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1.
Nature ; 602(7895): 106-111, 2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-34883497

RESUMO

Host genetic factors can confer resistance against malaria1, raising the question of whether this has led to evolutionary adaptation of parasite populations. Here we searched for association between candidate host and parasite genetic variants in 3,346 Gambian and Kenyan children with severe malaria caused by Plasmodium falciparum. We identified a strong association between sickle haemoglobin (HbS) in the host and three regions of the parasite genome, which is not explained by population structure or other covariates, and which is replicated in additional samples. The HbS-associated alleles include nonsynonymous variants in the gene for the acyl-CoA synthetase family member2-4 PfACS8 on chromosome 2, in a second region of chromosome 2, and in a region containing structural variation on chromosome 11. The alleles are in strong linkage disequilibrium and have frequencies that covary with the frequency of HbS across populations, in particular being much more common in Africa than other parts of the world. The estimated protective effect of HbS against severe malaria, as determined by comparison of cases with population controls, varies greatly according to the parasite genotype at these three loci. These findings open up a new avenue of enquiry into the biological and epidemiological significance of the HbS-associated polymorphisms in the parasite genome and the evolutionary forces that have led to their high frequency and strong linkage disequilibrium in African P. falciparum populations.


Assuntos
Genótipo , Hemoglobina Falciforme/genética , Adaptação ao Hospedeiro/genética , Malária Falciparum/sangue , Malária Falciparum/parasitologia , Parasitos/genética , Plasmodium falciparum/genética , Alelos , Animais , Criança , Feminino , Gâmbia/epidemiologia , Genes de Protozoários/genética , Humanos , Quênia/epidemiologia , Desequilíbrio de Ligação , Malária Falciparum/epidemiologia , Masculino , Polimorfismo Genético
2.
PLoS Genet ; 19(9): e1010910, 2023 09.
Artigo em Inglês | MEDLINE | ID: mdl-37708213

RESUMO

Blood group O is associated with protection against severe malaria and reduced size and stability of P. falciparum-host red blood cell (RBC) rosettes compared to non-O blood groups. Whether the non-O blood groups encoded by the specific ABO genotypes AO, BO, AA, BB and AB differ in their associations with severe malaria and rosetting is unknown. The A and B antigens are host RBC receptors for rosetting, hence we hypothesized that the higher levels of A and/or B antigen on RBCs from AA, BB and AB genotypes compared to AO/BO genotypes could lead to larger rosettes, increased microvascular obstruction and higher risk of malaria pathology. We used a case-control study of Kenyan children and in vitro adhesion assays to test the hypothesis that "double dose" non-O genotypes (AA, BB, AB) are associated with increased risk of severe malaria and larger rosettes than "single dose" heterozygotes (AO, BO). In the case-control study, compared to OO, the double dose genotypes consistently had higher odds ratios (OR) for severe malaria than single dose genotypes, with AB (OR 1.93) and AO (OR 1.27) showing most marked difference (p = 0.02, Wald test). In vitro experiments with blood group A-preferring P. falciparum parasites showed that significantly larger rosettes were formed with AA and AB host RBCs compared to OO, whereas AO and BO genotypes rosettes were indistinguishable from OO. Overall, the data show that ABO genotype influences P. falciparum rosetting and support the hypothesis that double dose non-O genotypes confer a greater risk of severe malaria than AO/BO heterozygosity.


Assuntos
Malária Falciparum , Malária , Criança , Humanos , Sistema ABO de Grupos Sanguíneos/genética , Plasmodium falciparum/genética , Estudos de Casos e Controles , Quênia , Genótipo , Malária Falciparum/genética
3.
Malar J ; 19(1): 322, 2020 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-32883291

RESUMO

BACKGROUND: Few recent descriptions of severe childhood malaria have been published from high-transmission regions. In the current study, the clinical epidemiology of severe malaria in Mbale, Eastern Uganda, is described, where the entomological inoculation rate exceeds 100 infective bites per year. METHODS: A prospective descriptive study was conducted to determine the prevalence, clinical spectrum and outcome of severe Plasmodium falciparum malaria at Mbale Regional Referral Hospital in Eastern Uganda. All children aged 2 months-12 years who presented on Mondays to Fridays between 8.00 am and 5.00 pm from 5th May 2011 until 30th April 2012 were screened for parasitaemia. Clinical and laboratory data were then collected from all P. falciparum positive children with features of WHO-defined severe malaria by use of a standardized proforma. RESULTS: A total of 10 208 children were screened of which 6582 (64%) had a positive blood film. Of these children, 662 (10%) had clinical features of severe malaria and were consented for the current study. Respiratory distress was the most common severity feature (554; 83.7%), while 365/585 (62.4%) had hyperparasitaemia, 177/662 (26.7%) had clinical jaundice, 169 (25.5%) had severe anaemia, 134/660 (20.2%) had hyperlactataemia (lactate ≥ 5 mmol/L), 93 (14.0%) had passed dark red or black urine, 52 (7.9%) had impaired consciousness and 49/662 (7.4%) had hypoxaemia (oxygen saturations < 90%). In-hospital mortality was 63/662 (9.5%) overall but was higher in children with either cerebral malaria (33.3%) or severe anaemia (19.5%). Factors that were independently associated with mortality on multivariate analysis included severe anaemia [odds ratio (OR) 5.36; 2.16-1.32; P = 0.0002], hyperlactataemia (OR 3.66; 1.72-7.80; P = 0.001), hypoxaemia (OR) 3.64 (95% CI 1.39-9.52; P = 0.008), and hepatomegaly (OR 2.29; 1.29-4.06; P = 0.004). No independent association was found between mortality and either coma or hyperparasitaemia. CONCLUSIONS: Severe childhood malaria remains common in Eastern Uganda where it continues to be associated with high mortality. An unusually high proportion of children with severe malaria had jaundice or gave a history of having recently passed dark red or black urine, an issue worthy of further investigation.


Assuntos
Anemia/epidemiologia , Malária Cerebral/epidemiologia , Malária Falciparum/epidemiologia , Parasitemia/epidemiologia , Anemia/complicações , Anemia/mortalidade , Anemia/parasitologia , Criança , Pré-Escolar , Feminino , Hospitais , Humanos , Lactente , Malária Cerebral/complicações , Malária Cerebral/mortalidade , Malária Cerebral/parasitologia , Malária Falciparum/complicações , Malária Falciparum/mortalidade , Malária Falciparum/parasitologia , Masculino , Parasitemia/complicações , Parasitemia/mortalidade , Parasitemia/parasitologia , Prevalência , Estudos Prospectivos , Uganda/epidemiologia
4.
Am J Hum Genet ; 98(6): 1092-1100, 2016 Jun 02.
Artigo em Inglês | MEDLINE | ID: mdl-27236921

RESUMO

Bacteremia (bacterial bloodstream infection) is a major cause of illness and death in sub-Saharan Africa but little is known about the role of human genetics in susceptibility. We conducted a genome-wide association study of bacteremia susceptibility in more than 5,000 Kenyan children as part of the Wellcome Trust Case Control Consortium 2 (WTCCC2). Both the blood-culture-proven bacteremia case subjects and healthy infants as controls were recruited from Kilifi, on the east coast of Kenya. Streptococcus pneumoniae is the most common cause of bacteremia in Kilifi and was thus the focus of this study. We identified an association between polymorphisms in a long intergenic non-coding RNA (lincRNA) gene (AC011288.2) and pneumococcal bacteremia and replicated the results in the same population (p combined = 1.69 × 10(-9); OR = 2.47, 95% CI = 1.84-3.31). The susceptibility allele is African specific, derived rather than ancestral, and occurs at low frequency (2.7% in control subjects and 6.4% in case subjects). Our further studies showed AC011288.2 expression only in neutrophils, a cell type that is known to play a major role in pneumococcal clearance. Identification of this novel association will further focus research on the role of lincRNAs in human infectious disease.


Assuntos
Bacteriemia/genética , Pneumonia Pneumocócica/genética , Polimorfismo Genético/genética , RNA Longo não Codificante/genética , Streptococcus pneumoniae/genética , Adolescente , Bacteriemia/microbiologia , Bacteriemia/patologia , Estudos de Casos e Controles , Criança , Pré-Escolar , Estudo de Associação Genômica Ampla , Humanos , Lactente , Recém-Nascido , Quênia/epidemiologia , Pneumonia Pneumocócica/microbiologia , Pneumonia Pneumocócica/patologia , Fatores de Risco
5.
Am J Hematol ; 93(3): 363-370, 2018 03.
Artigo em Inglês | MEDLINE | ID: mdl-29168218

RESUMO

Sickle cell anemia (SCA) is the commonest severe monogenic disorders of humans. The disease has been highly characterized in high-income countries but not in sub-Saharan Africa where SCA is most prevalent. We conducted a retrospective cohort study of all children 0-13 years admitted from within a defined study area to Kilifi County Hospital in Kenya over a five-year period. Children were genotyped for SCA retrospectively and incidence rates calculated with reference to population data. Overall, 576 of 18,873 (3.1%) admissions had SCA of whom the majority (399; 69.3%) were previously undiagnosed. The incidence of all-cause hospital admission was 57.2/100 person years of observation (PYO; 95%CI 52.6-62.1) in children with SCA and 3.7/100 PYO (95%CI 3.7-3.8) in those without SCA (IRR 15.3; 95%CI 14.1-16.6). Rates were higher for the majority of syndromic diagnoses at all ages beyond the neonatal period, being especially high for severe anemia (hemoglobin <50 g/L; IRR 58.8; 95%CI 50.3-68.7), stroke (IRR 486; 95%CI 68.4-3,450), bacteremia (IRR 23.4; 95%CI 17.4-31.4), and for bone (IRR 607; 95%CI 284-1,300), and joint (IRR 80.9; 95%CI 18.1-362) infections. The use of an algorithm based on just five clinical features would have identified approximately half of all SCA cases among hospital-admitted children with a number needed to test to identify each affected patient of only fourteen. Our study illustrates the clinical epidemiology of SCA in a malaria-endemic environment without specific interventions. The targeted testing of hospital-admitted children using the Kilifi Algorithm provides a pragmatic approach to early diagnosis in high-prevalence countries where newborn screening is unavailable.


Assuntos
Anemia Falciforme/epidemiologia , Adolescente , Anemia Falciforme/diagnóstico , Bacteriemia/epidemiologia , Criança , Pré-Escolar , Comorbidade , Diagnóstico Tardio/prevenção & controle , Diagnóstico Tardio/estatística & dados numéricos , Países em Desenvolvimento , Testes Diagnósticos de Rotina , Suscetibilidade a Doenças , Diagnóstico Precoce , Feminino , Humanos , Lactente , Recém-Nascido , Quênia/epidemiologia , Malária/epidemiologia , Masculino , Desnutrição/epidemiologia , Meningite/epidemiologia , Admissão do Paciente , Vigilância da População , Estudos Retrospectivos , Acidente Vascular Cerebral/epidemiologia
6.
Clin Infect Dis ; 64(7): 939-946, 2017 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-28362936

RESUMO

BACKGROUND: In the Fluid Expansion as a Supportive Treatment (FEAST) trial, an unexpectedly high proportion of participants from eastern Uganda presented with blackwater fever (BWF). METHODS: We describe the prevalence and outcome of BWF among trial participants and compare the prevalence of 3 malaria-protective red blood cell polymorphisms in BWF cases vs both trial (non-BWF) and population controls. RESULTS: Of 3170 trial participants, 394 (12.4%) had BWF. The majority (318 [81.0%]) presented in eastern Uganda and were the subjects of further analysis. BWF cases typically presented with both clinical jaundice (254/318 [80%]) and severe anemia (hemoglobin level <5 g/dL) (238/310 [77%]). Plasmodium falciparum parasitemia was less frequent than in non-BWF controls, but a higher proportion were positive for P. falciparum histidine rich protein 2 (192/246 [78.0%]) vs 811/1154 [70.3%]; P = .014), suggesting recent antimalarial treatment. Overall, 282 of 318 (88.7%) received transfusions, with 94 of 282 (33.3%) and 9 of 282 (3.4%) receiving 2 or 3 transfusions, respectively. By day 28, 39 of 318 (12.3%) BWF cases and 154 of 1554 (9.9%) non-BWF controls had died (P = .21), and 7 of 255 (3.0%) vs 13/1212 (1%), respectively, had severe anemia (P = .036). We found no association with G6PD deficiency. The prevalence of both the sickle cell trait (10/218 [4.6%]) and homozygous α+thalassemia (8/216 [3.7%]) were significantly lower among cases than among population controls (334/2123 [15.7%] and 141/2114 [6.6%], respectively), providing further support for the role of malaria. CONCLUSIONS: We report the emergence of BWF in eastern Uganda, a condition that, according to local investigators, was rare until the last 7 years. We speculate that this might relate to the introduction of artemisinin-based combination therapies. Further studies investigating this possibility are urgently required.


Assuntos
Febre Hemoglobinúrica/diagnóstico , Febre Hemoglobinúrica/epidemiologia , Fatores Etários , Biomarcadores , Febre Hemoglobinúrica/complicações , Febre Hemoglobinúrica/parasitologia , Pré-Escolar , Eritrócitos/metabolismo , Eritrócitos/parasitologia , Feminino , Glucosefosfato Desidrogenase/genética , Hemoglobinopatias/complicações , Hemoglobinopatias/genética , Humanos , Lactente , Masculino , Mutação , Avaliação de Resultados da Assistência ao Paciente , Fenótipo , Polimorfismo Genético , Prevalência , Índice de Gravidade de Doença , Avaliação de Sintomas , Uganda/epidemiologia , Urinálise
7.
Mol Biol Evol ; 33(5): 1188-204, 2016 05.
Artigo em Inglês | MEDLINE | ID: mdl-26744416

RESUMO

Genome-wide searches for loci involved in human resistance to malaria are currently being conducted on a large scale in Africa using case-control studies. Here, we explore the utility of an alternative approach-"environmental correlation analysis, ECA," which tests for clines in allele frequencies across a gradient of an environmental selection pressure-to identify genes that have historically protected against death from malaria. We collected genotype data from 12,425 newborns on 57 candidate malaria resistance loci and 9,756 single nucleotide polymorphisms (SNPs) selected at random from across the genome, and examined their allele frequencies for geographic correlations with long-term malaria prevalence data based on 84,042 individuals living under different historical selection pressures from malaria in coastal Kenya. None of the 57 candidate SNPs showed significant (P < 0.05) correlations in allele frequency with local malaria transmission intensity after adjusting for population structure and multiple testing. In contrast, two of the random SNPs that had highly significant correlations (P < 0.01) were in genes previously linked to malaria resistance, namely, CDH13, encoding cadherin 13, and HS3ST3B1, encoding heparan sulfate 3-O-sulfotransferase 3B1. Both proteins play a role in glycoprotein-mediated cell-cell adhesion which has been widely implicated in cerebral malaria, the most life-threatening form of this disease. Other top genes, including CTNND2 which encodes δ-catenin, a molecular partner to cadherin, were significantly enriched in cadherin-mediated pathways affecting inflammation of the brain vascular endothelium. These results demonstrate the utility of ECA in the discovery of novel genes and pathways affecting infectious disease.


Assuntos
Malária/genética , Adolescente , Alelos , Estudos de Casos e Controles , Criança , Pré-Escolar , Resistência à Doença/genética , Meio Ambiente , Frequência do Gene , Estudos de Associação Genética/métodos , Predisposição Genética para Doença , Humanos , Lactente , Recém-Nascido , Quênia/epidemiologia , Malária/epidemiologia , Malária/prevenção & controle , Malária Falciparum/epidemiologia , Malária Falciparum/genética , Malária Falciparum/prevenção & controle , Plasmodium falciparum/genética , Plasmodium falciparum/microbiologia , Polimorfismo de Nucleotídeo Único , Seleção Genética
8.
Blood ; 123(13): 2008-16, 2014 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-24478401

RESUMO

Haptoglobin (Hp) scavenges free hemoglobin following malaria-induced hemolysis. Few studies have investigated the relationship between the common Hp variants and the risk of severe malaria, and their results are inconclusive. We conducted a case-control study of 996 children with severe Plasmodium falciparum malaria and 1220 community controls and genotyped for Hp, hemoglobin (Hb) S heterozygotes, and α(+)thalassemia. Hb S heterozygotes and α(+)thalassemia homozygotes were protected from severe malaria (odds ratio [OR], 0.12; 95% confidence interval [CI], 0.07-0.18 and OR, 0.69; 95% CI, 0.53-0.91, respectively). The risk of severe malaria also varied by Hp genotype: Hp2-1 was associated with the greatest protection against severe malaria and Hp2-2 with the greatest risk. Meta-analysis of the current and published studies suggests that Hp2-2 is associated with increased risk of severe malaria compared with Hp2-1. We found a significant interaction between Hp genotype and α(+)thalassemia in predicting risk of severe malaria: Hp2-1 in combination with heterozygous or homozygous α(+)thalassemia was associated with protection from severe malaria (OR, 0.73; 95% CI, 0.54-0.99 and OR, 0.48; 95% CI, 0.32-0.73, respectively), but α(+)thalassemia in combination with Hp2-2 was not protective. This epistatic interaction together with varying frequencies of α(+)thalassemia across Africa may explain the inconsistent relationship between Hp genotype and malaria reported in previous studies.


Assuntos
Epistasia Genética , Haptoglobinas/genética , Malária Falciparum/epidemiologia , Malária Falciparum/genética , Talassemia alfa/epidemiologia , Talassemia alfa/genética , Estudos de Casos e Controles , Criança , Pré-Escolar , Feminino , Predisposição Genética para Doença , Genótipo , Humanos , Lactente , Recém-Nascido , Quênia/epidemiologia , Masculino , Metanálise como Assunto , Fatores de Risco , Índice de Gravidade de Doença
9.
PLoS Genet ; 9(5): e1003509, 2013 May.
Artigo em Inglês | MEDLINE | ID: mdl-23717212

RESUMO

Combining data from genome-wide association studies (GWAS) conducted at different locations, using genotype imputation and fixed-effects meta-analysis, has been a powerful approach for dissecting complex disease genetics in populations of European ancestry. Here we investigate the feasibility of applying the same approach in Africa, where genetic diversity, both within and between populations, is far more extensive. We analyse genome-wide data from approximately 5,000 individuals with severe malaria and 7,000 population controls from three different locations in Africa. Our results show that the standard approach is well powered to detect known malaria susceptibility loci when sample sizes are large, and that modern methods for association analysis can control the potential confounding effects of population structure. We show that pattern of association around the haemoglobin S allele differs substantially across populations due to differences in haplotype structure. Motivated by these observations we consider new approaches to association analysis that might prove valuable for multicentre GWAS in Africa: we relax the assumptions of SNP-based fixed effect analysis; we apply Bayesian approaches to allow for heterogeneity in the effect of an allele on risk across studies; and we introduce a region-based test to allow for heterogeneity in the location of causal alleles.


Assuntos
População Negra/genética , Estudo de Associação Genômica Ampla , Hemoglobina Falciforme/genética , Malária/genética , África , Teorema de Bayes , Mapeamento Cromossômico , Heterogeneidade Genética , Predisposição Genética para Doença , Variação Genética , Genética Populacional , Genoma Humano , Haplótipos , Humanos , Desequilíbrio de Ligação , Malária/epidemiologia , Malária/patologia , Polimorfismo de Nucleotídeo Único
10.
Malar J ; 14: 333, 2015 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-26314886

RESUMO

BACKGROUND: Many studies report associations between human genetic factors and immunity to malaria but few have been reliably replicated. These studies are usually country-specific, use small sample sizes and are not directly comparable due to differences in methodologies. This study brings together samples and data collected from multiple sites across Africa and Asia to use standardized methods to look for consistent genetic effects on anti-malarial antibody levels. METHODS: Sera, DNA samples and clinical data were collected from 13,299 individuals from ten sites in Senegal, Mali, Burkina Faso, Sudan, Kenya, Tanzania, and Sri Lanka using standardized methods. DNA was extracted and typed for 202 Single Nucleotide Polymorphisms with known associations to malaria or antibody production, and antibody levels to four clinical grade malarial antigens [AMA1, MSP1, MSP2, and (NANP)4] plus total IgE were measured by ELISA techniques. Regression models were used to investigate the associations of clinical and genetic factors with antibody levels. RESULTS: Malaria infection increased levels of antibodies to malaria antigens and, as expected, stable predictors of anti-malarial antibody levels included age, seasonality, location, and ethnicity. Correlations between antibodies to blood-stage antigens AMA1, MSP1 and MSP2 were higher between themselves than with antibodies to the (NANP)4 epitope of the pre-erythrocytic circumsporozoite protein, while there was little or no correlation with total IgE levels. Individuals with sickle cell trait had significantly lower antibody levels to all blood-stage antigens, and recessive homozygotes for CD36 (rs321198) had significantly lower anti-malarial antibody levels to MSP2. CONCLUSION: Although the most significant finding with a consistent effect across sites was for sickle cell trait, its effect is likely to be via reducing a microscopically positive parasitaemia rather than directly on antibody levels. However, this study does demonstrate a framework for the feasibility of combining data from sites with heterogeneous malaria transmission levels across Africa and Asia with which to explore genetic effects on anti-malarial immunity.


Assuntos
Anticorpos Antiprotozoários/imunologia , Malária/epidemiologia , Malária/genética , Malária/imunologia , Adolescente , Adulto , África Subsaariana/epidemiologia , Anticorpos Antiprotozoários/sangue , Criança , Pré-Escolar , Feminino , Hemoglobina Falciforme/genética , Humanos , Lactente , Recém-Nascido , Modelos Lineares , Masculino , Sri Lanka/epidemiologia , Adulto Jovem
11.
BMC Med ; 12: 65, 2014 Apr 22.
Artigo em Inglês | MEDLINE | ID: mdl-24755265

RESUMO

BACKGROUND: Sickle cell disease (SCD) is common in many parts of sub-Saharan Africa (SSA), where it is associated with high early mortality. In the absence of newborn screening, most deaths among children with SCD go unrecognized and unrecorded. As a result, SCD does not receive the attention it deserves as a leading cause of death among children in SSA. In the current study, we explored the potential utility of verbal autopsy (VA) as a tool for attributing underlying cause of death (COD) in children to SCD. METHODS: We used the 2007 WHO Sample Vital Registration with Verbal Autopsy (SAVVY) VA tool to determine COD among child residents of the Kilifi Health and Demographic Surveillance System (KHDSS), Kenya, who died between January 2008 and April 2011. VAs were coded both by physician review (physician coded verbal autopsy, PCVA) using COD categories based on the WHO International Classification of Diseases 10th Edition (ICD-10) and by using the InterVA-4 probabilistic model after extracting data according to the 2012 WHO VA standard. Both of these methods were validated against one of two gold standards: hospital ICD-10 physician-assigned COD for children who died in Kilifi District Hospital (KDH) and, where available, laboratory confirmed SCD status for those who died in the community. RESULTS: Overall, 6% and 5% of deaths were attributed to SCD on the basis of PCVA and the InterVA-4 model, respectively. Of the total deaths, 22% occurred in hospital, where the agreement coefficient (AC1) for SCD between PCVA and hospital physician diagnosis was 95.5%, and agreement between InterVA-4 and hospital physician diagnosis was 96.9%. Confirmatory laboratory evidence of SCD status was available for 15% of deaths, in which the AC1 against PCVA was 87.5%. CONCLUSIONS: Other recent studies and provisional data from this study, outlining the importance of SCD as a cause of death in children in many parts of the developing world, contributed to the inclusion of specific SCD questions in the 2012 version of the WHO VA instruments, and a specific code for SCD has now been included in the WHO and InterVA-4 COD listings. With these modifications, VA may provide a useful approach to quantifying the contribution of SCD to childhood mortality in rural African communities. Further studies will be needed to evaluate the generalizability of our findings beyond our local context.


Assuntos
Anemia Falciforme/mortalidade , Autopsia , Prontuários Médicos/estatística & dados numéricos , África Subsaariana/epidemiologia , Causas de Morte , Criança , Feminino , Humanos , Recém-Nascido , Classificação Internacional de Doenças , Quênia/epidemiologia , Masculino , Modelos Estatísticos , População Rural
13.
Pan Afr Med J ; 46: 60, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-38223876

RESUMO

Introduction: accreditation is the most effective approach to ensure the quality of services. Laboratory performance can be evaluated using the World Health Organization (WHO)-SLIPTA checklist, which checks a laboratory´s compliance with ISO 15189 on a five-star score scale and improved using the SLMTA approach. Compliance is assessed by an external body and can result in accreditation. In this paper, we describe the steps taken by the Kenya Medical Research Institute (KEMRI) HIV Laboratory, Alupe, a resource-limited public entity, towards accreditation, and discuss the lessons learned. Methods: the laboratory adopted a SLMTA-SLIPTA approach that included targeted mentorship, on-site workshops, and training. Mentorship-based interventions were used to establish a robust quality management system. Targeted mentorship, on-site workshops, and training were conducted between September 2015 and July 2016. Audits used the SLIPTA checklist to detect gaps in 12 quality system essentials. Performance indicators including turnaround time, external quality assurance, sample rejection rates, and corrective actions were tracked. An external assessment by the national accreditation body was conducted between September 2016 and November 2016. Results: training and mentorship-based interventions were successfully conducted. Quality management systems aligned with ISO 15189 were established. Baseline, midterm, and exit audits yielded scores of 47%, 75%, and 94% respectively. Early infant diagnosis external quality assurance scores were 100% in 2014-2016, while average viral load scores were at 60%, 70% and 90% during the same period. Turnaround time from September 2015 surpassed the 80% target. Accreditation was awarded in March 2017. Conclusion: the SLMTA-SLIPTA approach is suitable for quality improvement in resource-limited laboratories.


Assuntos
Infecções por HIV , Laboratórios , Humanos , Controle de Qualidade , Quênia , Melhoria de Qualidade , Ciência da Implementação , Acreditação , Infecções por HIV/diagnóstico
14.
BMJ Open ; 13(7): e068260, 2023 07 31.
Artigo em Inglês | MEDLINE | ID: mdl-37524553

RESUMO

BACKGROUND: Acute kidney injury (AKI) has in the past been considered a rare complication of malaria in children living in high-transmission settings. More recently, however, a growing number of paediatric case series of AKI in severe malaria studies in African children have been published (Artesunate vs Quinine in the Treatment of Severe P. falciparum Malaria in African children and Fluids Expansion as Supportive Therapy trials). The Paracetamol for Acute Renal Injury in Severe Malaria Trial (PARIST) therefore, aims to assess feasibility, safety and determine the effective dose of paracetamol, which attenuates nephrotoxicity of haemoproteins, red-cell free haemoglobin and myoglobin in children with haemoglobinuric severe malaria. METHODS: PARIST is a phase I/II unblinded randomised controlled trial of 40 children aged >6 months and <12 years admitted with confirmed haemoglobinuric severe malaria (blackwater fever), a positive blood smear for P. falciparum malaria and either serum creatinine (Cr) increase by ≥0.3 mg/dL within 48 hours or to ≥1.5 times baseline and elevated blood urea nitrogen (BUN) >20 mg/dL. Children will be randomly allocated on a 1:1 basis to paracetamol intervention dose arm (20 mg/kg orally 6-hourly for 48 hours) or to a control arm to receive standard of care for temperature control (ie, tepid sponging for 30 min if fever persists give rescue treatment). Primary outcome is renal recovery at 48 hours as indicated by stoppage of progression and decrease of Cr level below baseline, BUN (<20 mg/dL). Data analysis will be on the intention-to-treat principle and a per-protocol basis.Results from this phase I/II clinical trial will provide preliminary effectiveness data of this highly potential treatment for AKI in paediatric malaria (in particular for haemoglobinuric severe malaria) for a larger phase III trial. ETHICS AND DISSEMINATION: Ethical and regulatory approvals have been granted by the Mbale Hospital Institutional Ethics Review Committee (MRRH-REC OUT 002/2019), Uganda National Council of Science and Technology (UNCST-HS965ES) and the National drug Authority (NDA-CTC 0166/2021). We will be disseminating results through journals, conferences and policy briefs to policy makers and primary care providers. TRIAL REGISTRATION NUMBER: ISRCTN84974248.


Assuntos
Injúria Renal Aguda , Malária Falciparum , Malária , Humanos , Criança , Acetaminofen/uso terapêutico , Estudos de Viabilidade , Uganda , Malária/tratamento farmacológico , Malária Falciparum/complicações , Malária Falciparum/tratamento farmacológico , Injúria Renal Aguda/tratamento farmacológico , Injúria Renal Aguda/complicações , Resultado do Tratamento , Ensaios Clínicos Controlados Aleatórios como Assunto , Ensaios Clínicos Fase I como Assunto , Ensaios Clínicos Fase II como Assunto
15.
Lancet ; 378(9799): 1316-23, 2011 Oct 08.
Artigo em Inglês | MEDLINE | ID: mdl-21903251

RESUMO

BACKGROUND: Many investigators have suggested that malaria infection predisposes individuals to bacteraemia. We tested this hypothesis with mendelian randomisation studies of children with the malaria-protective phenotype of sickle-cell trait (HbAS). METHODS: This study was done in a defined area around Kilifi District Hospital, Kilifi, Kenya. We did a matched case-control study to identify risk factors for invasive bacterial disease, in which cases were children aged 3 months to 13 years who were admitted to hospital with bacteraemia between Sept 16, 1999, and July 31, 2002. We aimed to match two controls, by age, sex, location, and time of recruitment, for every case. We then did a longitudinal case-control study to assess the relation between HbAS and invasive bacterial disease as malaria incidence decreased. Cases were children aged 0-13 years who were admitted to hospital with bacteraemia between Jan 1, 1999, and Dec 31, 2007. Controls were born in the study area between Jan 1, 2006, and June 23, 2009. Finally, we modelled the annual incidence of bacteraemia against the community prevalence of malaria during 9 years with Poisson regression. RESULTS: In the matched case-control study, we recruited 292 cases-we recruited two controls for 236, and one for the remaining 56. Sickle-cell disease, HIV, leucocyte haemozoin pigment, and undernutrition were positively associated with bacteraemia and HbAS was strongly negatively associated with bacteraemia (odds ratio 0·36; 95% CI 0·20-0·65). In the longitudinal case-control study, we assessed data from 1454 cases and 10,749 controls. During the study period, the incidence of admission to hospital with malaria per 1000 child-years decreased from 28·5 to 3·45, with a reduction in protection afforded by HbAS against bacteraemia occurring in parallel (p=0·0008). The incidence of hospital admissions for bacteraemia per 1000 child-years also decreased from 2·59 to 1·45. The bacteraemia incidence rate ratio associated with malaria parasitaemia was 6·69 (95% CI 1·31-34·3) and, at a community parasite prevalence of 29% in 1999, 62% (8·2-91) of bacteraemia cases were attributable to malaria. INTERPRETATION: Malaria infection strongly predisposes individuals to bacteraemia and can account for more than half of all cases of bacteraemia in malaria-endemic areas. Interventions to control malaria will have a major additional benefit by reducing the burden of invasive bacterial disease. FUNDING: Wellcome Trust.


Assuntos
Bacteriemia/epidemiologia , Malária Falciparum/epidemiologia , Adolescente , Bacteriemia/microbiologia , Estudos de Casos e Controles , Criança , Transtornos da Nutrição Infantil/epidemiologia , Pré-Escolar , Infecções por HIV/epidemiologia , Hemeproteínas/análise , Humanos , Incidência , Lactente , Quênia/epidemiologia , Estudos Longitudinais , Admissão do Paciente/estatística & dados numéricos , Vigilância da População , Fatores de Risco , Traço Falciforme/epidemiologia
16.
Blood ; 116(10): 1663-8, 2010 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-20530796

RESUMO

Although malaria is widely considered a major cause of death in young children born with sickle cell anemia (SCA) in sub-Saharan Africa, this is poorly quantified. We attempted to investigate this question through 4 large case-control analyses involving 7164 children living on the coast of Kenya. SCA was associated with an increased risk of admission to hospital both with nonmalaria diseases in general (odds ratio [OR] = 4.17; 95% confidence interval [CI], 1.95-8.92; P < .001) and with invasive bacterial diseases in particular (OR = 8.73; 95% CI, 4.51-16.89; P < .001). We found no evidence for a strongly increased risk of either uncomplicated malaria (OR = 0.43; 95% CI, 0.09-2.10; P = .30) or malaria complicated by a range of well-described clinical features of severity (OR = 0.80; 95% CI, 0.25-2.51; P = .70) overall; nevertheless, mortality was considerably higher among SCA than non-SCA children hospitalized with malaria. Our findings highlight both the central role that malaria plays in the high early mortality seen in African children with SCA and the urgent need for better quantitative data. Meanwhile, our study confirms the importance of providing all children living with SCA in malaria-endemic areas with effective prophylaxis.


Assuntos
Anemia Falciforme/mortalidade , Malária Falciparum/mortalidade , Admissão do Paciente/estatística & dados numéricos , Anemia Falciforme/complicações , Anemia Falciforme/genética , Estudos de Casos e Controles , Pré-Escolar , Feminino , Genótipo , Hemoglobina Falciforme/genética , Humanos , Lactente , Quênia/epidemiologia , Malária Falciparum/complicações , Masculino , Razão de Chances , Fatores de Risco , Taxa de Sobrevida
17.
Trop Doct ; 52(1): 61-67, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34939462

RESUMO

Our study aimed at determining clinical factors associated with prolonged hospitalisation and death among children admitted with blackwater fever (BWF). We analysed 920 eligible records for the period January - December 2018 from Mbale and Soroti Regional Referral Hospitals in Eastern Uganda. The median hospitalisation was 3 (IQR: 2-5 days) days. Prolonged hospitalisation was in 251/920 (27.3%). Clinical features independently associated with prolonged hospitalisation included abdominal tenderness, body pain and mild fever. 29/920 (3.2%) died, of these 20 (69.0%) within 48 h of admission. Features of severity associated with mortality were noisy or interrupted breathing, tachypnoea, chest pain, convulsions, delayed capillary refill time (≥3 s), severe pallor, high fever (>38.5°C), altered level of consciousness, prostration and acidotic breathing.


Assuntos
Febre Hemoglobinúrica , Criança , Febre , Hospitalização , Hospitais , Humanos , Uganda/epidemiologia
18.
BMJ Open ; 12(7): e059875, 2022 07 06.
Artigo em Inglês | MEDLINE | ID: mdl-35793920

RESUMO

INTRODUCTION: Blackwater fever (BWF), a complication of malaria, has in the past been considered as a rare complication of malaria in children living in high transmission settings. More recently, however, a growing number of paediatric clusters of BWF cases have been reported predominantly in sub-Saharan Africa (SSA). The aim of this study is to map evidence on BWF among children in SSA from 1 January 1960 to 31 December 2021. METHODS AND ANALYSIS: This review will be guided by Arksey and O' Malley's methodological framework for scoping reviews with methodological refinements by Levac et al and will comply with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews' guidelines. Five electronic databases (MEDLINE via PubMed, Embase, the Cochrane Library, the Cumulative Index to Nursing and Allied Health Literature (CINAHL) and PsycINFO) will be systematically searched using predefined keywords. In addition, reference lists of included articles will be searched. Our multidisciplinary team has formulated search strategies and two reviewers will independently complete study eligibility screening, final selection and data extraction. A third reviewer will adjudicate the final decision on disputed articles. Bibliographic data and abstract content will be collected and analysed using a data-charting tool developed iteratively by the research team. ETHICS AND DISSEMINATION: This scoping review being a secondary analysis does not require ethics approval. We anticipate results of this review will broaden understanding of paediatric BWF in SSA and identify its research gaps in SSA. We will be disseminating results through journals and conferences targeting primary care providers.


Assuntos
Febre Hemoglobinúrica , África Subsaariana/epidemiologia , Criança , Humanos , Programas de Rastreamento , Revisões Sistemáticas como Assunto
19.
Glob Health Res Policy ; 7(1): 11, 2022 04 28.
Artigo em Inglês | MEDLINE | ID: mdl-35478077

RESUMO

BACKGROUND: Virtual global health partnership initiatives (VGHPIs) evolved rapidly during the COVID-19 pandemic to ensure partnership continuity. However the current landscape for VGHPI use and preference is unknown. This study aimed to increase understanding of GH partners' perspectives on VGHPIs. METHODS: From 15 October to 30 November 2020, An online, international survey was conducted using snowball sampling to document pandemic-related changes in partnership activities, preferences for VGHPIs, and perceived acceptability and barriers. The survey underwent iterative development within a diverse author group, representing academic and clinical institutions, and the non-profit sector. Participants from their professional global health networks were invited, including focal points for global health partnerships while excluding trainees and respondents from the European Economic Area. Analysis stratified responses by country income classification and partnership type. Authors used descriptive statistics to characterize responses, defining statistical significance as α = 0.05. RESULTS: A total of 128 respondents described 219 partnerships. 152/219 (69%) partnerships were transnational, 157/219 (72%) were of > 5 years duration, and 127/219 (60%) included bidirectional site visits. High-income country (HIC) partners sent significantly more learners to low- to middle-income country (LMIC) partner sites (p < 0.01). Participants commented on pandemic-related disruptions affecting 217/219 (99%) partnerships; 195/217 (90%) were disruption to activities; 122/217 (56%) to communication; 73/217 (34%) to access to professional support; and 72/217 (33%) to funding. Respondents indicated that VGHPIs would be important to 206/219 (94%) of their partnerships moving forward. There were overall differences in resource availability, technological capacity, and VGHPI preferences between LMIC and HIC respondents, with a statistically significant difference in VGHPI acceptability (p < 0.001). There was no significant difference between groups regarding VGHPIs' perceived barriers. CONCLUSIONS: The pandemic disrupted essential partnership elements, compounding differences between LMIC and HIC partners in their resources and preferences for partnership activities. VGHPIs have the potential to bridge new and existing gaps and maximize gains, bi-directionality, and equity in partnerships during and after COVID-19.


Assuntos
COVID-19 , Saúde Global , COVID-19/epidemiologia , COVID-19/prevenção & controle , Estudos Transversais , Humanos , Cooperação Internacional , Pandemias
20.
Elife ; 112022 07 22.
Artigo em Inglês | MEDLINE | ID: mdl-35866869

RESUMO

Invasive bacterial disease is a major cause of morbidity and mortality in African children. Despite being caused by diverse pathogens, children with sepsis are clinically indistinguishable from one another. In spite of this, most genetic susceptibility loci for invasive infection that have been discovered to date are pathogen specific and are not therefore suggestive of a shared genetic architecture of bacterial sepsis. Here, we utilise probabilistic diagnostic models to identify children with a high probability of invasive bacterial disease among critically unwell Kenyan children with Plasmodium falciparum parasitaemia. We construct a joint dataset including 1445 bacteraemia cases and 1143 severe malaria cases, and population controls, among critically unwell Kenyan children that have previously been genotyped for human genetic variation. Using these data, we perform a cross-trait genome-wide association study of invasive bacterial infection, weighting cases according to their probability of bacterial disease. In doing so, we identify and validate a novel risk locus for invasive infection secondary to multiple bacterial pathogens, that has no apparent effect on malaria risk. The locus identified modifies splicing of BIRC6 in stimulated monocytes, implicating regulation of apoptosis and autophagy in the pathogenesis of sepsis in Kenyan children.


Bacterial infections are a major cause of severe illness and death in African children. Understanding which children are at risk of life-threatening infection and why, is key to designing new tools to help protect them. Some risk is likely inherited, but scientists do not know which genes are responsible. Genome-wide association studies (GWAS) may be one way to identify bacterial infection risk genes. GWAS look for genetic differences associated with a particular disease. But previous GWAS studies have failed to find genes linked with bacterial infections in African children because they were too small. Malaria is another frequent cause of life-threatening illness in African children. It can be hard for clinicians to determine if a child's illness is caused by malaria, a bacterial infection, or both. Many children in Africa have malaria parasites in their blood, but they do not always cause disease. Most children with suspected severe malaria are treated with antibiotics in case of bacterial infection. Clinicians may then conduct further testing to determine the illness's actual cause. Scientists may be able to use this data on children with suspected malaria to study bacterial infections. Gilchrist et al. show that children with an unusual alteration in the BIRC6 gene are at increased risk of bacterial infections. In the experiments, Gilchrist et al. used computer modeling to identify a subset of children with likely bacterial infections among 2,200 children admitted to a hospital in Kenya with a high fever and malaria parasites. By combining information on this subset of children with data on children with confirmed bacterial infections and healthy children, Gilchrist created a sample of 5,400 children for a GWAS. The analyses found that children with a variation in the BIRC6 gene on chromosome 2 had a higher risk of bacterial infections. This genetic change is linked with the production of a modified form of BIRC6 in infection-fighting immune cells called monocytes. More studies will help scientists understand how this change might contribute to severe bacterial infections. Learning more may help scientists develop new treatment strategies and identify children most at risk.


Assuntos
Bacteriemia , Infecções Bacterianas , Malária , Bacteriemia/microbiologia , Criança , Estudo de Associação Genômica Ampla , Humanos , Proteínas Inibidoras de Apoptose , Quênia/epidemiologia , Malária/complicações , Malária/epidemiologia
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