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Search Results: 1 - 10 of 144407 matches for " Avelin F Aghokeng "
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Virological outcome and patterns of HIV-1 drug resistance in patients with 36 months’ antiretroviral therapy experience in Cameroon
Avelin F Aghokeng,Charles Kouanfack,Sabrina Eymard-Duvernay,Christelle Butel
Journal of the International AIDS Society , 2013, DOI: 10.7448/ias.16.1.18004
Abstract: Introduction: The current expansion of antiretroviral treatment (ART) in the developing world without routine virological monitoring still raises concerns on the outcome of the strategy in terms of virological success and drug resistance burden. We assessed the virological outcome and drug resistance mutations in patients with 36 months’ ART experience, and monitored according to the WHO public health approach in Cameroon. Methods: We consecutively recruited between 2008 and 2009 patients attending a national reference clinic in Yaoundé – Cameroon, for their routine medical visits at month 36±2. Observance data and treatment histories were extracted from medical records. Blood samples were collected for viral load (VL) testing and genotyping of drug resistance when HIV-1 RNA≥1000 copies/ml. Results: Overall, 376 HIV-1 infected adults were recruited during the study period. All, but four who received PMTCT, were ART-na ve at treatment initiation, and 371/376 (98.7%) started on a first-line regimen that included 3TC +d4T/AZT+NVP/EFV. Sixty-six (17.6%) patients experienced virological failure (VL≥1000 copies/ml) and 53 carried a resistant virus, thus representing 81.5% (53/65) of the patients who failed. Forty-two out of 53 were resistant to nucleoside and non-nucleoside reverse-transcriptase inhibitors (NRTIs+NNRTIs), one to protease inhibitors (PI) and NNRTIs, two to NRTIs only and eight to NNRTIs only. Among patients with NRTI resistance, 18/44 (40.9%) carried Thymidine Analog Mutations (TAMs), and 13/44 (29.5%) accumulated at least three NRTI resistance mutations. Observed NNRTI resistance mutations affected drugs of the regimen, essentially nevirapine and efavirenz, but several patients (10/51, 19.6%) accumulated mutations that may have compromised etravirine use. Conclusions: We observed a moderate level of virological failure after 36 months of treatment, but a high proportion of patients who failed developed drug resistance. Although we found that for the majority of patients, second-line regimens recommended in Cameroon would be still effective, accumulated resistance mutations are of concern and may compromise future treatment strategies, stressing the need for virological monitoring in resource-limited settings.
Inaccurate Diagnosis of HIV-1 Group M and O Is a Key Challenge for Ongoing Universal Access to Antiretroviral Treatment and HIV Prevention in Cameroon
Avelin F. Aghokeng,Eitel Mpoudi-Ngole,Henriette Dimodi,Arrah Atem-Tambe,Marcel Tongo,Christelle Butel,Eric Delaporte,Martine Peeters
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0007702
Abstract: Increased access to HIV testing is essential in working towards universal access to HIV prevention and treatment in resource-limited countries. We here evaluated currently used HIV diagnostic tests and algorithms in Cameroon for their ability to correctly identify HIV infections.
Characterization of a new simian immunodeficiency virus strain in a naturally infected Pan troglodytes troglodytes chimpanzee with AIDS related symptoms
Lucie Etienne, Eric Nerrienet, Matthew LeBreton, Godwin Bibila, Yacouba Foupouapouognigni, Dominique Rousset, Ahmadou Nana, Cyrille F Djoko, Ubald Tamoufe, Avelin F Aghokeng, Eitel Mpoudi-Ngole, Eric Delaporte, Martine Peeters, Nathan D Wolfe, Ahidjo Ayouba
Retrovirology , 2011, DOI: 10.1186/1742-4690-8-4
Abstract: A male chimpanzee (Cam155), 1.5 years, was seized in southern Cameroon in November 2003 and screened SIV positive during quarantine. Clinical follow-up and biological analyses have been performed for 7 years and showed a significant decline of CD4 counts (1,380 cells/mm3 in 2004 vs 287 in 2009), a severe thrombocytopenia (130,000 cells/mm3 in 2004 vs 5,000 cells/mm3 in 2009), a weight loss of 21.8% from August 2009 to January 2010 (16 to 12.5 kg) and frequent periods of infections with diverse pathogens.DNA from PBMC, leftover from clinical follow-up samples collected in 2004 and 2009, was used to amplify overlapping fragments and sequence two full-length SIVcpzPtt-Cam155 genomes. SIVcpzPtt-Cam155 was phylogenetically related to other SIVcpzPtt from Cameroon (SIVcpzPtt-Cam13) and Gabon (SIVcpzPtt-Gab1). Ten molecular clones 5 years apart, spanning the V1V4 gp120 env region (1,100 bp), were obtained. Analyses of the env region showed positive selection (dN-dS >0), intra-host length variation and extensive amino acid diversity between clones, greater in 2009. Over 5 years, N-glycosylation site frequency significantly increased (p < 0.0001).Here, we describe for the first time the clinical history and viral evolution of a naturally SIV infected P.t.troglodytes chimpanzee. The findings show an increasing viral diversity over time and suggest clinical progression to an AIDS-like disease, showing that SIVcpz can be pathogenic in its host, as previously described in P.t.schweinfurthii. Although studying the impact of SIV infection in wild apes is difficult, efforts should be made to better characterize the pathogenicity of the ancestors of HIV-1 in their natural host and to find out whether SIV infection also plays a role in ape population decline.While non-invasive studies have provided a clear picture on the prevalence and genetic diversity of simian immunodeficiency virus (SIV) infection in wild apes in Central Africa and allowed the tracing of the origins of human immu
Geographic and Temporal Trends in the Molecular Epidemiology and Genetic Mechanisms of Transmitted HIV-1 Drug Resistance: An Individual-Patient- and Sequence-Level Meta-Analysis
Soo-Yon Rhee?,Jose Luis Blanco?,Michael R. Jordan?,Jonathan Taylor?,Philippe Lemey?,Vici Varghese?,Raph L. Hamers?,Silvia Bertagnolio?,Tobias F. Rinke de Wit?,Avelin F. Aghokeng
PLOS Medicine , 2015, DOI: 10.1371/journal.pmed.1001810
Abstract: Background Regional and subtype-specific mutational patterns of HIV-1 transmitted drug resistance (TDR) are essential for informing first-line antiretroviral (ARV) therapy guidelines and designing diagnostic assays for use in regions where standard genotypic resistance testing is not affordable. We sought to understand the molecular epidemiology of TDR and to identify the HIV-1 drug-resistance mutations responsible for TDR in different regions and virus subtypes. Methods and Findings We reviewed all GenBank submissions of HIV-1 reverse transcriptase sequences with or without protease and identified 287 studies published between March 1, 2000, and December 31, 2013, with more than 25 recently or chronically infected ARV-na?ve individuals. These studies comprised 50,870 individuals from 111 countries. Each set of study sequences was analyzed for phylogenetic clustering and the presence of 93 surveillance drug-resistance mutations (SDRMs). The median overall TDR prevalence in sub-Saharan Africa (SSA), south/southeast Asia (SSEA), upper-income Asian countries, Latin America/Caribbean, Europe, and North America was 2.8%, 2.9%, 5.6%, 7.6%, 9.4%, and 11.5%, respectively. In SSA, there was a yearly 1.09-fold (95% CI: 1.05–1.14) increase in odds of TDR since national ARV scale-up attributable to an increase in non-nucleoside reverse transcriptase inhibitor (NNRTI) resistance. The odds of NNRTI-associated TDR also increased in Latin America/Caribbean (odds ratio [OR] = 1.16; 95% CI: 1.06–1.25), North America (OR = 1.19; 95% CI: 1.12–1.26), Europe (OR = 1.07; 95% CI: 1.01–1.13), and upper-income Asian countries (OR = 1.33; 95% CI: 1.12–1.55). In SSEA, there was no significant change in the odds of TDR since national ARV scale-up (OR = 0.97; 95% CI: 0.92–1.02). An analysis limited to sequences with mixtures at less than 0.5% of their nucleotide positions—a proxy for recent infection—yielded trends comparable to those obtained using the complete dataset. Four NNRTI SDRMs—K101E, K103N, Y181C, and G190A—accounted for >80% of NNRTI-associated TDR in all regions and subtypes. Sixteen nucleoside reverse transcriptase inhibitor (NRTI) SDRMs accounted for >69% of NRTI-associated TDR in all regions and subtypes. In SSA and SSEA, 89% of NNRTI SDRMs were associated with high-level resistance to nevirapine or efavirenz, whereas only 27% of NRTI SDRMs were associated with high-level resistance to zidovudine, lamivudine, tenofovir, or abacavir. Of 763 viruses with TDR in SSA and SSEA, 725 (95%) were genetically dissimilar; 38 (5%) formed 19 sequence pairs. Inherent limitations
Early Warning Indicators for HIV Drug Resistance in Cameroon during the Year 2010
Serge C. Billong, Joseph Fokam, Armand S. Nkwescheu, Etienne Kembou, Pascal Milenge, Zephirin Tsomo, Grace Ngute Dion, Avelin F. Aghokeng, Eitel N. Mpoudi, Peter M. Ndumbe, Vittorio Colizzi, Jean B. Elat Nfetam
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0036777
Abstract: Background Rapid scale-up of antiretroviral therapy (ART) in resource-limited settings is accompanied with an increasing risk of HIV drug resistance (HIVDR), which in turn could compromise the performance of national ART rollout programme. In order to sustain the effectiveness of ART in a resource-limited country like Cameroon, HIVDR early warning indicators (EWI) may provide relevant corrective measures to support the control and therapeutic management of AIDS. Methods A retrospective study was conducted in 2010 among 40 ART sites (12 Approved Treatment Centers and 28 Management Units) distributed over the 10 regions of Cameroon. Five standardized EWIs were selected for the evaluation using data from January through December, among which: (1) Good ARV prescribing practices: target = 100%; (2) Patient lost to follow-up: target ≤20%; (3) Patient retention on first line ART: target ≥70%; (4) On-time drug pick-up: target ≥90%; (5) ARV drug supply continuity: target = 100%. Analysis was performed using a Data Quality Assessment tool, following WHO protocol. Results The number of sites attaining the required performance are: 90% (36/40) for EWI1, 20% (8/40) for EWI2; 20% (8/40) for EWI3; 0% (0/37) for EWI4; and 45% (17/38) for EWI 5. ARV prescribing practices were in conformity with the national guidelines in almost all the sites, whereas patient adherence to ART (EWI2, EWI3, and EWI4) was very low. A high rate of patients was lost-to-follow-up and others failing first line ART before 12 months of initiation. Discontinuity in drug supply observed in about half of the sites may negatively impact ARV prescription and patient adherence. These poor ART performances may also be due to low number of trained staff and community disengagement. Conclusions The poor performance of the national ART programme, due to patient non-adherence and drug stock outs, requires corrective measures to limit risks of HIVDR emergence in Cameroon.
Population-Based Monitoring of Emerging HIV-1 Drug Resistance on Antiretroviral Therapy and Associated Factors in a Sentinel Site in Cameroon: Low Levels of Resistance but Poor Programmatic Performance
Serge C. Billong, Joseph Fokam, Avelin F. Aghokeng, Pascal Milenge, Etienne Kembou, Ibile Abessouguie, Flore Beatrice Meva’a-Onglene, Anne C. Zoung-Kanyi. Bissek, Vittorio Colizzi, Eitel N. Mpoudi, Jean-Bosco N. Elat, Koulla S. Shiro
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0072680
Abstract: Background Scale-up of antiretroviral therapy (ART) in resource-limited settings has drastically reduced HIV-related morbidity and mortality. However, challenges in long-term ART, adherence and HIV drug resistance (HIVDR) itself, require monitoring to limit HIVDR emergence among ART-experienced populations, in order to ensure regimen efficacy. Methods A longitudinal study was conducted from 2009–2011 in a cohort of 141 HIV-infected adult patients (aged >21) at the national social insurance centre hospital in Yaounde, Cameroon. As per-WHO HIVDR protocol, HIV-1 protease-reverse transcriptase genotyping was performed at baseline and at endpoint (12 months) on first-line ART using ViroSeq? Genotyping kit. Results At baseline, a prevalence of 3.6% (5/139) HIVDR was observed [protease inhibitors M46I (1/5), G73A (1/5), L90LM (1/5); nucleoside reverse transcriptase inhibitors: M184V (1/5), T215F (1/5); non-nucleoside reverse transcriptase inhibitors: K103N (1/5), Y181Y/C (2/5), M230ML (1/5)]. At endpoint, 54.0% (76) patients were followed-up, 9.2% (13) died, and 3.5% (5) transferred, 38.5% (47) lost to follow-up (LTFU). 69.7% (53/76) of those followed-up had viremia <40 copies/ml and 90.8% (69/76) <1000 copies/ml. 4/7 patients with viremia ≥1000 copies/ml harbored HIVDR (prevalence: 5.3%; 4/76), with M184V/I (4/4) and K103K/N (3/4) being the most prevalent mutations. LTFU was favored by costs for consultation/laboratory tests, drug shortages, workload (physician/patient ratio: 1/180) and community disengagement. Conclusions Low levels of HIVDR at baseline and at endpoint suggest a probable effectiveness of ART regimens used in Cameroon. However the possible high rate of HIVDR among LTFUs limited the strengths of our findings. Evaluating HIVDR among LTFU, improving adherence, task shifting, subsidizing/harmonizing costs for routine follow-up, are urgent measures to ensure an improved success of the country ART performance.
Susceptibility to Transmitting HIV in Patients Initiating Antiretroviral Therapy in Rural District Hospitals in Cameroon (Stratall ANRS 12110/ESTHER Trial)
Gilbert Ndziessi, Julien Cohen, Charles Kouanfack, Fabienne Marcellin, Maria Patrizia Carierri, Gabrièle Laborde-Balen, Camélia Protopopescu, Avelin Fobang Aghokeng, Jean-Paul Moatti, Bruno Spire, Eric Delaporte, Christian Laurent, Sylvie Boyer, for the Stratall ANRS 12110 / ESTHER Study Group
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0062611
Abstract: Objectives Using cohort data nested in a randomized trial conducted in Cameroon, this study aimed to investigate time trends and predictors of the susceptibility to transmitting HIV during the first 24 months of treatment. Methods The outcome, susceptibility to transmitting HIV, was defined as reporting inconsistent condom use and experiencing incomplete virological suppression. Mixed logistic regressions were performed to identify predictors of this outcome among 250 patients reporting to have had sexual relationships either with HIV-negative or unknown HIV status partner(s). Results Despite an initial decrease from 76% at M0 to 50% at M6, the rate of inconsistent condom use significantly increased from M12 (59%) to M24 (66%) (p = 0.017). However, the proportion of patients susceptible to transmitting HIV significantly decreased over follow-up from 76% at M0, to 50% at M6, 31% at M12 and 27% at M24 (p<0.001). After controlling for age, gender and intervention group, we found that perceiving healthcare staff’s readiness to listen as poor (adjusted odds ratios (AOR) [95% Confidence Interval (CI)] = 1.87 [1.01–3.46]), reporting to have sexual relationships more than once per week (AOR [95%CI] = 2.52 [1.29–4.93]), having more than one sexual partner (AOR [95%CI] = 2.53 [1.21–5.30]) and desiring a/another child (AOR [95%CI] = 2.07 [1.10–3.87]) were all associated with a higher risk of being susceptible to transmitting HIV. Conversely, time since ART initiation (AOR [95%CI] = 0.66 [0.53–0.83] for an extra 6 months and ART adherence (AOR [95%CI] = 0.33 [0.15–0.72]) were significantly associated with a lower risk of being susceptible to transmitting HIV. Conclusions The decrease observed in the susceptibility to transmitting HIV suggests that fear of behavioural disinhibition should not be a barrier to universal access to ART. However, developing adequate preventive interventions matching patients’ expectations -like the desire to have children- and strengthening healthcare staff’s counselling skills are urgently needed to maximize the impact of ART in slowing the HIV epidemic.
Lower semicontinuity of weak supersolutions to the porous medium equation
Benny Avelin,Teemu Lukkari
Mathematics , 2013,
Abstract: Weak supersolutions to the porous medium equation are defined by means of smooth test functions under an integral sign. We show that nonnegative weak supersolutions become lower semicontinuous after redefinition on a set of measure zero. This shows that weak supersolutions belong to a class of supersolutions defined by a comparison principle.
Characterizations of interior polar sets for the degenerate p-parabolic equation
Benny Avelin,Olli Saari
Mathematics , 2015,
Abstract: This paper deals with different characterizations of sets of nonlinear parabolic capacity zero, with respect to the parabolic p-Laplace equation. Specifically we prove that certain interior polar sets can be characterized by sets of zero nonlinear parabolic capacity. Furthermore we prove that zero capacity sets are removable for bounded supersolutions and that sets of zero capacity have a relation to a certain parabolic Hausdorff measure.
A comparison principle for the porous medium equation and its consequences
Benny Avelin,Teemu Lukkari
Mathematics , 2015,
Abstract: We prove a comparison principle for the porous medium equation in more general open sets in $\mathbb{R}^{n+1}$ than space-time cylinders. We apply this result in two related contexts: we establish a connection between a potential theoretic notion of the obstacle problem and a notion based on a variational inequality. We also prove the basic properties of the PME capacity, in particular that there exists a capacitary extremal which gives the capacity for compact sets.
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