Last data update: Jan 06, 2025. (Total: 48515 publications since 2009)
Records 1-8 (of 8 Records) |
Query Trace: Melchior M[original query] |
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Tuberculosis preventive treatment uptake among adults living with human immunodeficiency virus: Analysis of Zimbabwe population-based human immunodeficiency virus impact assessment 2020
Maphosa T , Mirkovic K , Weber RA , Musuka G , Mapingure MP , Ershova J , Laws R , Dobbs T , Coggin W , Sandy C , Apollo T , Mugurungi O , Melchior M , Farahani MS . Int J STD AIDS 2024 9564624241239186 BACKGROUND: Tuberculosis remains the leading cause of death by an infectious disease among people living with HIV (PLHIV). TB Preventive Treatment (TPT) is a cost-effective intervention known to reduce morbidity and mortality. We used data from ZIMPHIA 2020 to assess TPT uptake and factors associated with its use. METHODOLOGY: ZIMPHIA a cross-sectional household survey, estimated HIV treatment outcomes among PLHIV aged ≥15 years. Randomly selected participants provided demographic and clinical information. We applied multivariable logistic regression models using survey weights. Variances were estimated via the Jackknife series to determine factors associated with TPT uptake. RESULTS: The sample of 2419 PLHIV ≥15 years had 65% females, 44% had no primary education, and 29% lived in urban centers. Overall, 38% had ever taken TPT, including 15% currently taking TPT. Controlling for other variables, those screened for TB at last HIV-related visit, those who visited a TB clinic in the previous 12 months, and those who had HIV viral load suppression were more likely to take TPT. CONCLUSION: The findings show suboptimal TPT coverage among PLHIV. There is a need for targeted interventions and policies to address the barriers to TPT uptake, to reduce TB morbidity and mortality among PLHIV. |
Comparison of COVID-19 pandemic waves in 10 countries in Southern Africa, 2020-2021
Smith-Sreen J , Miller B , Kabaghe AN , Kim E , Wadonda-Kabondo N , Frawley A , Labuda S , Manuel E , Frietas H , Mwale AC , Segolodi T , Harvey P , Seitio-Kgokgwe O , Vergara AE , Gudo ES , Dziuban EJ , Shoopala N , Hines JZ , Agolory S , Kapina M , Sinyange N , Melchior M , Mirkovic K , Mahomva A , Modhi S , Salyer S , Azman AS , McLean C , Riek LP , Asiimwe F , Adler M , Mazibuko S , Okello V , Auld AF . Emerg Infect Dis 2022 28 (13) S93-s104 We used publicly available data to describe epidemiology, genomic surveillance, and public health and social measures from the first 3 COVID-19 pandemic waves in southern Africa during April 6, 2020-September 19, 2021. South Africa detected regional waves on average 7.2 weeks before other countries. Average testing volume 244 tests/million/day) increased across waves and was highest in upper-middle-income countries. Across the 3 waves, average reported regional incidence increased (17.4, 51.9, 123.3 cases/1 million population/day), as did positivity of diagnostic tests (8.8%, 12.2%, 14.5%); mortality (0.3, 1.5, 2.7 deaths/1 million populaiton/day); and case-fatality ratios (1.9%, 2.1%, 2.5%). Beta variant (B.1.351) drove the second wave and Delta (B.1.617.2) the third. Stringent implementation of safety measures declined across waves. As of September 19, 2021, completed vaccination coverage remained low (8.1% of total population). Our findings highlight opportunities for strengthening surveillance, health systems, and access to realistically available therapeutics, and scaling up risk-based vaccination. |
Improving the quality of HIV rapid testing in Ghana using the dried tube specimen-based proficiency testing program
Nkrumah B , Iriemenam NC , Frimpong F , Kalou MB , Botchway B , Adukpo R , Jackson KG , Angra P , Whistler T , Adhikari AP , Ayisi-Addo S , Melchior MA . PLoS One 2022 17 (10) e0264105 BACKGROUND: The introduction of human immunodeficiency virus (HIV) antibody rapid testing (RT) in resource-limited settings has proven to be a successful intervention to increase access to prevention measures and improve timely linkage to care. However, the quality of testing has not always kept pace with the scale-up of this testing strategy. To monitor the accuracy of HIV RT test results, a national proficiency testing (PT) program was rolled out at selected testing sites in Ghana using the dried tube specimen (DTS) approach. METHODS: Between 2015 and 2018, 635 HIV testing sites, located in five regions and supported by the U.S. President's Emergency Plan for AIDS Relief (PEPFAR), were enrolled in the HIV PT program of the Ghana Health Service National AIDS/STI Control Programme. These sites offered various services: HIV Testing and Counselling (HTC), prevention of mother-to-child transmission (PMTCT) and Antiretroviral Treatment (ART). The PT panels, composed of six DTS, were prepared by two regional laboratories, using fully characterized plasma obtained from the regional blood banks and distributed to the testing sites. The results were scored by the PT providers according to the predefined acceptable performance criteria which was set at ≥ 95%. RESULTS: Seven rounds of PT panels were completed successfully over three years. The number of sites enrolled increased from 205 in round 1 (June 2015) to 635 in round 7 (December 2018), with a noticeable increase in Greater Accra and Eastern regions. The average participation rates of enrolled sites ranged from 88.0% to 98.0% across the PT rounds. By round 7, HTC (257/635 (40.5%)) and PMTCT (237/635 (37.3%)) had a larger number of sites that participated in the PT program than laboratory (106/635 (16.7%)) and ART (12/635 (1.9%)) sites. The average testing performance rate improved significantly from 27% in round 1 to 80% in round 7 (p < 0.001). The highest performance rate was observed for ART (100%), HTC (92%), ANC/PMTCT (90%) and Laboratory (89%) in round 5. CONCLUSION: The DTS PT program showed a significant increase in the participation and performance rates during this period. Sub-optimal performances observed was attributed to non-compliance to the national testing algorithm and testing technique. However, the implementation of review meetings, peer-initiated corrective action, supportive supervisory training, and mentorship proved impactful. The decentralized approach to preparing the PT panels ensured ownership by the region and districts. |
Lessons Learned from Programmatic Gains in HIV Service Delivery During the COVID-19 Pandemic - 41 PEPFAR-Supported Countries, 2020.
Fisher KA , Patel SV , Mehta N , Stewart A , Medley A , Dokubo EK , Shang JD , Wright J , Rodas J , Balachandra S , Kitenge F , Mpingulu M , García MC , Bonilla L , Quaye S , Melchior M , Banchongphanith K , Phokhasawad K , Nkanaunena K , Maida A , Couto A , Mizela J , Ibrahim J , Charles OO , Malamba SS , Musoni C , Bolo A , Bunga S , Lolekha R , Kiatchanon W , Bhatia R , Nguyen C , Aberle-Grasse J . MMWR Morb Mortal Wkly Rep 2022 71 (12) 447-452 The U.S. President's Emergency Plan for AIDS Relief (PEPFAR) supports country programs in identifying persons living with HIV infection (PLHIV), providing life-saving treatment, and reducing the spread of HIV in countries around the world (1,2). CDC used Monitoring, Evaluation, and Reporting (MER) data* to assess the extent to which COVID-19 mitigation strategies affected HIV service delivery across the HIV care continuum(†) globally during the first year of the COVID-19 pandemic. Indicators included the number of reported HIV-positive test results, the number of PLHIV who were receiving antiretroviral therapy (ART), and the rates of HIV viral load suppression. Percent change in performance was assessed between countries during the first 3 months of 2020, before COVID-19 mitigation efforts began (January-March 2020), and the last 3 months of the calendar year (October-December 2020). Data were reviewed for all 41 countries to assess total and country-level percent change for each indicator. Then, qualitative data were reviewed among countries in the upper quartile to assess specific strategies that contributed to programmatic gains. Overall, positive percent change was observed in PEPFAR-supported countries in HIV treatment (5%) and viral load suppression (2%) during 2020. Countries reporting the highest gains across the HIV care continuum during 2020 attributed successes to reducing or streamlining facility attendance through strategies such as enhancing index testing (offering of testing to the biologic children and partners of PLHIV)(§) and community- and home-based testing; treatment delivery approaches; and improvements in data use through monitoring activities, systems, and data quality checks. Countries that reported program improvements during the first year of the COVID-19 pandemic offer important information about how lifesaving HIV treatment might be provided during a global public health crisis. |
Apolipoprotein A-I modulates HDL particle size in the absence of apolipoprotein A-II
Melchior JT , Street SE , Vaisar T , Hart R , Jerome J , Kuklenyik Z , Clouet-Foraison N , Thornock C , Bedi S , Shah AS , Segrest JP , Heinecke JW , Davidson WS . J Lipid Res 2021 62 100099 Human high-density lipoproteins (HDL) are a complex mixture of structurally-related nanoparticles that perform distinct physiological functions. We previously showed human HDL containing apolipoprotein A-I (APOA1) but not apolipoprotein A-II (APOA2), designated LpA-I, is composed primarily of two discretely sized populations. Here, we isolated these particles directly from human plasma by antibody affinity chromatography, separated them by high-resolution size exclusion chromatography and performed a deep molecular characterization of each species. The large and small LpA-I populations were spherical with mean diameters of 109 Å and 91 Å, respectively. Unexpectedly, isotope dilution MS/MS with [(15)N]-APOA1 in concert with quantitation of particle concentration by calibrated ion mobility analysis demonstrated that the large particles contained fewer APOA1 molecules than the small particles; the stoichiometries were 3.0 and 3.7 molecules of APOA1 per particle, respectively. MS/MS experiments showed that the protein cargo of large LpA-I particles was more diverse. Human HDL and isolated particles containing both APOA1 and APOA2 exhibit a much wider range and variation of particle sizes than LpA-I, indicating that APOA2 is likely the major contributor to HDL size heterogeneity. We propose a ratchet model based on the trefoil structure of APOA1 whereby the helical cage maintaining particle structure has two 'settings' - large and small - that accounts for these findings. This understanding of the determinants of HDL particle size and protein cargo distribution serves as a basis for determining the roles of HDL subpopulations in metabolism and disease states. |
The impact of antimalarial resistance on the genetic structure of Plasmodium falciparum in the DRC.
Verity R , Aydemir O , Brazeau NF , Watson OJ , Hathaway NJ , Mwandagalirwa MK , Marsh PW , Thwai K , Fulton T , Denton M , Morgan AP , Parr JB , Tumwebaze PK , Conrad M , Rosenthal PJ , Ishengoma DS , Ngondi J , Gutman J , Mulenga M , Norris DE , Moss WJ , Mensah BA , Myers-Hansen JL , Ghansah A , Tshefu AK , Ghani AC , Meshnick SR , Bailey JA , Juliano JJ . Nat Commun 2020 11 (1) 2107 The Democratic Republic of the Congo (DRC) harbors 11% of global malaria cases, yet little is known about the spatial and genetic structure of the parasite population in that country. We sequence 2537 Plasmodium falciparum infections, including a nationally representative population sample from DRC and samples from surrounding countries, using molecular inversion probes - a high-throughput genotyping tool. We identify an east-west divide in haplotypes known to confer resistance to chloroquine and sulfadoxine-pyrimethamine. Furthermore, we identify highly related parasites over large geographic distances, indicative of gene flow and migration. Our results are consistent with a background of isolation by distance combined with the effects of selection for antimalarial drug resistance. This study provides a high-resolution view of parasite genetic structure across a large country in Africa and provides a baseline to study how implementation programs may impact parasite populations. |
The effects of apolipoprotein B depletion on HDL subspecies composition and function
Davidson WS , Heink A , Sexmith H , Melchior JT , Gordon SM , Kuklenyik Z , Woolett L , Barr JR , Jones JI , Toth CA , Shah AS . J Lipid Res 2016 57 (4) 674-86 High density lipoprotein (HDL) cholesterol efflux function may be a more robust biomarker of coronary artery disease risk than HDL cholesterol (HDL-C). To study HDL function, apoB containing lipoproteins are precipitated from serum. Whether apoB precipitation affects HDL subspecies composition and function has not been thoroughly investigated. We studied the effects of four common apoB precipitation methods (polyethylene glycol (PEG), dextran sulfate/MgCl2, heparin sodium/MnCl2 and LipoSep immunoprecipitant (IP)) on HDL subspecies composition, apolipoproteins and function (cholesterol efflux and reduction of LDL oxidation). PEG dramatically shifted the size distribution of HDL and apolipoproteins (assessed by two independent methods), while leaving substantial amounts of reagent in the sample. PEG also changed the distribution of cholesterol efflux and LDL oxidation across size fractions, but not overall efflux across the HDL range. Dextran sulfate/MgCl2 and heparin sodium/MnCl2 did not change the size distribution of HDL subspecies but altered the quantity of a subset of apolipoproteins. LipoSep IP resulted in a shift in the HDL size distribution, but less so than PEG. Thus, each of the apoB precipitation methods affected HDL composition and/or size distribution. We conclude that careful evaluation is needed when selecting apoB depletion methods for existing and future bioassays of HDL function. |
The geography of malaria genetics in the Democratic Republic of Congo: A complex and fragmented landscape.
Carrel M , Patel J , Taylor SM , Janko M , Mwandagalirwa MK , Tshefu AK , Escalante AA , McCollum A , Alam MT , Udhayakumar V , Meshnick S , Emch M . Soc Sci Med 2014 133 233-41 Understanding how malaria parasites move between populations is important, particularly given the potential for malaria to be reintroduced into areas where it was previously eliminated. We examine the distribution of malaria genetics across seven sites within the Democratic Republic of Congo (DRC) and two nearby countries, Ghana and Kenya, in order to understand how the relatedness of malaria parasites varies across space, and whether there are barriers to the flow of malaria parasites within the DRC or across borders. Parasite DNA was retrieved from dried blood spots from 7 Demographic and Health Survey sample clusters in the DRC. Malaria genetic characteristics of parasites from Ghana and Kenya were also obtained. For each of 9 geographic sites (7 DRC, 1 Ghana and 1 Kenya), a pair-wise RST statistic was calculated, indicating the genetic distance between malaria parasites found in those locations. Mapping genetics across the spatial extent of the study area indicates a complex genetic landscape, where relatedness between two proximal sites may be relatively high (RST > 0.64) or low (RST < 0.05), and where distal sites also exhibit both high and low genetic similarity. Mantel's tests suggest that malaria genetics differ as geographic distances increase. Principal Coordinate Analysis suggests that genetically related samples are not co-located. Barrier analysis reveals no significant barriers to gene flow between locations. Malaria genetics in the DRC have a complex and fragmented landscape. Limited exchange of genes across space is reflected in greater genetic distance between malaria parasites isolated at greater geographic distances. There is, however, evidence for close genetic ties between distally located sample locations, indicating that movement of malaria parasites and flow of genes is being driven by factors other than distance decay. This research demonstrates the contributions that spatial disease ecology and landscape genetics can make to understanding the evolutionary dynamics of infectious diseases. |
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