Prevalence, genetic diversity and antiretroviral drugs resistance-associated mutations among untreated HIV-1-infected pregnant women in Gabon, central Africa

Current Resistance of HIV-1 Strains Isolated in Volunteer Blood Donors in Gabon

Detection of drug resistance mutations (DRMs) and HIV-1 subtypes ensures effective therapeutic management for HIV-infected individuals. In Gabon, data on DRMs are very little available in the population of people living with HIV and also among voluntary HIV-positive blood donors. This study aimed to study subtypes and DRMs in HIV-1-positive volunteer blood donors in Gabon. A cross-sectional study was carried out at the National Blood Transfusion Center of Gabon. A purposive sampling method was used to collect 128 HIV-1 seropositive blood samples. Viral RNA was extracted on real-time PCR (Abbott 2000®), and sequencing was performed on ABI 3500 (Hitachi®). SPSS version 21.0 software was used for statistical analysis. Of the 128 seropositive volunteer donors included, men and the 29-39-age group were more representative at 78.9% and 49.2%, respectively. Eighty-two samples were sequenced. The majority strains identified were subtype A, subtype F, subtype G, CRF02_AG, and CRF45_cpx. The resistance mutations identified were K103N, L210W, E138G, V179D, V179T, and M46L. The prevalence of resistant subtypes was 25.6%. CRF02_AG strains exhibited high-level resistance to non-nucleoside reverse transcriptase inhibitors (NNRTIs), including efavirenz and nevirapine. The study identified major DRMs in reverse transcriptase and protease that confer high-level resistance to most NNRTIs, nucleoside reverse transcriptase inhibitors, and protease inhibitors. CRF02_AG was more predominant, and the frequency of resistant subtypes was high. However, these data will contribute to the therapeutic choice during the initiation of antiretroviral treatment in treatment-naive patients in Gabon.

HIV protease resistance mutations in patients receiving second-line antiretroviral therapy in Libreville, Gabon

INTRODUCTION

In 2022, the WHO reported that 29.8 million people around the world were living with HIV (PLHIV) and receiving antiretroviral treatment (ART), including 25‌ 375 people in Gabon (54% of all those living with HIV in the country). The literature reports a frequency of therapeutic failure with first-line antiretrovirals (ARVs) of between 20% and 82%. Unfortunately, data relating to the failure of second-line ARVs are scarce in Gabon. This study aims to determine the profiles of HIV drug resistance mutations related to protease inhibitors in Gabon.

METHODOLOGY

Plasma from 84 PLHIV receiving ARVs was collected from 2019 to 2021, followed by RNA extraction, amplification, and sequencing of the protease gene. ARV resistance profiles were generated using the Stanford interpretation algorithm version 8.9-1 ( https://hivdb.stanford.edu ) and statistical analyses were performed using EpiInfo software version 7.2.1.0 (CDC, USA).

RESULTS

Of 84 HIV plasma samples collected from 45 men and 39 women, 342 mutations were detected. Of these, 43.3% (148/342) were associated with nucleoside reverse transcriptase inhibitors (NRTIs), 30.4% (104/342) with non-nucleoside reverse transcriptase inhibitors (NNRTIs), and 26.3% (90/342) with protease inhibitors (PIs). Most NRTI mutations were associated with thymidine analogues (TAMs) (50.7%; 75/148), including T215F/V (14.9%; 22/148), D67DN/E/G/N/T (10.1%; 15/148), M41L (9.5%; 14/148), and K70E/KN/S/R (9.5%; 14/148). Resistance mutations related to non-TAM NRTIs (33.1%; 49/148) were M184V (29.1%; 43/148), and L74I/V (8.1%; 12/148). NNRTI mutations were predominantly K103N/S (32.7%; 34/104), V108I (10.6%; 11/104), A98G (10.6%; 11/104), and P225H (9.6%; 10/104). Minor mutations associated with PIs (60.0%; 54/90) were predominantly K20I (15.6%; 14/90) and L10F/I/V (14.5%; 13/90). The major mutations associated with PIs (40.0%; 36/90) were M41L (12.2%; 11/90), I84V (6.7%; 06/90), and V82A (6.7%; 06/90). The four most prescribed therapeutic regimens were TDF + 3TC + LPV/r (20.3%; 17/84), ABC + DDI + LPV/r (17.9%; 15/84), TDF + FTC + LPV/r (11.9%; 10/84), and ABC + 3TC + LPV/r (11.9%; 10/84).

CONCLUSION

This study revealed that HIV drug resistance mutations are common in Gabon. The major mutations associated with PIs were M41L, I84V, and V82A. There is a need for access to new NRTIs, NNRTIs, and PIs for a better therapeutic management of PLHIV in Gabon.

Genetic diversity of the human immunodeficiency virus of type 1 in Gabonese transfusional settings

BACKGROUND

The high endemicity of transfusion-transmissible infections (TTIs) in sub-Saharan Africa is a real public health problem. To reduce the risk of HIV transmission through blood donation, the NBTC of Gabon has launched in recent years a reorganization of its blood transfusion system. This study aims to characterize the molecular strains of HIV-1 circulating in donors and to estimate the risk of viral transmission.

MATERIALS AND METHODS

A cross-sectional study was carried out during the period from August 2020 to August 2021 among 381 donors who had agreed to donate blood at the National Blood Transfusion Center (NBTC). Viral load was determined by Abbott Real-Time (Abbott m2000®, Abbott) and sequencing by the Sanger method (ABI 3500 Hitachi®). The phylogenetic tree was constructed by MEGA X software. Data were checked, entered, and analyzed using SPSS version 21.0 software, with p ≤ 0.05 considered statistically significant.

RESULTS

A total of 381 donors were enrolled in the study. Among the 359 seronegative donors, five (5) seronegative donors were detected positive for HIV-1 using Real-Time PCR. The residual risk was 648 per 1,000,000 donations. The prevalence of residual infection was 1.4% [0,01; 0,03]. Sixteen (16) samples were sequenced. The strains obtained were CRF02_AG (50%), subtype A1 (18.8%), subtype G (12.5%), CRF45_cpx (12.5%) and subtype F2 (6.2%). Six sequences clustered with A1, G, CRF02_AG, and CRF45_cpx subtypes.

CONCLUSION

The residual risk of HIV-1 transmission by blood transfusion remains a concern in the Gabonese transfusional settings. A policy based on improving the current screening strategy would involve the implementation of the nucleic acid test (NAT) in order to optimize the safety of the donation by detecting the HIV-1 subtypes in circulation in the donors.

Human T-Cell Leukemia Virus Type 1-Related Diseases May Constitute a Threat to the Elimination of Human Immunodeficiency Virus, by 2030, in Gabon, Central Africa

The Joint United Nations Program on HIV/AIDS (UNAIDS) has adopted the Sustainable Development Goals (SDGs) to end the HIV/AIDS epidemic by 2030. Several factors related to the non-suppression of HIV, including interruptions of antiretroviral therapy (ART) and opportunistic infections could affect and delay this projected epidemic goal. Human T-Cell leukemia virus type 1 (HTLV-1) appears to be consistently associated with a high risk of opportunistic infections, an early onset of HTLV-1 and its associated pathologies, as well as a fast progression to the AIDS phase in co-infected individuals, when compared to HIV-1 or HTLV-1 mono-infected individuals. In Gabon, the prevalence of these two retroviruses is very high and little is known about HTLV-1 and the associated pathologies, leaving most of them underdiagnosed. Hence, HTLV-1/HIV-1 co-infections could simultaneously imply a non-diagnosis of HIV-1 positive individuals having developed pathologies associated with HTLV-1, but also a high mortality rate among the co-infected individuals. All of these constitute potential obstacles to pursue targeted objectives. A systematic review was conducted to assess the negative impacts of HTLV-1/HIV-1 co-infections and related factors on the elimination of HIV/AIDS by 2030 in Gabon.

Evaluation of the safety and efficacy of dihydroartemisinin-piperaquine for intermittent preventive treatment of malaria in HIV-infected pregnant women: protocol of a multicentre, two-arm, randomised, placebo-controlled, superiority clinical trial (MAMAH project)

INTRODUCTION

Malaria infection during pregnancy is an important driver of maternal and neonatal health especially among HIV-infected women. Intermittent preventive treatment in pregnancy (IPTp) with sulphadoxine-pyrimethamine is recommended for malaria prevention in HIV-uninfected women, but it is contraindicated in those HIV-infected on cotrimoxazole prophylaxis (CTXp) due to potential adverse effects. Dihydroartemisinin-piperaquine (DHA-PPQ) has been shown to improve antimalarial protection, constituting a promising IPTp candidate. This trial's objective is to determine if monthly 3-day IPTp courses of DHA-PPQ added to daily CTXp are safe and superior to CTXp alone in decreasing the proportion of peripheral malaria parasitaemia at the end of pregnancy.

METHODS AND ANALYSIS

This is a multicentre, two-arm, placebo-controlled, individually randomised trial in HIV-infected pregnant women receiving CTXp and antiretroviral treatment. A total of 664 women will be enrolled at the first antenatal care clinic visit in sites from Gabon and Mozambique. Participants will receive an insecticide-treated net, and they will be administered monthly IPTp with DHA-PPQ or placebo (1:1 ratio) as directly observed therapy from the second trimester of pregnancy. Primary study outcome is the prevalence of maternal parasitaemia at delivery. Secondary outcomes include prevalence of malaria-related maternal and infant outcomes and proportion of adverse perinatal outcomes. Participants will be followed until 6 weeks after the end of pregnancy and their infants until 1 year of age to also evaluate the impact of DHA-PPQ on mother-to-child transmission of HIV. The analysis will be done in the intention to treat and according to protocol cohorts, adjusted by gravidity, country, seasonality and other variables associated with malaria.

ETHICS AND DISSEMINATION

The protocol was reviewed and approved by the institutional and national ethics committees of Gabon and Mozambique and the Hospital Clinic of Barcelona. Project results will be presented to all stakeholders and published in open-access journals.

TRIAL REGISTRATION NUMBER

NCT03671109.

Absence of Resistance Mutations in the Integrase Coding Region among ART-Experienced Patients in the Republic of the Congo

BACKGROUND

HIV infects around one hundred thousand patients in the Republic of the Congo. Approximately 25% of them receive an antiretroviral treatment; current first-line regimens include two NRTIs and one NNRTI, reverse transcriptase inhibitors. Recently, protease inhibitors (PIs) were also introduced as second-line therapy upon clinical signs of treatment failure. Due to the limited number of molecular characterizations and amount of drug resistance data available in the Republic of the Congo, this study aims to evaluate the prevalence of circulating resistance mutations within the pol region.

METHODS

HIV-positive, ART-experienced patients have been enrolled in four semi-urban localities in the Republic of the Congo. Plasma samples were collected, and viral RNA was extracted. The viral load for each patient was evaluated by RT-qPCR, following the general diagnostic procedures of the University Hospital of Bordeaux. Finally, drug resistance genotyping and phylogenetic analysis were conducted following Sanger sequencing of the pol region.

RESULTS

A high diversity of HIV-1 strains was observed with many recombinant forms. Drug resistance mutations in RT and PR genes were determined and correlated to HAART. Because integrase inhibitors are rarely included in treatments in the Republic of the Congo, the prevalence of integrase drug resistance mutations before treatment was also determined. Interestingly, very few mutations were observed.

CONCLUSIONS

We confirmed a high diversity of HIV-1 in the Republic of the Congo. Most patients presented an accumulation of mutations conferring resistance against NRTIs, NNRTIs and PIs. Nonetheless, the absence of integrase mutations associated with drug resistance suggests that the introduction of integrase inhibitors into therapy will be highly beneficial to patients in the Republic of the Congo.

Factors associated with adherence to ARV treatment in people living with HIV/AIDS in a rural area (Koula-Moutou) in East Gabon

The goal of this study was to evaluate the impact of socio-clinical factors on adherence to antiretroviral treatment in people living with HIV/AIDS in Koula-Moutou (a rural area of Gabon). Two adherence assessment methods based on patient declaration and compliance with pharmacy visits were used to determine qualitative and quantitative aspects of adherence to antiretroviral therapy (ART). The quantitative (82.2%) and qualitative (79.5%) adherences to ART declared by patients were higher than those obtained through pharmacy visit assessment methods (15.8% and 45.2%, respectively). Moreover, the declarative and pharmacy visit compliance methods showed fair agreement (quantitative Kappa = 0.317; qualitative Kappa = 0.311). A better quantitative or qualitative declarative adherence was associated with a lower level of education (P = 0.05 and P = 0.025 respectively). This study reported for the first time the factors influencing adherence to ART in a rural area of East Gabon. We recommend further investigations in a large cohort to better assess the impact of socio-clinical factors on ART adherence in a vulnerable group of patients.

Sero-prevalence and risk factors for hepatitis E virus infection among pregnant women in the Cape Coast Metropolis, Ghana

BACKGROUND

Hepatitis E virus is an emerging infection in Africa with poor maternal and foetal outcomes. There is scanty data on the sero-prevalence of HEV infection among pregnant women in Ghana. This study highlighted the prevalence and risk factors associated with HEV infection among pregnant women in Cape Coast Metropolis, Central Region of Ghana.

METHODS

A multicenter (3 selected sites) analytical cross sectional study involving 398 pregnant women in the Cape Coast metropolis was conducted. HEV (Anti-HEV IgG and Anti-HEV IgM) ELISA was performed. Sero-positive women had liver chemistries done and data collected on maternal and neonatal outcomes. Data analyses were performed using Stata version 13 software (STATA Corp, Texas USA).

RESULTS

Mean age was 28.01 (± 5.93) years. HEV sero-prevalence was 12.2% (n = 48) for IgG and 0.2% (n = 1) for IgM with overall of 12.3%. The odds of being HEV sero-positive for women aged 26-35 years was 3.1 (95% CI: 1.1-8.1), p = 0.02 and ≥36 years it was 10.7 (95% CI; 3.4-33.5), p = 0.0001. Living in urban settlement was associated with lowest odds of HEV infection {OR 0.4 (95% CI; 0.2-0.8), p = 0.01}. Factors with no statistical evidence of association include main source of drinking water and history of blood transfusion. The sero-prevalence of HEV IgG increased progressively across trimesters with the highest among women in their third trimester (55.3%). None of the 49 HEV sero-positive women had elevated ALT level. Ten (N = 41) of the neonates born to sero-positive women developed jaundice in the neonatal period. The mean birth weight was 3.1kg (SD 0.4).

CONCLUSION

HEV sero-prevalence among pregnant women in the Cape Coast Metropolis is high enough to deserve more attention than it has received so far. It is therefore important to conduct further research on the potential impact on maternal and neonatal mortality and morbidity in Ghana.

Unravelling the complicated evolutionary and dissemination history of HIV-1M subtype A lineages

Subtype A is one of the rare HIV-1 group M (HIV-1M) lineages that is both widely distributed throughout the world and persists at high frequencies in the Congo Basin (CB), the site where HIV-1M likely originated. This, together with its high degree of diversity suggests that subtype A is amongst the fittest HIV-1M lineages. Here we use a comprehensive set of published near full-length subtype A sequences and A-derived genome fragments from both circulating and unique recombinant forms (CRFs/URFs) to obtain some insights into how frequently these lineages have independently seeded HIV-1M sub-epidemics in different parts of the world. We do this by inferring when and where the major subtype A lineages and subtype A-derived CRFs originated. Following its origin in the CB during the 1940s, we track the diversification and recombination history of subtype A sequences before and during its dissemination throughout much of the world between the 1950s and 1970s. Collectively, the timings and numbers of detectable subtype A recombination and dissemination events, the present broad global distribution of the sub-epidemics that were seeded by these events, and the high prevalence of subtype A sequences within the regions where these sub-epidemics occurred, suggest that ancestral subtype A viruses (and particularly sub-subtype A1 ancestral viruses) may have been genetically predisposed to become major components of the present epidemic.

Importance of Madagascar's HIV/AIDS reference laboratory

OBJECTIVE

We aimed to describe the challenge faced by the national reference laboratory to support the national HIV/AIDS response in Madagascar.

METHODS

Collaboration between the National Reference Laboratory of Madagascar (NRLM) and foreign partners (a laboratory and an international organization) on the basis of a tripartite agreement. The aim was to offer virological analysis to 259 HIV-infected patients.

RESULTS

An alarming proportion (13.9%) of drug resistance among HIV-infected patients was observed.

CONCLUSION

The NRLM contributed to improving the fight against HIV in Madagascar and led to the revision of national therapeutic guidelines. Strengthening reference laboratories has to be a priority in developing countries.

A putative HIV-1 subtype C/CRF11_cpx unique recombinant from South Africa

The HIV epidemic in South Africa is overwhelmingly driven by HIV-1 subtype C viruses. The HIV gag, pol, env (C2-V5) and nef sequences of virus 08MB26ZA, obtained from a 47 year old woman, were studied by phylogenetic analysis, REGA and the jumping Profile Hidden Markov Model (jPHMM) tools. The pol gene was further analyzed for recombination by Simplot. The pol and env sequences were examined for genetic drug resistance mutations and predicted co-receptor usage respectively. There was agreement in the assignment of the gag sequence as pure HIV-1 subtype C by phylogenetic, REGA and jPHMM analyses. The pol sequence clustered with CRF11_cpx and in the J-clade by phylogenetic analysis; and to a CRF11_cpx/subtype C recombinant by REGA. The assignment of pol to CRF11_cpx and subtype C was confirmed by Simplot. The recombinant was of the R5 biotype, with no important drug resistance mutations in the pol region. The epidemiologic and biologic significance of the virus are unknown. The finding suggests that complex viruses are being introduced into South Africa with potential implications for diagnosis. This is apparently the first report from South Africa of a putative unique recombinant involving CRF11_cpx and subtype C genomes.

Genotyping of CCR5 gene, CCR2b and SDF1 variants related to HIV-1 infection in Gabonese subjects

OBJECTIVE

Given the magnitude of the HIV epidemic infection, many viral and human factors were analyzed, and the most decisive was the variant CCR5-Δ32. The presence of a low HIV prevalence (1.8%) in Gabon in the 1990s, compared to neighboring countries, represents a paradox that led us to search for viral and human genetic variants in this country. In this study, only variants of coreceptors and chemokines were investigated.

METHODS

Variants of the coding region of the CCR5 gene were analyzed by denaturing gradient gel electrophoresis, and then variants of SDF1 and CCR2b were determined by polymerase chain reaction-restriction fragment length polymorphism.

RESULTS

Four rare variants of the CCR5 coreceptor were found, while CCR5-Δ32 and CCR5m303 variants were not found. No association with CCR2b-V64I (17%) and SDF1-3'A (2%) variants was determined in relation to HIV-1 infection in Gabonese patients.

CONCLUSION

The paradox of HIV seroprevalence in Gabon, which ended in the 2000s, was not caused by human genetic variants but rather by environmental factors.

Phylogenetic studies of transmission dynamics in generalized HIV epidemics: an essential tool where the burden is greatest?

Efficient and effective HIV prevention measures for generalized epidemics in sub-Saharan Africa have not yet been validated at the population level. Design and impact evaluation of such measures requires fine-scale understanding of local HIV transmission dynamics. The novel tools of HIV phylogenetics and molecular epidemiology may elucidate these transmission dynamics. Such methods have been incorporated into studies of concentrated HIV epidemics to identify proximate and determinant traits associated with ongoing transmission. However, applying similar phylogenetic analyses to generalized epidemics, including the design and evaluation of prevention trials, presents additional challenges. Here we review the scope of these methods and present examples of their use in concentrated epidemics in the context of prevention. Next, we describe the current uses for phylogenetics in generalized epidemics and discuss their promise for elucidating transmission patterns and informing prevention trials. Finally, we review logistic and technical challenges inherent to large-scale molecular epidemiological studies of generalized epidemics and suggest potential solutions.

Spatiotemporal dynamics of the HIV-1 subtype G epidemic in West and Central Africa

The human immunodeficiency virus type 1 (HIV-1) subtype G is the second most prevalent HIV-1 clade in West Africa, accounting for nearly 30% of infections in the region. There is no information about the spatiotemporal dynamics of dissemination of this HIV-1 clade in Africa. To this end, we analyzed a total of 305 HIV-1 subtype G pol sequences isolated from 11 different countries from West and Central Africa over a period of 20 years (1992 to 2011). Evolutionary, phylogeographic and demographic parameters were jointly estimated from sequence data using a Bayesian coalescent-based method. Our analyses indicate that subtype G most probably emerged in Central Africa in 1968 (1956–1976). From Central Africa, the virus was disseminated to West and West Central Africa at multiple times from the middle 1970s onwards. Two subtype G strains probably introduced into Nigeria and Togo between the middle and the late 1970s were disseminated locally and to neighboring countries, leading to the origin of two major western African clades (G_WA-I and G_WA-II). Subtype G clades circulating in western and central African regions displayed an initial phase of exponential growth followed by a decline in growth rate since the early/middle 1990s; but the mean epidemic growth rate of G_WA-I (0.75 year⁻¹) and G_WA-II (0.95 year⁻¹) clades was about two times higher than that estimated for central African lineages (0.47 year⁻¹). Notably, the overall evolutionary and demographic history of G_WA-I and G_WA-II clades was very similar to that estimated for the CRF06_cpx clade circulating in the same region. These results support the notion that the spatiotemporal dissemination dynamics of major HIV-1 clades circulating in western Africa have probably been shaped by the same ecological factors.

TB and HIV in the Central African region: current knowledge and knowledge gaps

PURPOSE

Reliable and comprehensive data on the HIV/AIDS and TB co-pandemics from Central Africa remain scarce. This systematic review provides a comprehensive overview on current and past research activities in the region and provides a basis for future research work to close knowledge gaps.

METHODS

The scientific literature was searched for publications meeting the following search terms: "tuberculosis" or "HIV" or "acquired immunodeficiency syndrome", combined with "Central Africa", or the names of individual countries within the region. Original studies, reviews and case series were included, and a selection of relevant articles was made.

RESULTS

Most research in the field of HIV and TB has been conducted in Cameroon, where the epidemics have been described fairly well. The Democratic Republic of Congo ranked second on the amount of publications, despite the civil wars over the past several decades. Very little has been published on HIV and TB in the other countries, possibly due to the poor infrastructure of health care systems, lack of scientific capacity building or shortage of laboratory equipment.

CONCLUSIONS

Despite the relatively high burden of HIV and TB in the Central African region, the amount of research activities on these topics is limited. A better understanding of the co-epidemics in this region is urgently needed. The occurrence of opportunistic infections, treatment complications and drug resistance in TB and HIV need to be better described; the failure of public health systems needs to be understood, and research infrastructure needs to be developed. Only then will it be possible to turn the tide against the HIV and TB epidemics in this region.

Significant impact of non-B HIV-1 variants genetic diversity in Gabon on plasma HIV-1 RNA quantitation

Evaluations of HIV-1 RNA viral load assays are lacking in Central Africa. The main objective of our study was to assess the reliability of HIV-1 RNA results obtained with three different assays for samples collected in Gabon. A total of 137 plasma specimens were assessed for HIV-1 RNA using the Abbott RealTime HIV-1® and Nuclisens HIV-1 EasyQ® version 2.0 assays. It included HIV-1 non-B samples (n = 113) representing six subtypes, 10 CRFs and 18 URFs from patients infected with HIV-1 and treated with antiretrovirals that were found HIV-1 RNA positive (≥300 copies/ml) with the Generic HIV viral load® assay; and samples (n = 24) from untreated individuals infected with HIV-1 but showing undetectable (<300 copies/ml) results with the Biocentric kit. For samples found positive with the Generic HIV viral load® test, correlation coefficients obtained between the three techniques were relatively low (R = 0.65 between Generic HIV viral load® and Abbott RealTime HIV-1®, 0.50 between Generic HIV viral load® and Nuclisens HIV-1 EasyQ®, and 0.66 between Abbott RealTime HIV-1® and Nuclisens HIV-1 EasyQ®). Discrepancies by at least one log10 were obtained for 19.6%, 33.7%, and 20% of samples, respectively, irrespective of genotype. Most of samples (22/24) from untreated study patients, found negative with the Biocentric kit, were also found negative with the two other techniques. In Central Africa, HIV-1 genetic diversity remains challenging for viral load testing. Further studies are required in the same area to confirm the presence of HIV-1 strains that are not amplified with at least two different viral load assays.

Simian foamy virus in non-human primates and cross-species transmission to humans in Gabon: an emerging zoonotic disease in central Africa?

It is now known that all human retroviruses have a non-human primate counterpart. It has been reported that the presence of these retroviruses in humans is the result of interspecies transmission. Several authors have described the passage of a simian retrovirus, simian foamy virus (SFV), from primates to humans. To better understand this retroviral “zoonosis” in natural settings, we evaluated the presence of SFV in both captive and wild non-human primates and in humans at high risk, such as hunters and people bitten by a non-human primate, in Gabon, central Africa. A high prevalence of SFV was found in blood samples from non-human primates and in bush meat collected across the country. Mandrills were found to be highly infected with two distinct strains of SFV, depending on their geographical location. Furthermore, samples collected from hunters and non-human primate laboratory workers showed clear, extensive cross-species transmission of SFV. People who had been bitten by mandrills, gorillas and chimpanzees had persistent SFV infection with low genetic drift. Thus, SFV is presumed to be transmitted from non-human primates mainly through severe bites, involving contact between infected saliva and blood. In this review, we summarize and discuss our five-year observations on the prevalence and dissemination of SFV in humans and non-human primates in Gabon.

Virological failure rates and HIV-1 drug resistance patterns in patients on first-line antiretroviral treatment in semirural and rural Gabon

Introduction

As antiretroviral treatment (ART) continues to expand in resource-limited countries, the emergence of HIV drug resistance mutations (DRMs) is challenging in these settings. In Gabon (central Africa), no study has yet reported the virological effectiveness of initial ART given through routine HIV care.

Methods

Following the World Health Organization (WHO) recommendations, a cross-sectional study with a one-time HIV-1 RNA viral load (VL) measurement was conducted in Gabon to assess virological failure (VF) defined by a VL result ≥1000 copies/ml and DRMs among adult patients living with non-B HIV-1 strains and receiving first-line non-nucleoside reverse transcriptase inhibitor (NNRTI)-based antiretroviral therapy for at least 12 months. Risk factors associated with VF and DRMs were assessed.

Results

Between March 2010 and March 2011, a total of 375 patients were consecutively enrolled from two decentralized (one semirural and one rural) HIV care centres. Median time on ART was 33.6 months (range, 12–107). Overall, the rate of VF was 41.3% (36.4–46.4). Among viremic patients, 56.7% (80/141) had at least one DRM and 37.6% had dual-class resistance to nucleoside reverse transcriptase inhibitors (NRTIs) and NNRTIs. The most frequent DRMs were K103N/S (46.1%) and M184V/I (37.6%). Thymidine analogue mutations were found in 10.6%. Independent risk factors associated with VF were being followed up at the semirural centre (P=0.033), having experienced unstructured treatment interruptions (P=0.0044), and having low CD4⁺ counts at enrolment (P<0.0001). A longer time on ART (P=0.0008) and being followed up at the rural centre (P=0.021) were risk factors for DRMs.

Conclusions

This is the first study conducted in Gabon providing VF rates and DRM patterns in adult patients receiving first-line ART. In sub-Saharan Africa, where NNRTI-based regimens are recommended as the standard for first-line ART, strengthening virological monitoring together with preventing unplanned treatment interruptions are a global public health priority.

Acute risk for hepatitis E virus infection among HIV-1-positive pregnant women in central Africa

BACKGROUND

Hepatitis E virus (HEV), an enterically transmitted pathogen, is highly endemic in several African countries. Pregnant women are at particularly high risk for acute or severe hepatitis E. In Gabon, a central African country, the prevalence of antibodies to HEV among pregnant women is 14.1%. Recent studies have demonstrated unusual patterns of hepatitis E (chronic hepatitis, cirrhosis) among immunodeficient patients.

FINDINGS

We investigated the prevalence of antibodies to HEV among pregnant women infected with HIV-1 or HTLV-1 in Gabon. Of 243 samples collected, 183 were positive for HIV-1 and 60 for HTLV-1; 16 women (6.6%) had IgG antibodies to HEV. The seroprevalence was higher among HIV-1-infected women (7.1%) than HTLV-1-infected women (5.0%). Moreover, the HIV-1 viral load was significantly increased (p ≤ 0.02) among women with past-HEV exposure (1.3E+05 vs 5.7E+04 copies per ml), whereas no difference was found in HTLV-1 proviral load (9.0E+01 vs 1.1E+03 copies per ml).

CONCLUSIONS

These data provide evidence that HIV-1-infected women are at risk for acute or severe infection if they are exposed to HEV during pregnancy, with an increased viral load.