Risk factors for HIV-2 seropositivity among older people in Guinea-Bissau. A search for the early history of HIV-2 infection

HIV treatment in Guinea-Bissau: room for improvement and time for new treatment options

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.

HIV-2 continues to decrease, whereas HIV-1 is stabilizing in Guinea-Bissau

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% confidence interval (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.

Does smallpox vaccination modify HIV disease progression among ART-naive people living with HIV in Africa?

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 (β2m). 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 β2m level was 2·59 mg/l (IQR = 2·06-3·86). After adjustment, the presence of smallpox vaccine scar was not associated with a β2m 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 β2m 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.

Male Circumcision and the Epidemic Emergence of HIV-2 in West Africa

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.

Clinical presentation and opportunistic infections in HIV-1, HIV-2 and HIV-1/2 dual seropositive patients in Guinea-Bissau

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.

Differential effects of sex in a West African cohort of HIV-1, HIV-2 and HIV-1/2 dually infected patients: men are worse off

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 HIV-1/2 dually infected patients.

METHODS

This study utilised a retrospective cohort of treatment-naïve adults at the largest HIV clinic in Guinea-Bissau from 6 June 2005 to 1 December 2013. Baseline characteristics were assessed and the patients followed until death, transfer, loss to follow-up, or 1 June 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 5694 patients were included in the study, 3702 women (65%) and 1992 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 socio-economic status, have higher mortality and loss to follow-up than women.

Predicting the extinction of HIV-2 in rural Guinea-Bissau

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.

Profile of the HIV epidemic in Cape Verde: molecular epidemiology and drug resistance mutations among HIV-1 and HIV-2 infected patients from distinct islands of the archipelago

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.

HIV-2 Infection: Where Are We Today?

Context:

The choice of antiretroviral therapy for HIV-2 differs from that for HIV-1, underscoring the importance of differentiating between the two.

Aims:

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.

Setting and Design:

Retrospective analysis in a tertiary care teaching institute over a period of three years.

Materials and Methods:

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.

Statistical Analysis Used:

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.

Results:

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.

Conclusion:

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.

Highly sensitive plasma RNA quantification by real-time PCR in HIV-2 group A and group B infection

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.

OBJECTIVE

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.

STUDY DESIGN

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 2.0 log10 copies/ml.

RESULTS

The performance of TAQMAN-PCR was significantly improved, yielding a detection limit of 17 RNA copies/ml. There was a major difference (1-5 log10 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 2.0 log10 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.

CONCLUSIONS

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 17 copies/ml in a large number of HIV-2-infected patients.

Population dynamics of HIV-2 in rural West Africa: comparison with HIV-1 and ongoing transmission at the heart of the epidemic

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.

HTLV-1 in rural Guinea-Bissau: prevalence, incidence and a continued association with HIV between 1990 and 2007

Background

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.

Results

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).

Conclusions

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.

Dual infection with HIV-1 and HIV-2: double trouble or destructive interference?

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.

STD/AIDS prevention in Portuguese-speaking Africa: a review of the recent literature in the social sciences and health

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.

Prevalence and incidence of HIV-1 and HIV-2 before, during and after a civil war in an occupational cohort in Guinea-Bissau, West Africa

OBJECTIVES

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.

DESIGN

Open prospective cohort study of 4592 police officers in Guinea-Bissau, West Africa.

METHODS

Analysis of HIV-1 and HIV-2 prevalence and incidence divided in 2-3 years time strata.

RESULTS

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.

CONCLUSION

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.

HIV-2: the forgotten AIDS virus

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.

Behaviour change and competitive exclusion can explain the diverging HIV-1 and HIV-2 prevalence trends in Guinea-Bissau

The aim of this study was to determine whether a temporary rise in sexual risk behaviour during war in Guinea-Bissau could explain the observed trends in HIV-1 and HIV-2 prevalence, and to explore the possible contribution of competitive elimination of HIV-2 by HIV-1. A simulation model of the heterosexual transmission of sexually transmitted infections was parameterized using demographic, behavioural and epidemiological data from rural Guinea-Bissau, and fitted to the observed HIV-1 and HIV-2 trends with and without a historic rise in risk behaviour. The observed trends could only be simulated by assuming a temporary rise in risk behaviour. Around 30% of the projected decline in HIV-2 prevalence from a peak of 8.7% to 4.3% in 2010 was due to competitive elimination by HIV-1. Importantly for public health, HIV-1 prevalence was predicted to continue increasing and to become the dominant HIV type by 2010. Data collection is required to validate this prediction.

Mortality associated with HIV-1, HIV-2, and HTLV-I single and dual infections in a middle-aged and older population in Guinea-Bissau

BACKGROUND

In Guinea-Bissau HIV-1, HIV-2, and HTLV-I are prevalent in the general population. The natural history of HIV/HTLV-I single and dual infections has not been fully elucidated in this population. Previous studies have shown that combinations of these infections are more common in older women than in men. The present study compares mortality associated with HIV-1, HIV-2, and HTLV-I single and dual infections in individuals over 35 years of age within an urban community-based cohort in Guinea-Bissau.

RESULTS

A total of 2,839 and 1,075 individuals were included in the HIV and HTLV-I mortality analyses respectively. Compared with HIV-negative individuals, adjusted mortality rate ratios (MRRs) were 4.9 (95% confidence interval (CI): 2.3, 10.4) for HIV-1, 1.8 (95%CI: 1.5, 2.3) for HIV-2, and 5.9 (2.4, 14.3) for HIV-1/HIV-2 dual infections. MRR for HTLV-I-positive compared with HTLV-I-negative individuals was 1.7 (1.1, 2.7). Excluding all HIV-positive individuals from the analysis, the HTLV-I MRR was 2.3 (1.3, 3.8). The MRR of HTLV-I/HIV-2 dually infected individuals was 1.7 (0.7, 4.3), compared with HIV/HTLV-I-negative individuals. No statistically significant differences were found in retrovirus-associated mortality between men and women.

CONCLUSION

HIV-1-associated excess mortality was low compared with community studies from other parts of Africa, presumably because this population was older and the introduction of HIV-1 into the community recent. HIV-2 and HTLV-I-associated mortality was 2-fold higher than the mortality in uninfected individuals. We found no significant differences between the mortality risk for HIV-2 and HTLV-I single infection, respectively, and HIV-2/HTLV-I dual infection. The higher prevalence of retroviral dual infections in older women is not explained by differential retrovirus-associated mortality for men and women.

Trends of HIV-1 and HIV-2 prevalence among pregnant women in Guinea-Bissau, West Africa: possible effect of the civil war 1998 1999

OBJECTIVES

Sentinel surveys in Bissau, the capital of Guinea-Bissau, have shown low prevalence of HIV-1 but high HIV-2 prevalence before 1998. Guinea-Bissau experienced a civil war in 1998-1999. To examine specifically the trends of HIV prevalence from antenatal surveys in Bissau, Guinea-Bissau in 1987-2004, and whether the civil war in 1998-1999 could have an effect on HIV prevalence levels after the conflict.

METHODS

Since 1987, anonymous HIV testing in delivering women has been performed at the maternity clinic, Simão Mendes National Hospital, Bissau, as part of the national sentinel surveillance programme. Consecutive sampling was performed for approximately 3 months between September and December each year. Serological analyses were performed at the National Public Health Laboratory in Guinea-Bissau.

RESULTS

A total of 20 422 women were tested for HIV between 1987 and 2004. The total HIV-1 prevalence increased from 0.0% in 1987 to 4.8% in 2004 and the total HIV-2 prevalence decreased from 8.3% in 1987 to 2.5% in 2004. The HIV-1 prevalence increased from 2.5% in 1997 to 5.2% in 1999, but stabilized in subsequent years.

CONCLUSIONS

There was a significant increase in HIV-1 prevalence in the years 1987-2004 and a significant decline in HIV-2 prevalence over the same period. The civil war in 1998-1999 may have sparked HIV-1 transmission, as HIV-1 prevalence more than doubled between 1997 and 1999, but there is no evidence of a long-term effect on the trends of HIV-1 or HIV-2 prevalence.

Prevalence of HIV infection in conflict-affected and displaced people in seven sub-Saharan African countries: a systematic review

BACKGROUND

Violence and rape are believed to fuel the HIV epidemic in countries affected by conflict. We compared HIV prevalence in populations directly affected by conflict with that in those not directly affected and in refugees versus the nearest surrounding host communities in sub-Saharan African countries.

METHODS

Seven countries affected by conflict (Democratic Republic of Congo, southern Sudan, Rwanda, Uganda, Sierra Leone, Somalia, and Burundi) were chosen since HIV prevalence surveys within the past 5 years had been done and data, including original antenatal-care sentinel surveillance data, were available. We did a systematic and comprehensive literature search using Medline and Embase. Only articles and reports that contained original data for prevalence of HIV infection were included. All survey reports were independently evaluated by two epidemiologists to assess internationally accepted guidelines for HIV sentinel surveillance and population-based surveys. Whenever possible, data from the nearest antenatal care and host country sentinel site of the neighbouring countries were presented. 95% CIs were provided when available.

FINDINGS

Of the 295 articles that met our search criteria, 88 had original prevalence data and 65 had data from the seven selected countries. Data from these countries did not show an increase in prevalence of HIV infection during periods of conflict, irrespective of prevalence when conflict began. Prevalence in urban areas affected by conflict decreased in Burundi, Rwanda, and Uganda at similar rates to urban areas unaffected by conflict in their respective countries. Prevalence in conflict-affected rural areas remained low and fairly stable in these countries. Of the 12 sets of refugee camps, nine had a lower prevalence of HIV infection, two a similar prevalence, and one a higher prevalence than their respective host communities. Despite wide-scale rape in many countries, there are no data to show that rape increased prevalence of HIV infection at the population level.

INTERPRETATION

We have shown that there is a need for mechanisms to provide time-sensitive information on the effect of conflict on incidence of HIV infection, since we found insufficient data to support the assertions that conflict, forced displacement, and wide-scale rape increase prevalence or that refugees spread HIV infection in host communities.

Vaccinia scars associated with improved survival among adults in rural Guinea-Bissau

BACKGROUND

In urban Guinea-Bissau, adults with a vaccinia scar had better survival but also a higher prevalence of HIV-2 infection. We therefore investigated the association between vaccinia scar and survival and HIV infection in a rural area of Guinea-Bissau.

METHODOLOGY/PRINCIPAL FINDINGS

In connection with a study of HIV in rural Guinea-Bissau, we assessed vaccinia and BCG scars in 193 HIV-1 or HIV-2 infected and 174 uninfected participants. Mortality was assessed after 2(1/2)-3 years of follow-up. The analyses were adjusted for age, sex, village, and HIV status. The prevalence of vaccinia scar was associated with age, village, and HIV-2 status but not with sex and schooling. Compared with individuals without any scar, individuals with a vaccinia scar had better survival (mortality rate ratio (MR) = 0.22 (95% CI 0.08-0.61)), the MR being 0.19 (95% CI 0.06-0.57) for women and 0.40 (95% CI 0.04-3.74) for men. Estimates were similar for HIV-2 infected and HIV-1 and HIV-2 uninfected individuals. The HIV-2 prevalence was higher among individuals with a vaccinia scar compared to individuals without a vaccinia scar (RR = 1.57 (95% CI 1.02-2.36)).

CONCLUSION

The present study supports the hypothesis that vaccinia vaccination may have a non-specific beneficial effect on adult survival.

Protective immunity against HIV infection: lessons from HIV-2 infection

Despite two decades of intensive research, the correlates of protective immunity to HIV-1 infection remain elusive. Much less attention has been paid to the related human virus strain, HIV-2, which can cause AIDS, but does not usually do so in the majority of infected people. What can be learned from HIV-2 infection about how the human host can peacefully coexist with a pathogenic retrovirus?

In vitro replication capacity of HIV-2 variants from long-term aviremic individuals

To establish whether efficient suppression of virus replication in HIV-2-infected individuals is associated with low replicative capacity of HIV-2, replication kinetics of HIV-2 variants from long-term aviremic individuals was analyzed and compared with that of the relatively slow-replicating HIV-1 variants from asymptomatics and long-term nonprogressors (AS/LTNP). On average, HIV-2 from aviremic individuals had lower replication rates than HIV-1 variants from AS/LTNP in cells of 8 donors (0.45 log10 [range 0.14-0.77] vs. 0.58 log10 [range 0.32-0.99] pg RT/ml/day, P = 0.036). The relatively low replication rate of HIV-2 compared to HIV-1 variants was not related to different sensitivities to inhibition by CD8+ T cells or different degrees of infectivity. HIV-2 replication rates increased with progressive infection and with switch from CCR5 to CXCR4 usage. The relatively low replicative capacity of HIV-2 variants from aviremic individuals likely contributes to the low viral load and benign course of infection in these individuals.

Parenteral transmission during excision and treatment of tuberculosis and trypanosomiasis may be responsible for the HIV-2 epidemic in Guinea-Bissau

BACKGROUND AND OBJECTIVE

The factors that led to the simultaneous emergence, decades ago, of HIV-1 in central Africa and HIV-2 in West Africa remain unclear. The low HIV-2-associated mortality enables epidemiological assessment of risk factors potentially relevant in the early stages of the epidemic. In Guinea-Bissau, its epicentre, HIV-2 became highly prevalent (approximately 15%) in cohorts of individuals born before 1962, but is now disappearing whereas HIV-1 prevalence is increasing. We sought to verify the hypothesis that parenteral transmission was the key factor in the building-up of the HIV-2 epidemic.

DESIGN

Cross-sectional community survey of 1608 individuals aged > or = 50 years in Bissau.

METHODS

Capillary blood was obtained for HIV serology. Associations between HIV-2 (alone or in dual HIV-1/HIV-2 infections) and exposures were measured with crude and adjusted odds ratios (AOR) and 95% confidence intervals (CI).

RESULTS

Prevalence of HIV-2 was higher in women (160/1063; 15.1%) than men (45/545; 8.3%, P < 0.001). Among women, excision (AOR, 1.54; 95% CI, 1.08-2.18) was independently associated with HIV-2, as were age and being widowed (AOR, 1.88; 95% CI, 1.29-2.74). Among men, HIV-2 was not associated with sexually transmitted infections or transactional sex. In an analysis comprising men and women that was adjusted for age, sex, ethnic group and marital status, HIV-2 was associated with having received injections for the treatment of tuberculosis (AOR, 2.12; 95% CI, 1.11-4.05) or trypanosomiasis (AOR, 1.75; 95% CI, 1.03-2.97).

CONCLUSIONS

Parenteral transmission through ritual excision and multiple injections during treatment of tuberculosis and trypanosomiasis contributed to the emergence of HIV-2 in Guinea-Bissau.

Sixteen years of HIV surveillance in a West African research clinic reveals divergent epidemic trends of HIV-1 and HIV-2

BACKGROUND

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

Simian immunodeficiency virus infection in free-ranging sooty mangabeys (Cercocebus atys atys) from the Taï Forest, Côte d'Ivoire: implications for the origin of epidemic human immunodeficiency virus type 2

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.

Impact of long-term civil disorders and wars on the trajectory of HIV epidemics in sub-Saharan Africa

From the mid-1970s, seven countries in sub-Saharan Africa have experienced civil disorders and wars lasting for at least 10 years. In two-- Sierra Leone during 1991-2002, and Somalia from 1988 and continuing--adult HIV prevalence remained below 1%. In the Democratic Republic of the Congo, HIV prevalence appears to have stabilised during post-1991 civil disorder and war. Limited information from Angola (civil war 1975 -2002) and Liberia (civil disorder and war from 1989 and continuing) suggests low HIV prevalence. Mozambique's HIV prevalence was near 1% after its 1975 - 1992 civil war, but increased dramatically in the first post-war decade. Across African countries with long-term wars, HIV seems to have spread more slowly than in most neighbouring countries at peace. This evidence contributes to the ongoing debate about the factors that explain differential epidemic trajectories, a debate which is crucial to the design of HIV prevention programmes. One possible explanation for slow epidemic growth in wartime is that unsterile health care accounts for an important proportion of HIV transmission during peacetime, but much less when wars disrupt health services. However, other explanations are also possible. The roles of sex and blood exposures in HIV epidemics in war and peace await empirical determination.

Mobility and the spread of human immunodeficiency virus into rural areas of West Africa

BACKGROUND

In eastern and southern Africa, the human immunodeficiency virus (HIV) epidemic appeared first in urban centres and then spread to rural areas. Its overall prevalence is lower in West Africa, with the highest levels still found in cities. Rural areas are also threatened, however, because of the population's high mobility. We conducted a study in three different communities with contrasting infection levels to understand the epidemiology of HIV infection in rural West Africa.

METHOD

A comparative cross-sectional study using a standardized questionnaire and biological tests was conducted among samples in two rural communities of Senegal (Niakhar and Bandafassi, 866 and 952 adults, respectively) and a rural community of Guinea-Bissau (Caio, 1416 adults). We compared the distribution of population characteristics and analysed risk factors for HIV infection in Caio at the individual level.

RESULTS

The level of HIV infection was very low in Niakhar (0.3%) and Bandafassi (0.0%), but 10.5% of the adults in Caio were infected, mostly with HIV type 2 (HIV-2). Mobility was very prevalent in all sites. Short-term mobility was found to be a risk factor for HIV infection among men in Caio (adjusted odds ratio (aOR) = 2.06; 95% CI: 1.06-3.99). Women from Caio who reported casual sex in a city during the past 12 months were much more likely to be infected with HIV (aOR = 5.61 95% CI: 1.56-20.15). Short-term mobility was associated with risk behaviours at all sites.

CONCLUSIONS

Mobility appears to be a key factor for HIV spread in rural areas of West Africa, because population movement enables the virus to disseminate and also because of the particularly risky behaviours of those who are mobile. More prevention efforts should be directed at migrants from rural areas who travel to cities with substantial levels of HIV infection.

Tracing the origin and history of the HIV-2 epidemic

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.

Dual infections with HIV-1, HIV-2 and HTLV-I are more common in older women than in men in Guinea-Bissau

OBJECTIVES

To investigate the association between the three human retroviruses, HIV-1, HIV-2 and HTLV-I.

DESIGN

Community-based follow-up studies of retrovirus infections in two cohorts.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.