774 subjects aged > 14 years followed by studies of the prevalence of clinical and immunologic abnormalities among 133 subjects with HIV-2 infection and 160 seronegative controls, and surveillance of mortality among all subjects who were screened during a mean of 2 years of follow-up.
Generalized lymphadenopathy was the only clinical abnormality significantly associated with HIV-2 infection. Infection was associated with lower CD4 counts and higher beta 2-microglobulin and neopterin levels. During follow-up, 5.5% of infected subjects died compared with 1.8% of the seronegatives (rate ratio adjusted for age and sex, 3.5; 95% confidence interval ((CI), 1.8-6.7). Proportional hazard regression analysis showed that the rate ratio varied with age (P = 0.003) and there was some evidence that the excess of mortality in infected subjects was, in absolute terms, least in the oldest subjects (trend test; P = 0.08).
The findings support previous suggestions that HIV-2 is less pathogenic than HIV-1; the data also suggest that mortality associated with infection may be lower in older subjects.
To review the clinical, epidemiologic, and biological features of infection with the human immunodeficiency virus type 2 (HIV-2).
Studies published since 1981 identified from MEDLINE searches, articles accumulated by the author, bibliographies of identified articles, and discussions with other investigators.
Information for review was taken from the author's own studies, data from other investigators that have been submitted for publication, and from 131 of the more than 200 articles examined.
Pertinent studies were selected and the data synthesized into a review format.
Infection with HIV-2 is prevalent in West Africa and is increasingly being identified elsewhere. The human immunodeficiency virus type 2 is spread through sexual contact and via contaminated blood but, unlike HIV-1, perinatal transmission is limited. Human immunodeficiency virus type 2 is genetically much more closely related to the simian immunodeficiency virus (SIV) than to HIV-1; biological and demographic data suggest that HIV-2 may have originally been transmitted from monkeys to man. Although HIV-2 causes the acquired immunodeficiency syndrome (AIDS), the asymptomatic incubation period after infection with HIV-2 appears to be substantially longer than that following HIV-1 infection. Consistent with these clinical observations, genetic regulation of HIV-2 differs from that of HIV-1. Therapeutic studies of patients infected with HIV-2 are lacking.
The human immunodeficiency virus type 2 is prevalent in West Africa and is now recognized on several other continents, including North America. Its epidemiology, biology, and clinical course differ from HIV-1. Therapeutic studies are needed.
To determine the prevalence of HIV infection and its relationship to age, sex and other factors.
Cross-sectional survey of a rural community in Guinea-Bissau.
Questionnaire-administration and screening of sera from subjects aged > or = 15 years.
Of the 2770 subjects tested, 220 (7.9%) were HIV-2-seropositive, four (0.1%) were HIV-1-seropositive and 10 (0.4%) were dually reactive. Overall prevalence of HIV-2 was 9.3% in women, peaking at 17.2% in the 35-44 age group, and 6.6% in men, peaking at 19.1% in the 45-54 age group. The mean age of the four subjects with HIV-1 infection was 24 years, which was significantly lower than those with HIV-2 infection. HIV-2 infection was more prevalent among women who were widowed or divorced, women whose husbands were living away from the study area, and women who had lived in the capital, Bissau. The majority of subjects with an infected spouse remained uninfected and none of the women aged < 25 years whose husbands were infected were seropositive. The prevalence varied significantly between settlements within the study area.
The pattern of HIV-2 infection in this rural community has similarities to that found in urban Bissau, and prevalence in both areas peaks in older subjects than in HIV-1 foci. The findings support previous suggestions that HIV-2 is not a recent introduction to Guinea-Bissau, and that it is less pathogenic and less readily transmitted than HIV-1.
Community studies with 1-3 years of follow-up have reported four to five times higher mortality in HIV-2-infected than in uninfected adults. In a cohort study of HIV-1, an increasing difference in mortality rates of HIV-1-infected and uninfected individuals is expected over time, because of rising mortality with advancing HIV-1 infection. We therefore investigated long-term survival of HIV-2-infected adults.
Adults enrolled in 1987 in a community study of HIV-2 infection in Guinea-Bissau were followed up with serological surveys in 1989 and 1992. Survival was assessed in 1995, 9 years after enrollment.
The annual incidence of HIV-2 was 0.7% for adults and tended to be higher for older individuals than for participants aged 15-44 years (relative risk 3.21 [95% CI 0.91-11.37]). With control for age, HIV-2-infected adults had twice as high mortality as uninfected individuals (mortality ratio 2.32 [1.18-4.57]); the mortality ratio was highest in the first year of the study (4.50 [1.31-15.43]). The difference between infected and uninfected individuals was stronger for adults under 45 years of age (mortality ratio 4.72 [1.86-11.97]) than for older people (1.35 [0.51-3.56]). HIV-2-infected individuals living with an infected spouse had significantly higher mortality than HIV-2-infected individuals living with an uninfected spouse (p = 0.027).
HIV-2-associated mortality is not increasing with length of follow-up. Mortality in HIV-2-infected adults is only twice as high as that in uninfected individuals. In the majority of adults, HIV-2 has no effect on survival.
Data from an MRC case-control study in rural Guinea Bissau suggest older HIV-2 carriers (aged 55 to 80 years) appear, over a period of 2 years, to have a mortality similar to that of uninfected controls, whereas in HIV-2 carriers under the age of 55 there is a significantly higher mortality, compared with uninfected controls. Genotyping of viruses from both groups revealed only subtype a to be circulating. Thus, although putative nonpathogenic HIV-2 subtypes have been described in patients from West Africa, these do not appear to be contributing significantly to the nonpathogenic clinical phenotype in this population.
Prevalence and risk determinants of Human Immunodeficiency Virus Type 2 (HIV-2) and Human Immunodeficiency Virus Type 1 (HIV-1) in West African Female Prostitutes
- P Kanki
- M Boup
- S Marlink
incidence, prevalences and routes of transmission
- A G Poulsen
- P Aaby
- A Gottschau
The effects of HIV-2 infection in a rural area of Guinea-Bissau
- D Ricard
- A Wilkins
- N Gum
Sexually transmitted diseases and HIV-2 associated AIDS and HIV-2 seroprevalence in
- A Nauclér
- P Albino
- A P Da Silva
Nine years HIV-2 associated mortality in a community study from Guinea-Bissau
- A G Poulsen
- P Aaby
- H Jensen
Sexual behaviour and networking: anthropological and socio-cultural studies on the transmission of HIV. Liege: Ordina; 1992
- M Høgsborg
- P Aaby
Comparison of CD4 counts, viral load and genetic variation in HIV-2 infection: AIDS cases, old non-progressors and young asymptomatic subjects in Bissau
- H Norrgren
- M Silvia
- T Leithner