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1.
Cell ; 187(18): 4981-4995.e14, 2024 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-39059381

RESUMO

Plasmodium falciparum reticulocyte-binding protein homolog 5 (RH5) is the most advanced blood-stage malaria vaccine candidate and is being evaluated for efficacy in endemic regions, emphasizing the need to study the underlying antibody response to RH5 during natural infection, which could augment or counteract responses to vaccination. Here, we found that RH5-reactive B cells were rare, and circulating immunoglobulin G (IgG) responses to RH5 were short-lived in malaria-exposed Malian individuals, despite repeated infections over multiple years. RH5-specific monoclonal antibodies isolated from eight malaria-exposed individuals mostly targeted non-neutralizing epitopes, in contrast to antibodies isolated from five RH5-vaccinated, malaria-naive UK individuals. However, MAD8-151 and MAD8-502, isolated from two malaria-exposed Malian individuals, were among the most potent neutralizers out of 186 antibodies from both cohorts and targeted the same epitopes as the most potent vaccine-induced antibodies. These results suggest that natural malaria infection may boost RH5-vaccine-induced responses and provide a clear strategy for the development of next-generation RH5 vaccines.


Assuntos
Anticorpos Neutralizantes , Anticorpos Antiprotozoários , Antígenos de Protozoários , Vacinas Antimaláricas , Malária Falciparum , Plasmodium falciparum , Humanos , Anticorpos Neutralizantes/imunologia , Plasmodium falciparum/imunologia , Malária Falciparum/imunologia , Malária Falciparum/prevenção & controle , Malária Falciparum/parasitologia , Vacinas Antimaláricas/imunologia , Anticorpos Antiprotozoários/imunologia , Antígenos de Protozoários/imunologia , Imunoglobulina G/imunologia , Imunoglobulina G/sangue , Proteínas de Protozoários/imunologia , Anticorpos Monoclonais/imunologia , Adulto , Linfócitos B/imunologia , Epitopos/imunologia , Feminino , Mali , Proteínas de Transporte/imunologia , Masculino , Adolescente
2.
Immunity ; 57(8): 1769-1779.e4, 2024 Aug 13.
Artigo em Inglês | MEDLINE | ID: mdl-38901428

RESUMO

Many infections, including malaria, are associated with an increase in autoantibodies (AAbs). Prior studies have reported an association between genetic markers of susceptibility to autoimmune disease and resistance to malaria, but the underlying mechanisms are unclear. Here, we performed a longitudinal study of children and adults (n = 602) in Mali and found that high levels of plasma AAbs before the malaria season independently predicted a reduced risk of clinical malaria in children during the ensuing malaria season. Baseline AAb seroprevalence increased with age and asymptomatic Plasmodium falciparum infection. We found that AAbs purified from the plasma of protected individuals inhibit the growth of blood-stage parasites and bind P. falciparum proteins that mediate parasite invasion. Protected individuals had higher plasma immunoglobulin G (IgG) reactivity against 33 of the 123 antigens assessed in an autoantigen microarray. This study provides evidence in support of the hypothesis that a propensity toward autoimmunity offers a survival advantage against malaria.


Assuntos
Autoanticorpos , Imunoglobulina G , Malária Falciparum , Plasmodium falciparum , Humanos , Plasmodium falciparum/imunologia , Autoanticorpos/imunologia , Malária Falciparum/imunologia , Malária Falciparum/parasitologia , Criança , Pré-Escolar , Adulto , Imunoglobulina G/imunologia , Imunoglobulina G/sangue , Feminino , Mali , Masculino , Adolescente , Anticorpos Antiprotozoários/imunologia , Estudos Longitudinais , Lactente , Antígenos de Protozoários/imunologia , Adulto Jovem , Autoantígenos/imunologia , Estudos Soroepidemiológicos , Pessoa de Meia-Idade
3.
N Engl J Med ; 390(17): 1549-1559, 2024 May 02.
Artigo em Inglês | MEDLINE | ID: mdl-38669354

RESUMO

BACKGROUND: Subcutaneous administration of the monoclonal antibody L9LS protected adults against controlled Plasmodium falciparum infection in a phase 1 trial. Whether a monoclonal antibody administered subcutaneously can protect children from P. falciparum infection in a region where this organism is endemic is unclear. METHODS: We conducted a phase 2 trial in Mali to assess the safety and efficacy of subcutaneous administration of L9LS in children 6 to 10 years of age over a 6-month malaria season. In part A of the trial, safety was assessed at three dose levels in adults, followed by assessment at two dose levels in children. In part B of the trial, children were randomly assigned, in a 1:1:1 ratio, to receive 150 mg of L9LS, 300 mg of L9LS, or placebo. The primary efficacy end point, assessed in a time-to-event analysis, was the first P. falciparum infection, as detected on blood smear performed at least every 2 weeks for 24 weeks. A secondary efficacy end point was the first episode of clinical malaria, as assessed in a time-to-event analysis. RESULTS: No safety concerns were identified in the dose-escalation part of the trial (part A). In part B, 225 children underwent randomization, with 75 children assigned to each group. No safety concerns were identified in part B. P. falciparum infection occurred in 36 participants (48%) in the 150-mg group, in 30 (40%) in the 300-mg group, and in 61 (81%) in the placebo group. The efficacy of L9LS against P. falciparum infection, as compared with placebo, was 66% (adjusted confidence interval [95% CI], 45 to 79) with the 150-mg dose and 70% (adjusted 95% CI, 50 to 82) with the 300-mg dose (P<0.001 for both comparisons). Efficacy against clinical malaria was 67% (adjusted 95% CI, 39 to 82) with the 150-mg dose and 77% (adjusted 95% CI, 55 to 89) with the 300-mg dose (P<0.001 for both comparisons). CONCLUSIONS: Subcutaneous administration of L9LS to children was protective against P. falciparum infection and clinical malaria over a period of 6 months. (Funded by the National Institute of Allergy and Infectious Diseases; ClinicalTrials.gov number, NCT05304611.).


Assuntos
Anticorpos Monoclonais Humanizados , Malária Falciparum , Adulto , Criança , Feminino , Humanos , Masculino , Relação Dose-Resposta a Droga , Método Duplo-Cego , Doenças Endêmicas/prevenção & controle , Injeções Subcutâneas , Estimativa de Kaplan-Meier , Malária Falciparum/tratamento farmacológico , Malária Falciparum/epidemiologia , Malária Falciparum/prevenção & controle , Mali/epidemiologia , Plasmodium falciparum , Resultado do Tratamento , Anticorpos Monoclonais Humanizados/administração & dosagem , Anticorpos Monoclonais Humanizados/efeitos adversos , Anticorpos Monoclonais Humanizados/uso terapêutico , Terapia Diretamente Observada , Combinação Arteméter e Lumefantrina/administração & dosagem , Combinação Arteméter e Lumefantrina/uso terapêutico , Adulto Jovem , Pessoa de Meia-Idade
4.
Nature ; 592(7855): 639-643, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33790470

RESUMO

Some Plasmodium falciparum repetitive interspersed families of polypeptides (RIFINs)-variant surface antigens that are expressed on infected erythrocytes1-bind to the inhibitory receptor LAIR1, and insertion of DNA that encodes LAIR1 into immunoglobulin genes generates RIFIN-specific antibodies2,3. Here we address the general relevance of this finding by searching for antibodies that incorporate LILRB1, another inhibitory receptor that binds to ß2 microglobulin and RIFINs through their apical domains4,5. By screening plasma from a cohort of donors from Mali, we identified individuals with LILRB1-containing antibodies. B cell clones isolated from three donors showed large DNA insertions in the switch region that encodes non-apical LILRB1 extracellular domain 3 and 4 (D3D4) or D3 alone in the variable-constant (VH-CH1) elbow. Through mass spectrometry and binding assays, we identified a large set of RIFINs that bind to LILRB1 D3. Crystal and cryo-electron microscopy structures of a RIFIN in complex with either LILRB1 D3D4 or a D3D4-containing antibody Fab revealed a mode of RIFIN-LILRB1 D3 interaction that is similar to that of RIFIN-LAIR1. The Fab showed an unconventional triangular architecture with the inserted LILRB1 domains opening up the VH-CH1 elbow without affecting VH-VL or CH1-CL pairing. Collectively, these findings show that RIFINs bind to LILRB1 through D3 and illustrate, with a naturally selected example, the general principle of creating novel antibodies by inserting receptor domains into the VH-CH1 elbow.


Assuntos
Anticorpos/química , Anticorpos/imunologia , Antígenos de Protozoários/química , Antígenos de Protozoários/imunologia , Microscopia Crioeletrônica , Receptor B1 de Leucócitos Semelhante a Imunoglobulina/química , Plasmodium falciparum/química , Plasmodium falciparum/imunologia , Adolescente , Adulto , Sequência de Aminoácidos , Anticorpos/ultraestrutura , Especificidade de Anticorpos , Antígenos de Protozoários/ultraestrutura , Sítios de Ligação de Anticorpos , Criança , Pré-Escolar , Estudos de Coortes , Humanos , Lactente , Receptor B1 de Leucócitos Semelhante a Imunoglobulina/imunologia , Mali , Modelos Moleculares , Plasmodium falciparum/genética , Plasmodium falciparum/ultraestrutura , Domínios Proteicos , Adulto Jovem
5.
N Engl J Med ; 388(21): 1942-1955, 2023 May 25.
Artigo em Inglês | MEDLINE | ID: mdl-37224196

RESUMO

BACKGROUND: An effective, affordable, multivalent meningococcal conjugate vaccine is needed to prevent epidemic meningitis in the African meningitis belt. Data on the safety and immunogenicity of NmCV-5, a pentavalent vaccine targeting the A, C, W, Y, and X serogroups, have been limited. METHODS: We conducted a phase 3, noninferiority trial involving healthy 2-to-29-year-olds in Mali and Gambia. Participants were randomly assigned in a 2:1 ratio to receive a single intramuscular dose of NmCV-5 or the quadrivalent vaccine MenACWY-D. Immunogenicity was assessed at day 28. The noninferiority of NmCV-5 to MenACWY-D was assessed on the basis of the difference in the percentage of participants with a seroresponse (defined as prespecified changes in titer; margin, lower limit of the 96% confidence interval [CI] above -10 percentage points) or geometric mean titer (GMT) ratios (margin, lower limit of the 98.98% CI >0.5). Serogroup X responses in the NmCV-5 group were compared with the lowest response among the MenACWY-D serogroups. Safety was also assessed. RESULTS: A total of 1800 participants received NmCV-5 or MenACWY-D. In the NmCV-5 group, the percentage of participants with a seroresponse ranged from 70.5% (95% CI, 67.8 to 73.2) for serogroup A to 98.5% (95% CI, 97.6 to 99.2) for serogroup W; the percentage with a serogroup X response was 97.2% (95% CI, 96.0 to 98.1). The overall difference between the two vaccines in seroresponse for the four shared serogroups ranged from 1.2 percentage points (96% CI, -0.3 to 3.1) for serogroup W to 20.5 percentage points (96% CI, 15.4 to 25.6) for serogroup A. The overall GMT ratios for the four shared serogroups ranged from 1.7 (98.98% CI, 1.5 to 1.9) for serogroup A to 2.8 (98.98% CI, 2.3 to 3.5) for serogroup C. The serogroup X component of the NmCV-5 vaccine generated seroresponses and GMTs that met the prespecified noninferiority criteria. The incidence of systemic adverse events was similar in the two groups (11.1% in the NmCV-5 group and 9.2% in the MenACWY-D group). CONCLUSIONS: For all four serotypes in common with the MenACWY-D vaccine, the NmCV-5 vaccine elicited immune responses that were noninferior to those elicited by the MenACWY-D vaccine. NmCV-5 also elicited immune responses to serogroup X. No safety concerns were evident. (Funded by the U.K. Foreign, Commonwealth, and Development Office and others; ClinicalTrials.gov number, NCT03964012.).


Assuntos
Epidemias , Nível de Saúde , Meningite , Vacinas Meningocócicas , Vacinas Conjugadas , Humanos , Gâmbia/epidemiologia , Mali/epidemiologia , Vacinas Conjugadas/administração & dosagem , Vacinas Conjugadas/efeitos adversos , Vacinas Conjugadas/uso terapêutico , Vacinas Meningocócicas/administração & dosagem , Vacinas Meningocócicas/efeitos adversos , Vacinas Meningocócicas/uso terapêutico , Pré-Escolar , Criança , Adolescente , Adulto Jovem , Adulto , Imunogenicidade da Vacina , Injeções Intramusculares , Meningite/epidemiologia , Meningite/prevenção & controle , Epidemias/prevenção & controle
6.
N Engl J Med ; 387(20): 1833-1842, 2022 Nov 17.
Artigo em Inglês | MEDLINE | ID: mdl-36317783

RESUMO

BACKGROUND: CIS43LS is a monoclonal antibody that was shown to protect against controlled Plasmodium falciparum infection in a phase 1 clinical trial. Whether a monoclonal antibody can prevent P. falciparum infection in a region in which the infection is endemic is unknown. METHODS: We conducted a phase 2 trial to assess the safety and efficacy of a single intravenous infusion of CIS43LS against P. falciparum infection in healthy adults in Mali over a 6-month malaria season. In Part A, safety was assessed at three escalating dose levels. In Part B, participants were randomly assigned (in a 1:1:1 ratio) to receive 10 mg of CIS43LS per kilogram of body weight, 40 mg of CIS43LS per kilogram, or placebo. The primary efficacy end point, assessed in a time-to-event analysis, was the first P. falciparum infection detected on blood-smear examination, which was performed at least every 2 weeks for 24 weeks. At enrollment, all the participants received artemether-lumefantrine to clear possible P. falciparum infection. RESULTS: In Part B, 330 adults underwent randomization; 110 were assigned to each trial group. The risk of moderate headache was 3.3 times as high with 40 mg of CIS43LS per kilogram as with placebo. P. falciparum infections were detected on blood-smear examination in 39 participants (35.5%) who received 10 mg of CIS43LS per kilogram, 20 (18.2%) who received 40 mg of CIS43LS per kilogram, and 86 (78.2%) who received placebo. At 6 months, the efficacy of 40 mg of CIS43LS per kilogram as compared with placebo was 88.2% (adjusted 95% confidence interval [CI], 79.3 to 93.3; P<0.001), and the efficacy of 10 mg of CIS43LS per kilogram as compared with placebo was 75.0% (adjusted 95% CI, 61.0 to 84.0; P<0.001). CONCLUSIONS: CIS43LS was protective against P. falciparum infection over a 6-month malaria season in Mali without evident safety concerns. (Funded by the National Institute of Allergy and Infectious Diseases; ClinicalTrials.gov number, NCT04329104.).


Assuntos
Anticorpos Monoclonais Humanizados , Antimaláricos , Malária Falciparum , Adulto , Humanos , Antimaláricos/efeitos adversos , Antimaláricos/uso terapêutico , Combinação Arteméter e Lumefantrina/uso terapêutico , Malária Falciparum/diagnóstico , Malária Falciparum/tratamento farmacológico , Malária Falciparum/prevenção & controle , Mali , Plasmodium falciparum , Anticorpos Monoclonais Humanizados/efeitos adversos , Anticorpos Monoclonais Humanizados/uso terapêutico , Cefaleia/induzido quimicamente
7.
J Infect Dis ; 229(1): 189-197, 2024 Jan 12.
Artigo em Inglês | MEDLINE | ID: mdl-37682871

RESUMO

BACKGROUND: Owing to the increased cases of malaria in older children, the World Health Organization has recently recommended extending seasonal malaria chemoprevention (SMC) to children >5 years of age and using other effective drugs for malaria. In this study, we report the safety and efficacy of dihydroartemisinin-piperaquine (DHA-PQ) for SMC in school-aged children in Mali. METHOD: This randomized, controlled trial included 345 participants aged 6-15 years randomized to receive DHA-PQ, sulfadoxine-pyrimethamine plus amodiaquine (SP-AQ), or no chemoprevention (albendazole) at a 1:1:1 ratio. Four rounds of SMC were conducted from September to December 2021. The participants were assessed 7 days after each round for safety and efficacy of the interventions. RESULTS: Abdominal pain (11.8% vs 29.2%), headache (11.2% vs 19.2%), and vomiting (5.7% vs 15.2%) were frequently reported in the DHA-PQ and SP-AQ arms. On Day 120 of follow up, the incidence of clinical malaria was 0.01 episodes/person-month in the DHA-PQ and SP-AQ arms and 0.17 episodes/person-month in the control arm (P < .0001). Gametocytes were detected in 37 participants in all arms. CONCLUSIONS: Children in DHA-PQ arm reported less adverse events compared to the SP-AQ arm. Both drugs were effective against clinical malaria and infection.


Assuntos
Antimaláricos , Artemisininas , Malária , Piperazinas , Quinolinas , Criança , Humanos , Lactente , Pré-Escolar , Antimaláricos/efeitos adversos , Mali/epidemiologia , Estações do Ano , Malária/epidemiologia , Sulfadoxina/efeitos adversos , Amodiaquina/efeitos adversos , Combinação de Medicamentos , Quimioprevenção/efeitos adversos
8.
Br J Haematol ; 204(1): 337-345, 2024 01.
Artigo em Inglês | MEDLINE | ID: mdl-37728227

RESUMO

Sickle cell disease (SCD) is a life-threatening disease requiring reliable early diagnosis. We assessed the acceptability and diagnostic performances of two rapid diagnostic tests (RDTs) to identify SCD (HbSS, HbSC, HbS/ß-thalassaemia) or SCD carrier (HbS/HbC) in a pilot SCD newborn screening (NBS) strategy in Mali. All consenting delivering women were offered SCD NBS using cord blood sampling on two RDTs (SickleScan® and HemotypeSC®) compared to the high-performance liquid chromatography (HPLC) gold standard to detect SCD states. From April 2021 to August 2021, 4333 delivering women were eligible of whom 96.1% were offered NBS: 1.6% refused, 13.8% delivered before consenting and 84.6% consented; 3648 newborns were diagnosed by HPLC; 1.64% had SCD (0.63% HbSS, 0.85% HbSC, 0.16 HbS/ß-plus-thalassaemia); 21.79% were SCD carrier. To detect accurately SCD, SickleScan® had a sensitivity of 81.67% (95% confidence interval [CI]: 71.88-91.46) and a negative predictive value (NPV) of 99.69% (95% CI: 99.51-99.87); HemotypeSC® had a sensitivity of 78.33% (95% CI: 67.91-88.76) and a NPV of 99.64% (95% CI: 99.44-99.83). To detect SCD carrier: SickleScan® sensitivity was 96.10% (95% CI: 94.75-97.45) and NPV, 98.90% (95% CI: 98.51-99.29); HemotypeSC® sensitivity was 95.22% (95% CI: 93.74-96.70) and NPV, 98.66% (95% CI: 98.24-99.03). Routine SCD NBS was acceptable. Compared with HPLC, both RDTs had reliable diagnostic performances to exclude SCD-free newborns and to identify SCD carriers to be further confirmed. This strategy could be implemented in large-scale NBS programmes.


Assuntos
Anemia Falciforme , Doença da Hemoglobina SC , Humanos , Recém-Nascido , Feminino , Triagem Neonatal/métodos , Testes de Diagnóstico Rápido , Sangue Fetal , Mali , Anemia Falciforme/diagnóstico , Hemoglobina Falciforme/análise
9.
N Engl J Med ; 384(22): 2115-2123, 2021 06 03.
Artigo em Inglês | MEDLINE | ID: mdl-34077644

RESUMO

BACKGROUND: Neisseria meningitidis serogroups A, B, C, W, X, and Y cause outbreaks of meningococcal disease. Quadrivalent conjugate vaccines targeting the A, C, W, and Y serogroups are available. A pentavalent vaccine that also includes serogroup X (NmCV-5) is under development. METHODS: We conducted a phase 2, observer-blinded, randomized, controlled trial involving Malian children 12 to 16 months of age. Participants were assigned in a 2:2:1 ratio to receive nonadjuvanted NmCV-5, alum-adjuvanted NmCV-5, or the quadrivalent vaccine MenACWY-D, administered intramuscularly in two doses 12 weeks apart. Participants were followed for safety for 169 days. Immunogenicity was assessed with an assay for serum bactericidal antibody (SBA) with rabbit complement on days 0, 28, 84, and 112. RESULTS: A total of 376 participants underwent randomization, with 150 assigned to each NmCV-5 group and 76 to the MenACWY-D group; 362 participants received both doses of vaccine. A total of 1% of the participants in the nonadjuvanted NmCV-5 group, 1% of those in the adjuvanted NmCV-5 group, and 4% of those in the MenACWY-D group reported local solicited adverse events; 6%, 5%, and 7% of the participants, respectively, reported systemic solicited adverse events. An SBA titer of at least 128 was seen in 91 to 100% (for all five serotypes) of the participants in the NmCV-5 groups and in 36 to 99% (excluding serogroup X) of those in the MenACWY-D group at day 84 (before the second dose); the same threshold was met in 99 to 100% (for all five serotypes) of the participants in the NmCV-5 groups and in 92 to 100% (excluding serogroup X) of those in the MenACWY-D group at day 112. Immune responses to the nonadjuvanted and adjuvanted NmCV-5 formulations were similar. CONCLUSIONS: No safety concerns were identified with two doses of NmCV-5. A single dose of NmCV-5 elicited immune responses that were similar to those observed with two doses of MenACWY-D. Adjuvanted NmCV-5 provided no discernible benefit over nonadjuvanted NmCV-5. (Funded by the U.K. Foreign, Commonwealth, and Development Office; ClinicalTrials.gov number, NCT03295318.).


Assuntos
Imunogenicidade da Vacina , Infecções Meningocócicas/prevenção & controle , Vacinas Meningocócicas/imunologia , Adjuvantes Imunológicos , Compostos de Alúmen , Feminino , Humanos , Lactente , Injeções Intramusculares , Masculino , Mali , Vacinas Meningocócicas/efeitos adversos , Neisseria meningitidis , Sorogrupo , Método Simples-Cego , Vacinas Conjugadas/imunologia
10.
N Engl J Med ; 385(11): 1005-1017, 2021 09 09.
Artigo em Inglês | MEDLINE | ID: mdl-34432975

RESUMO

BACKGROUND: Malaria control remains a challenge in many parts of the Sahel and sub-Sahel regions of Africa. METHODS: We conducted an individually randomized, controlled trial to assess whether seasonal vaccination with RTS,S/AS01E was noninferior to chemoprevention in preventing uncomplicated malaria and whether the two interventions combined were superior to either one alone in preventing uncomplicated malaria and severe malaria-related outcomes. RESULTS: We randomly assigned 6861 children 5 to 17 months of age to receive sulfadoxine-pyrimethamine and amodiaquine (2287 children [chemoprevention-alone group]), RTS,S/AS01E (2288 children [vaccine-alone group]), or chemoprevention and RTS,S/AS01E (2286 children [combination group]). Of these, 1965, 1988, and 1967 children in the three groups, respectively, received the first dose of the assigned intervention and were followed for 3 years. Febrile seizure developed in 5 children the day after receipt of the vaccine, but the children recovered and had no sequelae. There were 305 events of uncomplicated clinical malaria per 1000 person-years at risk in the chemoprevention-alone group, 278 events per 1000 person-years in the vaccine-alone group, and 113 events per 1000 person-years in the combination group. The hazard ratio for the protective efficacy of RTS,S/AS01E as compared with chemoprevention was 0.92 (95% confidence interval [CI], 0.84 to 1.01), which excluded the prespecified noninferiority margin of 1.20. The protective efficacy of the combination as compared with chemoprevention alone was 62.8% (95% CI, 58.4 to 66.8) against clinical malaria, 70.5% (95% CI, 41.9 to 85.0) against hospital admission with severe malaria according to the World Health Organization definition, and 72.9% (95% CI, 2.9 to 92.4) against death from malaria. The protective efficacy of the combination as compared with the vaccine alone against these outcomes was 59.6% (95% CI, 54.7 to 64.0), 70.6% (95% CI, 42.3 to 85.0), and 75.3% (95% CI, 12.5 to 93.0), respectively. CONCLUSIONS: Administration of RTS,S/AS01E was noninferior to chemoprevention in preventing uncomplicated malaria. The combination of these interventions resulted in a substantially lower incidence of uncomplicated malaria, severe malaria, and death from malaria than either intervention alone. (Funded by the Joint Global Health Trials and PATH; ClinicalTrials.gov number, NCT03143218.).


Assuntos
Amodiaquina/uso terapêutico , Antimaláricos/uso terapêutico , Vacinas Antimaláricas , Malária Falciparum/prevenção & controle , Pirimetamina/uso terapêutico , Sulfadoxina/uso terapêutico , Antimaláricos/efeitos adversos , Burkina Faso/epidemiologia , Quimioprevenção , Terapia Combinada , Método Duplo-Cego , Combinação de Medicamentos , Quimioterapia Combinada , Feminino , Hospitalização/estatística & dados numéricos , Humanos , Lactente , Vacinas Antimaláricas/administração & dosagem , Vacinas Antimaláricas/efeitos adversos , Malária Falciparum/epidemiologia , Malária Falciparum/mortalidade , Masculino , Mali/epidemiologia , Estações do Ano , Convulsões Febris/etiologia
11.
PLoS Pathog ; 18(9): e1010312, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-36121873

RESUMO

Leprosy is a chronic infection of the skin and peripheral nerves caused by Mycobacterium leprae. Despite recent improvements in disease control, leprosy remains an important cause of infectious disability globally. Large-scale genetic association studies in Chinese, Vietnamese and Indian populations have identified over 30 susceptibility loci for leprosy. There is a significant burden of leprosy in Africa, however it is uncertain whether the findings of published genetic association studies are generalizable to African populations. To address this, we conducted a genome-wide association study (GWAS) of leprosy in Malawian (327 cases, 436 controls) and Malian (247 cases, 368 controls) individuals. In that analysis, we replicated four risk loci previously reported in China, Vietnam and India; MHC Class I and II, LACC1 and SLC29A3. We further identified a novel leprosy susceptibility locus at 10q24 (rs2015583; combined p = 8.81 × 10-9; OR = 0.51 [95% CI 0.40 - 0.64]). Using publicly-available data we characterise regulatory activity at this locus, identifying ACTR1A as a candidate mediator of leprosy risk. This locus shows evidence of recent positive selection and demonstrates pleiotropy with established risk loci for inflammatory bowel disease and childhood-onset asthma. A shared genetic architecture for leprosy and inflammatory bowel disease has been previously described. We expand on this, strengthening the hypothesis that selection pressure driven by leprosy has shaped the evolution of autoimmune and atopic disease in modern populations. More broadly, our data highlights the importance of defining the genetic architecture of disease across genetically diverse populations, and that disease insights derived from GWAS in one population may not translate to all affected populations.


Assuntos
Doenças Inflamatórias Intestinais , Hanseníase , Humanos , Criança , Estudo de Associação Genômica Ampla , Predisposição Genética para Doença , Polimorfismo de Nucleotídeo Único , Malaui , Mali , Hanseníase/genética , Proteínas de Transporte de Nucleosídeos/genética
12.
BMC Microbiol ; 24(1): 35, 2024 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-38262985

RESUMO

BACKGROUND: Diarrhoea is a public health problem, especially in developing countries where it is the second leading cause of child mortality. In Low Income Countries like in Mali, self-medication and inappropriate use of antibiotics due to the scarcity of complementary diagnostic systems can lead to the development of multidrug-resistant bacteria causing diarrhoea. The objective of this work was to determine the microorganisms responsible for diarrhoea in children under 15 years of age and to characterize their sensitivity to a panel of antibiotics used in a peri-urban community in Mali. The study involved outpatient children visiting the Yirimadio Community Health Centre and diagnosed with diarrhoea. Stool samples from those patients were collected and analysed by conventional stools culture and the susceptibility to antibiotics of detected bacteria was determined by the disc diffusion method in an agar medium. RESULT: Overall, 554 patients were included. Children under the age of 3 years accounted for 88.8% (492 of 554) of our study population. Two bacterial species were isolated in this study, Escherichia coli 31.8% (176 of 554) and Salmonella 2.9% (16 of 554). In the 176, E. coli strains resistance to amoxicillin and to cotrimoxazole was seen in 93.8% (165 of 176) and 92.6% ( 163 of 176), respectively. The ESBL resistance phenotype accounted for 39,8% (70 of 176) of E. coli. Sixteen (16) strains of Salmonella were found, of which one strain (6.3%) was resistant to amoxicillin and to amoxicillin + clavulanic acid. Another one was resistant to chloramphenicol (6.3%). Two strains of Salmonella were resistant to cotrimoxazole (12.5%) and two others were resistant to cefoxitin (12.5%). CONCLUSIONS: The data suggest that E. coli is frequently involved in diarrhoea in children under 3 years of age in this peri-urban setting of Bamako, Mali, with a high rate of resistance to amoxicillin and cotrimoxazole, the most widely used antibiotics in the management of diarrhoea in this setting.


Assuntos
Antibacterianos , Saúde Pública , Criança , Humanos , Pré-Escolar , Mali , Combinação Trimetoprima e Sulfametoxazol , Escherichia coli , Farmacorresistência Bacteriana , Amoxicilina , Diarreia , Combinação Amoxicilina e Clavulanato de Potássio , Salmonella
13.
Bull World Health Organ ; 102(9): 639-649, 2024 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-39219760

RESUMO

Objective: To test the effect of proactive home visits by trained community health workers (CHWs) on child survival. Methods: We conducted a two arm, parallel, unmasked cluster-randomized trial in 137 village-clusters in rural Mali. From February 2017 to January 2020, 31 761 children enrolled at the trial start or at birth. Village-clusters received either primary care services by CHWs providing regular home visits (intervention) or by CHWs providing care at a fixed site (control). In both arms, user fees were removed and primary health centres received staffing and infrastructure improvements before trial start. Using lifetime birth histories from women aged 15-49 years surveyed annually, we estimated incidence rate ratios (IRR) for intention-to-treat and per-protocol effects on under-five mortality using Poisson regression models. Findings: Over three years, we observed 52 970 person-years (27 332 in intervention arm; 25 638 in control arm). During the trial, 909 children in the intervention arm and 827 children in the control arm died. The under-five mortality rate declined from 142.8 (95% CI: 133.3-152.9) to 56.7 (95% CI: 48.5-66.4) deaths per 1000 live births in the intervention arm; and from 154.3 (95% CI: 144.3-164.9) to 54.9 (95% CI: 45.2-64.5) deaths per 1000 live births in the control arm. Intention-to-treat (IRR: 1.02; 95% CI: 0.88-1.19) and per-protocol estimates (IRR: 1.01; 95% CI: 0.87-1.18) showed no difference between study arms. Conclusion: Though proactive home visits did not reduce under-five mortality, system-strengthening measures may have contributed to the decline in under-five mortality in both arms.


Assuntos
Mortalidade da Criança , Agentes Comunitários de Saúde , Visita Domiciliar , Humanos , Mali/epidemiologia , Agentes Comunitários de Saúde/organização & administração , Feminino , Lactente , Mortalidade da Criança/tendências , Pré-Escolar , Adolescente , Adulto , Pessoa de Meia-Idade , Masculino , Adulto Jovem , Recém-Nascido , Mortalidade Infantil , População Rural , Atenção Primária à Saúde/organização & administração
14.
J Nutr ; 154(8): 2551-2565, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38599389

RESUMO

BACKGROUND: Little is known about costs and cost effectiveness of interventions that integrate wasting prevention into screening for child wasting. OBJECTIVES: This study's objective was to estimate the cost and cost-effectiveness of an intervention that integrated behavior change communication (BCC) and small-quantity lipid-based nutrient supplements (SQ-LNS) into platforms for wasting screening in Burkina Faso (a facility-based platform, where BCC was enhanced compared with standard care) and Mali (a community-based platform, with standard BCC). METHODS: Activity-based costing was used to estimate the cost per child-contact for the intervention and the comparison group, which did not receive the intervention. Costs were ascertained from accounting records, interviews, surveys, and observations. The number of child-contacts was calculated using population size estimates and average attendance rates for each service. Costs per disability-adjusted life year (DALY) averted were estimated using a Markov model populated with data from the parent trials on impact of wasting incidence and treatment coverage. RESULTS: In the intervention group in Burkina Faso, the cost per child-contact of facility-based screening was $0.85 of enhanced BCC was $4.28, and of SQ-LNS was $8.86. In Mali, the cost per child-contact of community-based screening was $0.57, standard BCC was $0.72, and SQ-LNS was $4.14. Although no SQ-LNS costs were incurred in the comparison groups (hence lower total costs), costs per child-contact for screening and BCC were higher because coverage of these services was lower. The intervention package cost $1073 per DALY averted in Burkina Faso and $747 in Mali. CONCLUSIONS: Integration of wasting prevention into screening for child wasting led to higher total costs but lower unit costs than standard screening due to increased coverage. Greater cost-effectiveness could be achieved if BCC were strengthened and led to improved caregiver health and nutrition practices and if screening triggered appropriate use of services and higher treatment coverage.


Assuntos
Análise Custo-Benefício , Síndrome de Emaciação , Humanos , Burkina Faso , Mali , Síndrome de Emaciação/prevenção & controle , Síndrome de Emaciação/economia , Lactente , Programas de Rastreamento/economia , Programas de Rastreamento/métodos , Feminino , Pré-Escolar , Masculino , Anos de Vida Ajustados por Deficiência , Suplementos Nutricionais/economia
15.
BMC Cancer ; 24(1): 81, 2024 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-38225594

RESUMO

BACKGROUND: Breast cancer is the most common cancer in terms of incidence and mortality among women worldwide, including in Africa, and a rapid increase in the number of new cases of breast cancer has recently been observed in sub-Saharan Africa. Oncology is a relatively new discipline in many West African countries, particularly Mali; thus, little is known about the current state of cancer care infrastructure and oncology practices in these countries. METHODS: To describe the challenges related to access to oncology care in Mali, we used a qualitative approach, following the Consolidated Criteria for Reporting Qualitative Research (COREQ). Thirty-eight semistructured interviews were conducted with health professionals treating cancer in Mali (n = 10), women with breast cancer (n = 25), and representatives of associations (n = 3), and 40 participant observations were conducted in an oncology unit in Bamako. We used the theoretical framework on access to health care developed by Levesque et al. a posteriori to organise and analyse the data collected. RESULTS: Access to oncology care is partly limited by the current state of Mali's health infrastructure (technical platform failures, repeated strikes in university hospitals, incomplete free health care and the unavailability of medicines) and exacerbated by the security crisis that has been occurring the country since 2012. The lack of specialist doctors, combined with limited screening campaigns and a centralised and fragmented technical platform in Bamako, is particularly detrimental to breast cancer treatment. Women's lack of awareness, lack of information throughout the treatment process, stereotypes and opposition to amputations all play a significant role in their ability to seek and access quality care, leading some women to therapeutically wander and others to want to leave Mali. It also leaves them in debt and jeopardises the future of their children. However, the high level of trust in doctors, the involvement of international actors, the level of social support and the growing influence of civil society on the issue of cancer also represent great current opportunities to fight cancer in Mali. CONCLUSION: Despite the efforts of successive Malian governments and the commitment of international actors, the provision of health care is still limited in the country, entrenching global inequalities in women's bodies.


Assuntos
Neoplasias da Mama , Criança , Humanos , Feminino , Mali/epidemiologia , Neoplasias da Mama/epidemiologia , Neoplasias da Mama/terapia , Instalações de Saúde , Pesquisa Qualitativa
16.
Malar J ; 23(1): 186, 2024 Jun 13.
Artigo em Inglês | MEDLINE | ID: mdl-38872178

RESUMO

BACKGROUND: In Africa, the relationship between childhood nutritional status and malaria remains complex and difficult to interpret. Understanding it is important in the improvement of malaria control strategies. This study aimed to assess the influence of nutritional status on the occurrence of multiple malaria episodes in children aged 6 to 59 months between 2013 and 2017 living in the village of Dangassa, Mali. METHODS: A community-based longitudinal study was conducted using cross-sectional surveys (CSSs) at the beginning (June) and end (November) of the malaria transmission season associated with passive case detection (PCD) at the Dangassa Community Health Centre. Children with asymptomatic malaria infection during cross-sectional surveys were selected and their malaria episodes followed by PCD. Malaria indicators in person-months were estimated using an ordinal-logistic model repeated on subjects during follow-up periods. RESULTS: The incidence rate (IR) during the period of high transmission (June to October), for 1 episode and for 2 + episodes peaked in 2013 with 65 children (IR = 95.73 per 1000 person-months) and 24 cases (IR = 35.35 per 1000 person-months), respectively. As expected, the risk of multiple episodes occurring during the period of high transmission was 3.23 compared to the period of low transmission after adjusting for other model parameters (95% CI [2.45-4.26], p = 0.000). Children with anaemia were at high risk of having multiple episodes (OR = 1.6, 95% CI [1.12-2.30], p = 0.011). However, the risk of having 2 + episodes for anemic children was higher during the period of low transmission (RR = 1.67, 95% CI [1.15-2.42], p = 0.007) compared to the period of high transmission (RR = 1.58, 95% CI [1.09-2.29], p = 0.016). The trend indicated that anemic and underweight children were significantly associated with multiple malaria episodes during the period of low transmission (p < 0.001). CONCLUSION: Results show that multiple episodes of malaria are significantly related to the nutritional status (anaemia and underweight) of the child during the two transmission seasons and more pronounced during the dry season (period of low transmission). Further research including other malnutrition parameters will be needed to confirm these findings.


Assuntos
Malária , Estado Nutricional , Humanos , Mali/epidemiologia , Lactente , Pré-Escolar , Masculino , Feminino , Malária/epidemiologia , Estudos Longitudinais , Estudos Transversais , Incidência , Prognóstico
17.
BMC Infect Dis ; 24(1): 513, 2024 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-38778266

RESUMO

INTRODUCTION: Long-term exposure to high-risk human papillomavirus (Hr-HPV) is a well-known necessary condition for development of cervical cancer. The aim of this study is to screen for Hr-HPV using vaginal self-sampling, which is a more effective approach to improve women's adherence and increase screening rates. METHODS: This pilot study included a total of 100 Women living with HIV (WLWHIV), recruited from the Center for Listening, Care, Animation, and Counseling of People Living with HIV in Bamako. Hr-HPV genotyping was performed on Self-collected samples using the Cepheid GeneXpert instrument. RESULTS: The median age of WLWHIV was 44 (interquartile range [IQR], 37-50) years. Approximately 92% of the study participants preferred self-sampling at the clinic, and 90% opted to receive result notifications via mobile phone contact. The overall prevalence of Hr-HPV among study participants was 42.6%, and the most frequent Hr-HPV sub-types observed were HPV18/45 (19.1%), HPV31/35/33/52/58 (13.8%), and HPV39/68/56/66 (12.8%), followed by HPV16 (5.3%), and HPV51/59 (5.3%). WLWHIV under 35 years of age had a higher frequency of Hr-HPV compared to their older counterparts, with rates of 30% versus 11.1% (p = 0.03). The duration of antiretroviral treatment showed an inverse association with Hr-HPV negativity, with patients on treatment for 15 (IQR, 10-18) years versus 12 (IQR = 7-14) years for Hr-HPV positive patients (95% CI [1.2-5.8], t = 3.04, p = 0.003). WLWHIV with baseline CD4 T-Cell counts below 200 exhibited a higher frequency of Hr-HPV compared to those with baseline CD4 T-Cell counts above 200 (17.9% versus 1.9%, p = 0.009). However, other demographics and clinical factors, such as marital status, age of sexual debut, parity, education, history of abortion, history of preeclampsia, and cesarean delivery, did not influence the distribution of Hr-HPV genotypes. CONCLUSION: Our findings indicate that WLWHIV under the age of 35 years old exhibited the highest prevalence of Hr-HPV infection, with HPV18/45 being the most prevalent subtype. Additionally, WLWHIV with baseline CD4 T-Cell counts below 200 showed the highest infection rates.


Assuntos
Infecções por HIV , Papillomavirus Humano , Infecções por Papillomavirus , Adulto , Feminino , Humanos , Pessoa de Meia-Idade , Genótipo , Infecções por HIV/virologia , Infecções por HIV/epidemiologia , Papillomavirus Humano/genética , Mali/epidemiologia , Pacientes Ambulatoriais/estatística & dados numéricos , Infecções por Papillomavirus/virologia , Infecções por Papillomavirus/epidemiologia , Projetos Piloto , Prevalência
18.
BMC Womens Health ; 24(1): 180, 2024 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-38491504

RESUMO

BACKGROUND: Female genital mutilation/cutting (FGM/C) is considered a social norm in many African societies, with varying prevalence among countries. Mali is one of the eight countries with very high prevalence of FGM/C in Africa. This study assessed the individual and contextual factors associated with female FGM/C among girls aged 0-14 years in Mali. METHODS: We obtained data from the 2018 Mali Demographic and Health Survey. The prevalence of FGM/C in girls was presented using percentages while a multilevel binary logistic regression analysis was conducted to assess the predictors of FGM/C and the results were presented using adjusted odds ratios with associated 95% confidence intervals (CIs). RESULTS: The results indicate that more than half (72.7%, 95% CI = 70.4-74.8) of women in Mali with daughters had at least one daughter who has gone through circumcision. The likelihood of circumcision of girls increased with age, with women aged 45-49 having the highest odds compared to those aged 15-19 (aOR = 17.68, CI = 7.91-31.79). A higher likelihood of FGM/C in daughters was observed among women who never read newspaper/magazine (aOR = 2.22, 95% CI = 1.27-3.89), compared to those who read newspaper/magazine at least once a week. Compared to women who are not circumcised, those who had been circumcised were more likely to have their daughters circumcised (aOR = 53.98, 95% CI = 24.91-117.00). CONCLUSION: The study revealed the age of mothers, frequency of reading newspaper/magazine, and circumcision status of mothers, as factors associated with circumcision of girls aged 0-14 in Mali. It is, therefore, imperative for existing interventions and new ones to focus on these factors in order to reduce FGM/C in Mali. This will help Mali to contribute to the global efforts of eliminating all harmful practices, such as child, early and forced marriage and female genital mutilation by 2030.


Assuntos
Circuncisão Feminina , Criança , Feminino , Humanos , Mali/epidemiologia , Mães , Núcleo Familiar , Inquéritos e Questionários , Recém-Nascido , Lactente , Pré-Escolar , Adolescente
19.
Public Health Nutr ; 27(1): e58, 2024 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-38311339

RESUMO

OBJECTIVE: The current study aims to determine household-, maternal- and child-related factors influencing nutritional status among children under five in Mali. DESIGN: Quantitative cross-sectional study using secondary data extracted from Mali DHS-VI 2018. SETTING: Urban and rural areas of Mali. PARTICIPANTS: A total of 8908 children participated, with 3999 in the younger age group (0-24 months) and 4909 in the older age group (25-59 months). RESULTS: In the younger age group, the prevalence of stunting, wasting and underweight was 18·8 % (95 % CI%: 17·5, 20·0), 24·6 % (95 % CI: 23·2, 26·0) and 13·2 % (95 % CI: 12·1, 14·3), respectively, while in the older age group, it was 24·9 % (95 % CI: 23·7, 26·2), 22·7 % (95 % CI: 21·5, 24·0) and 5·7 % (95 % CI: 5·0, 6·5), respectively. Being average or large size at birth, having piped source of water, receiving Zn, deworming, high maternal BMI, receiving Fe during pregnancy, higher maternal education and being rich were associated with lower odds of one or more form of undernutrition in both groups. On the other hand, children who were anaemic, drank from a bottle, maternal anaemia, current pregnancy of mothers and living in rural areas were associated with higher odds of stunting, wasting or underweight. Interestingly, children who received Fe supplementation had a higher odds of wasting in the younger group but lower odds of all forms of undernutrition in the older group. CONCLUSIONS: This study emphasised the potential risk factors associated with undernutrition in children. Children who consume non-potable water, have mothers with lower levels of education and BMI and reside in rural areas are more likely to experience undernutrition.


Assuntos
Desnutrição , Estado Nutricional , Recém-Nascido , Feminino , Gravidez , Humanos , Lactente , Idoso , Pré-Escolar , Magreza/epidemiologia , Magreza/etiologia , Estudos Transversais , Mali/epidemiologia , Desnutrição/etiologia , Transtornos do Crescimento/etiologia , Prevalência , Água
20.
BMC Public Health ; 24(1): 43, 2024 01 02.
Artigo em Inglês | MEDLINE | ID: mdl-38166711

RESUMO

BACKGROUND: The uptake of Intermittent Preventive Treatment of malaria in pregnancy using Sulfadoxine-Pyrimethamine (IPTp-SP) remains unacceptably low, with more than two-thirds of pregnant women in sub-Saharan Africa still not accessing the three or more doses recommended by the World Health Organisation (WHO). In contrast, the coverage of Seasonal Malaria Chemoprevention (SMC), a more recent strategy recommended by the WHO for malaria prevention in children under five years living in Sahelian countries with seasonal transmission, including Mali and Burkina-Faso, is high (up to 90%). We hypothesized that IPTp-SP delivery to pregnant women through SMC alongside antenatal care (ANC) will increase IPTp-SP coverage, boost ANC attendance, and increase public health impact. This protocol describes the approach to assess acceptability, feasibility, effectiveness, and cost-effectiveness of the integrated strategy. METHODS AND ANALYSIS: This is a multicentre, cluster-randomized, implementation trial of IPTp-SP delivery through ANC + SMC vs ANC alone in 40 health facilities and their catchment populations (20 clusters per arm). The intervention will consist of monthly administration of IPTp-SP through four monthly rounds of SMC during the malaria transmission season (July to October), for two consecutive years. Effectiveness of the strategy to increase coverage of three or more doses of IPTp-SP (IPTp3 +) will be assessed using household surveys and ANC exit interviews. Statistical analysis of IPT3 + and four or more ANC uptake will use a generalized linear mixed model. Feasibility and acceptability will be assessed through in-depth interviews and focus group discussions with health workers, pregnant women, and women with a child < 12 months. DISCUSSION: This multicentre cluster randomized implementation trial powered to detect a 45% and 22% increase in IPTp-SP3 + uptake in Mali and Burkina-Faso, respectively, will generate evidence on the feasibility, acceptability, effectiveness, and cost-effectiveness of IPTp-SP delivered through the ANC + SMC channel. The intervention is designed to facilitate scalability and translation into policy by leveraging existing resources, while strengthening local capacities in research, health, and community institutions. Findings will inform the local national malaria control policies. TRIAL REGISTRATION: Retrospectively registered on August 11th, 2022; registration # PACTR202208844472053. Protocol v4.0 dated September 04, 2023. Trail sponsor: University of Sciences Techniques and Technologies of Bamako (USTTB), Mali.


Assuntos
Antimaláricos , Malária , Complicações Parasitárias na Gravidez , Criança , Feminino , Gravidez , Humanos , Pré-Escolar , Estações do Ano , Antimaláricos/uso terapêutico , Burkina Faso , Mali , Sulfadoxina/uso terapêutico , Pirimetamina/uso terapêutico , Malária/prevenção & controle , Malária/tratamento farmacológico , Combinação de Medicamentos , Complicações Parasitárias na Gravidez/prevenção & controle , Quimioprevenção , Ensaios Clínicos Controlados Aleatórios como Assunto , Estudos Multicêntricos como Assunto
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