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1.
Genet Res (Camb) ; 2022: 6686406, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35291755

RESUMO

Background: One major issue that has set back the gains of the numerous malaria control interventions that national malaria control programs have implemented is asymptomatic malaria. Certain host genetic factors are known to influence symptomatic malaria; however, not much is known about how host genetics influences the acquisition of asymptomatic malaria. Methods: Genomic DNA was extracted from whole blood collected from 60 symptomatic and 149 nonfebrile (asymptomatic, N = 109, and uninfected, N = 40) volunteers aged between 2 and 69 years from a high (Obom) and a low (Asutsuare) malaria transmission setting in Southern Ghana. Restriction fragment length polymorphism (RFLP) was used to determine polymorphisms at the MBL2 54, TNF-α 308, NOS2 954, and G6PD 202/376 gene loci. Results: Polymorphisms at the MBL2 54 and TNF-α 308 loci were significantly different amongst the three categories of volunteers in both Asutsuare (p = 0.006) and Obom (p=0.05). In Asutsuare, a low malaria transmission area, the allele G has significantly higher odds (3.15) of supporting asymptomatic malaria as against symptomatic malaria. There were significantly higher odds of TNF-α genotype GA being associated with symptomatic malaria as against asymptomatic malaria in both sites, Obom (p=0.027) and Asutsuare (p=0.027). The allele B of the G6PD gene was more prevalent in symptomatic rather than asymptomatic parasite-infected individuals in both Obom (p=0.001) and Asutsuare (p=0.003). Conclusion: Individuals in Southern Ghana carrying the TNF-α 308 GA genotype are more likely to exhibit symptoms of malaria when infected with the malaria parasite as opposed to harboring an asymptomatic infection. Also, the B allele of the G6PD gene is likely to prevent a P. falciparum-infected person from exhibiting symptoms and thereby promote asymptomatic parasite carriage.


Assuntos
Malária Falciparum , Malária , Lectina de Ligação a Manose , Adolescente , Adulto , Idoso , Antígenos de Protozoários/genética , Criança , Pré-Escolar , Gana/epidemiologia , Humanos , Malária/epidemiologia , Malária/genética , Malária Falciparum/diagnóstico , Malária Falciparum/parasitologia , Pessoa de Meia-Idade , Óxido Nítrico Sintase Tipo II , Plasmodium falciparum/genética , Proteínas de Protozoários/genética , Fator de Necrose Tumoral alfa/genética , Adulto Jovem
2.
BMC Public Health ; 22(1): 1899, 2022 10 12.
Artigo em Inglês | MEDLINE | ID: mdl-36224589

RESUMO

BACKGROUND: Vaccine-preventable diseases (VPDs) persist globally with a disproportionately high burden in Low and Middle-Income Countries (LMICs). Although this might be partly due to the failure to sustain vaccination coverage above 90% in some WHO regions, a more nuanced understanding of VPD transmission beyond vaccination coverage may unveil other important factors in VPD transmission and control. This study identified VPDs hotspots and explored their relationships with ecology, urbanicity and land-use variations (Artisanal and Small-scale Gold Mining (ASGM) activities) in Ghana. METHODS: District-level disease count data from 2010 to 2014 from the Ghana Health Service (GHS) and population data from the Ghana Population and Housing Census (PHC) were used to determine clustering patterns of six VPDs (Measles, Meningitis, Mumps, Otitis media, Pneumonia and Tetanus). Spatial and space-time cluster analyses were implemented in SaTScan using the discrete Poisson model. P-values were estimated using a combination of sequential Monte Carlo, standard Monte Carlo, and Gumbel approximations. RESULTS: The study found a preponderance for VPD hotspots in the northern parts of Ghana and northernmost ecological zones (Sudan Savannah and Guinea Savannah). Incidence of meningitis was higher in the Sudan Savannah ecological zone relative to: Tropical Rain Forest (p = 0.001); Semi Deciduous Forest (p < 0.0001); Transitional Zone (p < 0.0001); Coastal Savannah (p < 0.0001) and Guinea Savannah (p = 0.033). Except for mumps, which recorded a higher incidence in urban districts (p = 0.045), incidence of the other five VPDs did not differ across the urban-rural divide. Whereas spatial analysis suggested that some VPD hotspots (tetanus and otitis media) occur more frequently in mining districts in the southern part of the country, a Mann-Whitney U test revealed a higher incidence of meningitis in non-mining districts (p = 0.019). Pneumonia and meningitis recorded the highest (722.8 per 100,000) and least (0.8 per 100,000) incidence rates respectively during the study period. CONCLUSION: This study shows a preponderance of VPD hotspots in the northern parts of Ghana and in semi-arid ecoclimates. The relationship between ASGM activities and VPD transmission in Ghana remains blurred and requires further studies with better spatial resolution to clarify.


Assuntos
Caxumba , Tétano , Doenças Preveníveis por Vacina , Gana/epidemiologia , Ouro , Humanos , Conglomerados Espaço-Temporais , Toxoide Tetânico
3.
Curr HIV/AIDS Rep ; 18(2): 87-97, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33606196

RESUMO

PURPOSE OF REVIEW: Sub-Saharan Africa (SSA) is disproportionately burdened by the twin epidemics of food insecurity and HIV infection, and protein-calorie undernutrition is common among persons with HIV (PWH) initiating antiretroviral therapy (ART) in the region. In this review, we discuss the intersection of HIV infection and undernutrition, health outcomes among undernourished PWH starting ART, and the demonstrated and potential benefits of therapeutic interventions such as micro/macronutrient supplementation and pharmacological agents. RECENT FINDINGS: A low body mass index (BMI), used as a general indicator of poor nutrition in most studies, is associated with impaired immune recovery and increased mortality in the early ART period. The increased risk of mortality is multifactorial, and contributors include undernutrition-related immune system dysfunction, increased susceptibility to opportunistic infections, and metabolic and cardiovascular dysregulation. Clinical trials of micro/macronutrient supplementary feeding, appetite stimulants (hormones and anabolic agents), and recombinant adipokines have shown a benefit for weight gain and metabolic health, but there are few data on mortality or immune recovery. A substantial proportion of PWH in SSA are undernourished, and undernutrition contributes to an increased risk of mortality and other adverse health outcomes. To date, there have been few prospective trials of nutritional supplementation and/or pharmacologic therapy among undernourished PWH in SSA, though findings from other settings suggest a potential benefit in this population.


Assuntos
Infecções por HIV , Desnutrição , África Subsaariana/epidemiologia , Infecções por HIV/complicações , Infecções por HIV/tratamento farmacológico , Humanos , Desnutrição/complicações , Avaliação de Resultados em Cuidados de Saúde , Estudos Prospectivos
4.
Malar J ; 19(1): 64, 2020 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-32041620

RESUMO

BACKGROUND: Asymptomatic carriage of Plasmodium falciparum is widespread in adults and children living in malaria-endemic countries. This study identified the prevalence of malaria parasites and the corresponding levels of naturally acquired anti-parasite antibody levels in afebrile adults living in two communities in the Greater Accra Region of Ghana. METHODS: Two cross-sectional studies conducted in January and February 2016 and repeated in July and August 2016 recruited subjects aged between 6 and 75 years from high parasite prevalence (Obom) and low parasite prevalence (Asutsuare) communities. Whole blood (5 ml) was collected from each volunteer, plasma was aliquoted and frozen until needed. An aliquot (10 µl) of the blood was used to prepare thick and thin blood smears, 100 µl was preserved in Trizol and the rest was separated into plasma and blood cells and each stored at - 20 °C until needed. Anti-MSP3 and Pfs230 antibody levels were measured using ELISA. RESULTS: Asexual parasite and gametocyte prevalence were higher in Obom than Asutsuare. Antibody (IgG, IgG1, IgG3, IgM) responses against the asexual parasite antigen MSP3 and gametocyte antigen Pfs230 were higher in Obom during the course of the study except for IgM responses against Pfs230, which was higher in Asutsuare than in Obom during the rainy season. Antibody responses in Asutsuare were more significantly associated with age than the responses measured in Obom. CONCLUSION: The pattern of antibody responses measured in people living in the high and low malaria transmission setting was similar. All antibody responses measured against the asexual antigen MSP3 increased, however, IgG and IgG1 responses against gametocyte antigen Pfs230 decreased in moving from the dry to the peak season in both sites. Whilst asexual and gametocyte prevalence was similar between the seasons in the low transmission setting, in the high transmission setting asexual parasite prevalence increased but gametocyte prevalence decreased in the rainy season relative to the dry season.


Assuntos
Portador Sadio/epidemiologia , Malária Falciparum/epidemiologia , Plasmodium falciparum/imunologia , Adolescente , Adulto , Fatores Etários , Idoso , Anticorpos Antiprotozoários/sangue , Infecções Assintomáticas/epidemiologia , Portador Sadio/imunologia , Portador Sadio/parasitologia , Criança , Ensaio de Imunoadsorção Enzimática , Gana/epidemiologia , Humanos , Imunoglobulina G/sangue , Imunoglobulina M/sangue , Modelos Lineares , Malária Falciparum/imunologia , Malária Falciparum/parasitologia , Pessoa de Meia-Idade , Plasmodium falciparum/crescimento & desenvolvimento , Prevalência , RNA de Protozoário/sangue , Chuva , Reação em Cadeia da Polimerase em Tempo Real , Estações do Ano , Adulto Jovem
5.
Trop Med Int Health ; 21(12): 1592-1601, 2016 12.
Artigo em Inglês | MEDLINE | ID: mdl-27671831

RESUMO

BACKGROUND: Malaria elicits inflammatory responses, which, if not well regulated, may exert detrimental effects. When activated, triggering receptor expressed on myeloid cells 1 (TREM-1) enhances inflammatory responses by increasing secretion of IL-8 and other Th1 cytokines. In contrast, TREM-like transcript 1 (TREML-1) promotes anti-inflammatory responses by binding to TREM-1 ligands and competing with TREM-1, thus antagonizing TREM-1 activation to reduce inflammation. Endothelial protein C receptor (EPCR) also mediates anti-inflammatory responses by activating endothelial protein C (PC). Upon microbial stimulation, soluble forms of TREM-1 (sTREM-1) and soluble EPCR (sEPCR) are released. Their plasma levels reflect the degree of inflammation and the severity of infection. METHODS: In a cross-sectional study comparing patients with severe with uncomplicated malaria, sTREM-1, soluble TREML-1 (sTREML-1) and sEPCR plasma levels as well as plasma levels of sEPCR derived from convalescent patients were quantified. Samples were collected on admittance of paediatric patients infected with Plasmodium falciparum to hospitals in Accra, Ghana. Distinct genetic regions of the genes encoding TREM-1, EPCR, interleukin (IL)-8 and IL-18 encompassing known genetic polymorphisms that influence plasma levels underwent DNA sequencing. RESULTS: Higher sTREM-1 levels were observed among children suffering from severe malaria compared to those with uncomplicated malaria (P = 0.049). Low TREM-1 to TREML-1 ratios were associated with uncomplicated malaria (P = 0.033). The TREM1 rs2234237T variant causing the amino acid exchange Thr25Ser, which has been associated with higher TREM-1 plasma levels, was significantly more frequent among patients with severe malaria than in those with uncomplicated malaria (P = 0.036). Low levels of sEPCR were observed in severe and uncomplicated malaria, while variant genotypes of IL8, IL18 and EPCR did not show any association. CONCLUSION: Higher plasma levels of sTREM-1 alone or relative to sTREML-1 during malaria predispose to the phenotype of severe malaria. Carriage of the TREM1 rs2234237T allele appears to be a risk factor for the development of severe malaria.


Assuntos
Alelos , Citocinas/genética , Genótipo , Malária Falciparum/genética , Glicoproteínas de Membrana/genética , Fenótipo , Polimorfismo Genético , Receptores Imunológicos/genética , Antígenos CD/sangue , Criança , Pré-Escolar , Citocinas/sangue , Receptor de Proteína C Endotelial , Feminino , Gana , Humanos , Lactente , Interleucina-18/genética , Interleucina-8/genética , Masculino , Glicoproteínas de Membrana/sangue , Receptores de Superfície Celular/sangue , Receptores Imunológicos/sangue , Análise de Sequência de DNA , Índice de Gravidade de Doença , Solubilidade , Receptor Gatilho 1 Expresso em Células Mieloides
6.
Malar J ; 15: 89, 2016 Feb 16.
Artigo em Inglês | MEDLINE | ID: mdl-26879905

RESUMO

BACKGROUND: Cryptolepine (CPE) is the major indoloquinoline isolated from the popular West African anti-malarial plant, Cryptolepis sanguinolenta. CPE possesses various pharmacological activities with potent anti-malarial activity against both chloroquine (CQ)-resistant and -sensitive strains. The search for safe and novel anti-malarial agents and combinations to delay resistance development to Plasmodium falciparum directed this work aimed at evaluating the anti-malarial interaction and safety of CPE in combination with some artemisinin derivatives. METHODS: The in vitro SYBR Green I, fluorescent-based, drug sensitivity assay using a fixed ratio method was carried out on the CQ-sensitive plasmodial strain 3D7 to develop isobolograms from three CPE-based combinations with some artemisinin derivatives. CPE and artesunate (ART) combinations were also evaluated using the Rane's test in ICR mice infected with Plasmodium berghei NK-65 strains in a fixed ratio combination (1:1) and fractions of their ED50s in order to determine the experimental ED50 (Zexp) of the co-administered compounds. Isobolograms were constructed to compare the Zexp to the Zadd. RESULTS: CPE exhibited promising synergistic interactions in vitro with ART, artemether and dihydroartemisinin. In vivo, CPE combination with ART again showed synergy as the Zexp was 1.02 ± 0.02, which was significantly less than the Zadd of 8.3 ± 0.31. The haematological, biochemical, organ/body weight ratio and histopathology indices in the rats treated with CPE at all doses (25, 50, 100 mg kg(-1) po) and in combination with ART (4 mg kg(-1)) showed no significant difference compared to the control group. CONCLUSION: The combination of CPE with the artemisinin derivatives were safe in the rodent model and showed a synergistic anti-malarial activity in vivo and in vitro. This study supports the basis for the selection of CPE as a prospective lead compound as the search for new anti-malarial combinations continues.


Assuntos
Antimaláricos/uso terapêutico , Malária/tratamento farmacológico , Animais , Antimaláricos/farmacologia , Artemisininas/farmacologia , Artemisininas/uso terapêutico , Cryptolepis/química , Sinergismo Farmacológico , Quimioterapia Combinada , Alcaloides Indólicos/farmacologia , Alcaloides Indólicos/uso terapêutico , Masculino , Camundongos , Camundongos Endogâmicos ICR , Plasmodium berghei/efeitos dos fármacos , Plasmodium berghei/fisiologia , Quinolinas/farmacologia , Quinolinas/uso terapêutico , Ratos , Ratos Sprague-Dawley
7.
Malar J ; 15: 55, 2016 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-26830334

RESUMO

BACKGROUND: Malaria eradication requires a concerted approach involving all available control tools, and an effective vaccine would complement these efforts. An effective malaria vaccine should be able to induce protective immune responses in a genetically diverse population. Identification of immunodominant T cell epitopes will assist in determining if candidate vaccines will be immunogenic in malaria-endemic areas. This study therefore investigated whether class I-restricted T cell epitopes of two leading malaria vaccine antigens, Plasmodium falciparum circumsporozoite protein (CSP) and apical membrane antigen-1 (AMA1), could recall T cell interferon-γ responses from naturally exposed subjects using ex vivo ELISpot assays. METHODS: Thirty-five subjects aged between 24 and 43 years were recruited from a malaria-endemic urban community of Ghana in 2011, and their peripheral blood mononuclear cells (PBMCs) were tested in ELISpot IFN-γ assays against overlapping 15mer peptide pools spanning the entire CSP and AMA1 antigens, and 9-10mer peptide epitope mixtures that included previously identified and/or predicted human leukocyte antigen (HLA) class 1-restricted epitopes from same two antigens. RESULTS: For CSP, 26 % of subjects responded to at least one of the nine 15mer peptide pools whilst 17 % responded to at least one of the five 9-10mer HLA-restricted epitope mixtures. For AMA1, 63 % of subjects responded to at least one of the 12 AMA1 15mer peptide pools and 51 % responded to at least one of the six 9-10mer HLA-restricted epitope mixtures. Following analysis of data from the two sets of peptide pools, along with bioinformatics predictions of class I-restricted epitopes and the HLA supertypes expressed by a subset of study subjects, peptide pools that may contain epitopes recognized by multiple HLA supertypes were identified. Collectively, these results suggest that natural transmission elicits ELISpot IFN-γ activities to class 1-restricted epitopes that are largely HLA-promiscuous. CONCLUSIONS: These results generally demonstrate that CSP and AMA1 peptides recalled ELISpot IFN-γ responses from naturally exposed individuals and that both CSP and AMA1 contain diverse class 1-restricted epitopes that are HLA-promiscuous and are widely recognized in this population.


Assuntos
Interferon gama/metabolismo , Malária/imunologia , Malária/metabolismo , Plasmodium falciparum/imunologia , Proteínas de Protozoários/imunologia , Adulto , Biologia Computacional , ELISPOT , Feminino , Humanos , Masculino , Adulto Jovem
8.
Malar J ; 14: 20, 2015 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-25604473

RESUMO

BACKGROUND: A malaria vaccine that targets the sporozoite/liver stage parasites could potentially prevent blood stage infection and the associated clinical symptoms. Identification of sporozoite/liver stage antigens is, therefore, crucial for the development of effective vaccines. Cell-traversal protein for ookinetes and sporozoites (CelTOS) is a highly conserved antigen involved in sporozoite motility and hepatocyte invasion and has been shown to induce significant IFN-γ production in PBMCs from radiation-attenuated sporozoite-immunized malaria-naïve individuals. The aim of this study was to ascertain whether such CelTOS-specific recall responses are also induced in individuals with natural exposure to Plasmodium falciparum. METHODS: Ex vivo IFN-γ responses to 15mer overlapping peptide pools covering the entire sequence of CelTOS and five other candidate antigens, CSP, AMA1, MSP1, TRAP and LSA1, were characterized using PBMCs from 35 malaria exposed adults. Responses to four CelTOS peptide pools (CelTp1, CelTp2, CelTp3 and CelTp4), a pool containing peptides from the entire CelTOS antigen (CelTTp), and pools comprised of overlapping peptides from each of the other five malaria antigens were assessed by ex vivo ELISpot assay. A positive IFN-γ response for stimulants was defined by two criteria; a stimulation index of two or greater relative to the unstimulated control, and a difference of 10 or greater in spot forming cells between stimulant and the unstimulated control. RESULTS: Of the 35 volunteers tested, five had positive IFN-γ recall responses against the four different CelTOS pools while four volunteers made responses against the CelTTp pool; six volunteers were, therefore, positive with CelTOS. By contrast, six volunteers responded to AMA1, seven to LSA1, 15 to MSP1 and two volunteers responded against CSP and TRAP. CONCLUSIONS: These results suggest natural malaria transmission induces CelTOS-specific ex vivo IFN-γ in Ghanaian adults and that the frequency of these responses was similar to those of other previously characterized malaria antigens. These findings support the further evaluation of CelTOS as a pre-erythrocytic candidate antigen for inclusion in a potential multi-antigen vaccine.


Assuntos
Antígenos de Protozoários/imunologia , Interferon gama/metabolismo , Leucócitos Mononucleares/imunologia , Plasmodium falciparum/imunologia , Proteínas de Protozoários/imunologia , Esporozoítos/imunologia , Adulto , ELISPOT , Feminino , Gana , Humanos , Masculino
10.
PLoS Negl Trop Dis ; 16(3): e0010115, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-35263327

RESUMO

BACKGROUND: Evidence from recent studies in Schistosoma mansoni-endemic areas show an age-associated immunity that is positively correlated with IgE titres to Schistosoma mansoni-specific tegumental allergen-like protein 1 (SmTAL1). The structural homology between SmTAL1 and the S. haematobium-specific TAL1 (ShTAL1) has been verified, yet it remains unclear whether similar age- and immune-associated trends characterize ShTAL1. This community-based intervention study was conducted to assess whether ShTAL1IgE responses post-treatment with praziquantel (PZQ) might be associated with a reduced risk to re-infection with S. haematobium. METHODOLOGY/PRINCIPAL FINDINGS: This study was conducted at Agona Abodom, Central Region, Ghana, and involved 114 participants aged 6 to 55 years. EDTA blood samples were collected at baseline and 7 weeks after PZQ treatment (Follow-up). Baseline and Follow-up titres of specific IgG1, IgG4, and IgE antibodies to the S. haematobium-specific adult worm antigen (ShAWA), the Sh-specific soluble egg antigen (ShSEA), and the Sh-specific tegumental-allergen-like 1 protein (ShTAL1) in plasma samples were measured using sandwich ELISA. Participants at both time points also provided stool and urine for helminth egg detection by microscopy. Prevalence of S. haematobium at baseline was 22.80%, and decreased to 3.50% at Follow-up. The egg reduction rate (ERR) was 99.87%. Overall plasma levels of ShTAL1-IgE increased 7 weeks post-PZQ treatment, and with increasing age; whiles S. haematobium infection prevalence and intensity decreased. For S. haematobium-infected participants who were egg-negative at Follow-up (N = 23), minimal median levels of ShTAL1-IgE were observed for all age groups prior to treatment, whilst median levels increased considerably among participants aged 12 years and older at Follow-up; and remained minimal among participants aged 11 years or less. In the univariate analysis, being aged 12 years or older implied an increased likelihood for ShTAL1-IgE positivity [12-14 years (cOR = 9.64, 95% CI = 2.09-44.51; p = 0.004); 15+ years (cOR = 14.26, 95% CI = 3.10-65.51; p = 0.001)], and this remained significant after adjusting for confounders [12-14 years (aOR = 22.34, 95% CI = 2.77-180.14; p = 0.004); ≥15 years (aOR = 51.82, 95% CI = 6.44-417.17; p < 0.001)]. Conversely, median ShTAL1-IgG4 titres were hardly detectible at Follow-up. CONCLUSIONS/SIGNIFICANCE: These findings demonstrate that increased IgE levels to ShTAL1 7 weeks after PZQ treatment could be associated with a reduced risk to re-infection, and adds to the large body of evidence suggesting a protective role of the treatment-induced ShTAL1 antigen in schistosomiasis infections. It was also quite clear from this work that apart from being persistently S. haematobium-positive, elevated ShTAL1-IgG4 levels at Follow-up could be indicative of susceptibility to re-infection. These outcomes have important implications in vaccine development, and in shifting the paradigm in mass chemotherapy programmes from a 'one-size-fits-all' approach to more sub-group-/participant-specific strategies in endemic areas.


Assuntos
Anti-Helmínticos , Esquistossomose Urinária , Alérgenos , Animais , Anti-Helmínticos/uso terapêutico , Feminino , Gana/epidemiologia , Humanos , Imunoglobulina E , Imunoglobulina G , Masculino , Praziquantel/uso terapêutico , Reinfecção , Schistosoma haematobium , Schistosoma mansoni , Esquistossomose Urinária/tratamento farmacológico , Esquistossomose Urinária/epidemiologia , Resultado do Tratamento
12.
Hum Vaccin ; 6(1): 12-6, 2010 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-19806020

RESUMO

The quest for an effective vaccine as an additional strategy in the control of malaria and to significantly impact the disease burden has progressed tremendously over the past decade and there is a very high probability that a malaria vaccine will be available for use in the near future. The development and deployment of an effective malaria vaccine faces several challenges and the early engagement of endemic country institutions in the entire process will be beneficial to all. It is very likely that the initial vaccine candidates will have to be improved upon, especially as our understanding of the disease processes improves and the number of potential vaccine antigens increase. This will place greater demands on the currently insufficient capacity for trials. Current strategies for testing and deployment of a malaria vaccine, for example those focusing on risk groups such as infants and children and pregnant women, will also need modifications as efforts are moved towards malaria elimination. Also, a successful malaria vaccine development process will need strengthening of the currently weak regulatory framework in endemic countries to enable them have oversight over clinical trials. The introduction of any malaria vaccine will be confronted by some cultural issues and it is essential to understand how these factors will ultimately affect its utilization. These and other challenges related to the development and deployment of an effective malaria vaccine especially as they concern endemic countries are discussed.


Assuntos
Doenças Endêmicas , Vacinas Antimaláricas/imunologia , Malária/epidemiologia , Malária/prevenção & controle , Pesquisa Translacional Biomédica/organização & administração , Criança , Pré-Escolar , Ensaios Clínicos como Assunto , Aprovação de Drogas , Feminino , Humanos , Lactente , Recém-Nascido , Gravidez
13.
Adv Med Educ Pract ; 11: 473-478, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32753996

RESUMO

The corona virus pandemic undoubtedly demonstrates the growing need for research in medical science. However, with the decline in physician scientists world-wide, innovative ways are needed to engender interest in research among medical students and young doctors to replenish the stock of physician investigators. One way of doing this is to create compulsory and elective projects for them. We describe research internships created for medical students at the Noguchi Memorial Institute for Medical Research to expose them to the rudiments of biomedical research and proposal development. We also describe research internships for doctors waiting for house job postings or keen to do research who needed mentorship. Though the response has been positive, the full impact will be realized with time. The recognition that training should be backed with a supportive environment, mentorship and clear career paths for physician scientists is also mentioned.

14.
J Trop Med ; 2020: 1386587, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32308690

RESUMO

Water bodies such as dams are known to alter the local transmission patterns of a number of infectious diseases, especially those transmitted by insects and other arthropod vectors. The impact of an irrigation dam on submicroscopic asexual parasite carriage in individuals living in a seasonal malaria transmission area of northern Ghana was investigated. A total of 288 archived DNA samples from two cross-sectional surveys in two communities in the Bongo District of Northern Ghana were analysed. Parasite density was determined by light microscopy and PCR, and parasite diversity was assessed by genotyping of the polymorphic Plasmodium falciparum msp2 block-3 region. Submicroscopic parasitaemia was estimated as the proportional difference between positive samples identified by PCR and microscopy. Dry season submicroscopic parasite prevalence was significantly higher (71.0%, p=0.013) at the dam site compared with the nondam site (49.2%). Similarly, wet season submicroscopic parasite prevalence was significantly higher at the dam site (54.5%, p=0.008) compared with the nondam site (33.0%). There was no difference in parasite density between sites in the dry season (p=0.90) and in the wet season (p=0.85). Multiplicity of infection (MOI) based on PCR data was significantly higher at the dam site compared with the nondam site during the dry season (p < 0.0001) but similar between sites during the wet season. MOI at the nondam site was significantly higher in the wet season than in the dry season (2.49, 1.26, p < 0.0001) but similar between seasons at the dam site. Multivariate analysis showed higher odds of carrying submicroscopic parasites at the dam site in both dry season (OR = 7.46, 95% CI = 3.07-18.15) and in wet season (OR = 1.73, 95% CI = 1.04-2.86). The study findings suggest that large water bodies impact year-round carriage of submicroscopic parasites and sustain Plasmodium transmission.

15.
Genes (Basel) ; 10(6)2019 06 07.
Artigo em Inglês | MEDLINE | ID: mdl-31181699

RESUMO

: Background: Diversity in Plasmodium falciparum poses a major threat to malaria control and elimination interventions. This study utilized 12 polymorphic microsatellite (MS) markers and the Msp2 marker to examine diversity, multiplicity of infection (MOI) as well as the population structure of parasites circulating in two sites separated by about 92 km and with varying malaria transmission intensities within the Greater Accra Region of Ghana. METHODS: The diversity and MOI of P. falciparum parasites in 160 non-symptomatic volunteers living in Obom (high malaria transmission intensity) and Asutsuare (low malaria transmission intensity) aged between 8 and 60 years was determined using Msp2 genotyping and microsatellite analysis. RESULTS: The prevalence of asymptomatic P. falciparum carriers as well as the parasite density of infections was significantly higher in Obom than in Asutsuare. Samples from Asutsuare and Obom were 100% and 65% clonal, respectively, by Msp2 genotyping but decreased to 50% and 5%, respectively, when determined by MS analysis. The genetic composition of parasites from Obom and Asutsuare were highly distinct, with parasites from Obom being more diverse than those from Asutsuare. CONCLUSION: Plasmodium falciparum parasites circulating in Obom are genetically more diverse and distinct from those circulating in Asutsuare. The MOI in samples from both Obom and Asutsuare increased when assessed by MS analysis relative to MSP2 genotyping. The TA40 and TA87 loci are useful markers for estimating MOI in high and low parasite prevalence settings.


Assuntos
Antígenos de Protozoários/genética , Genética Populacional , Malária Falciparum/genética , Plasmodium falciparum/genética , Proteínas de Protozoários/genética , Adolescente , Adulto , Criança , Feminino , Variação Genética/genética , Gana/epidemiologia , Heterozigoto , Humanos , Malária Falciparum/epidemiologia , Malária Falciparum/parasitologia , Malária Falciparum/transmissão , Masculino , Repetições de Microssatélites/genética , Pessoa de Meia-Idade , Plasmodium falciparum/patogenicidade , Adulto Jovem
16.
PLoS One ; 13(8): e0202218, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30118498

RESUMO

OBJECTIVE: We assessed the association of mutant allele frequencies of nitric oxide synthase 2 (NOS2) gene at two SNPs (-954 and -1173) with malaria disease severity in children from a malaria endemic area in Southern Ghana. METHOD: Using children recruited at the hospital, assigned into clinical subgroups of uncomplicated and severe malaria and matching with their "healthy control" counterparts, we designed a case control study. Genomic DNA was extracted and genotyping using Restriction Fragment Polymorphism was done. RESULT: A total of 123 malaria cases (91 uncomplicated, 32 severe) and 100 controls were sampled. Their corresponding mean Hbs were 9.6, 9.3 and 11.2g/dl and geometric mean parasite densities of 32097, 193252 and 0 parasites/ml respectively. Variant allele frequencies varied from 0.09 through 0.03 to 0.12 for G-954C and 0.06 through 0.03 to 0.07 for C-1173T in the uncomplicated, severe and healthy control groups respectively. There was a strong linkage disequilibrium between the two alleles (p<0.001). For the -954 position, the odds of developing severe malaria was found to be 2.5 times lower with the carriage of a C allele compared to those without severe malaria (χ2; p< 0.05) though this isn't the case with -1173. CONCLUSION: The carriage of a mutant allele in the -954 NOS2 gene may have a protective effect on malaria among Southern Ghanaian children.


Assuntos
Malária Falciparum/enzimologia , Malária Falciparum/genética , Malária/enzimologia , Malária/genética , Óxido Nítrico Sintase Tipo II/genética , Plasmodium malariae , Estudos de Casos e Controles , Pré-Escolar , Feminino , Frequência do Gene , Gana , Humanos , Lactente , Recém-Nascido , Malária/prevenção & controle , Malária Falciparum/prevenção & controle , Masculino , Polimorfismo de Nucleotídeo Único , Regiões Promotoras Genéticas
18.
PLoS One ; 12(9): e0185303, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28945794

RESUMO

INTRODUCTION: Plasmodium falciparum induced antibodies are key components of anti-malarial immunity in malaria endemic areas, but their antigen targets can be polymorphic. Induction of a high proportion of strain-specific antibodies will limit the recognition of a broad diversity of parasite strains by these responses. There are indications that circulating parasite diversity varies with malaria transmission intensity, and this may affect the specificity of elicited anti-malarial antibodies. This study therefore assessed the effect of varying malaria transmission patterns on the specificity of elicited antibody responses and to identify possible antibody correlates of naturally acquired immunity to malaria in children in an area of Ghana with seasonal malaria transmission. METHODS: This retrospective study utilized plasma samples collected longitudinally at six time points from children aged one to five years. Multiplex assays were used to measure antibody levels against four P. falciparum AMA 1 variants (from the 3D7, FVO, HB3 and CAMP parasite strains) and the 3D7 variant of the EBA 175 region II antigen and the levels compared between symptomatic and asymptomatic children. The relative proportions of cross-reactive and strain-specific antibodies against the four AMA 1 variants per sampling time point were assessed by Bland-Altman plots. The levels of antibodies against allelic AMA1 variants, measured by singleplex and multiplex luminex assays, were also compared. RESULTS: The data show that increased transmission intensity is associated with higher levels of cross-reactive antibody responses, most likely a result of a greater proportion of multiple parasite clone infections during the high transmission period. Anti-AMA1 antibodies were however associated with a history of infection rather than protection in this age group. CONCLUSION: The data contribute to understanding the underlying mechanism of the acquisition of strain-transcending antibody immunity following repeated exposure to diverse parasite strains.


Assuntos
Anticorpos Antiprotozoários/sangue , Malária Falciparum/imunologia , Malária Falciparum/transmissão , Sequência de Aminoácidos , Animais , Especificidade de Anticorpos , Antígenos de Protozoários/genética , Antígenos de Protozoários/imunologia , Criança , Pré-Escolar , Estudos de Coortes , Reações Cruzadas , Feminino , Gana/epidemiologia , Humanos , Imunoensaio/métodos , Lactente , Estudos Longitudinais , Malária Falciparum/epidemiologia , Masculino , Proteínas de Membrana/genética , Proteínas de Membrana/imunologia , Plasmodium falciparum/genética , Plasmodium falciparum/imunologia , Proteínas de Protozoários/genética , Proteínas de Protozoários/imunologia , Estações do Ano
19.
Genet Epigenet ; 8: 7-14, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27279750

RESUMO

Malaria pathogenesis may be influenced by IgE responses and cytokine cross-regulation. Several mutations in the IL-4/STAT6 signaling pathway can alter cytokine cross-regulation and IgE responses during a Plasmodium falciparum malarial infection. This study investigated the relationship between a STAT6 intronic single-nucleotide polymorphism (rs3024974), total IgE, cytokines, and malaria severity in 238 Ghanaian children aged between 0.5 and 13 years. Total IgE and cytokine levels were measured by ELISA, while genotyping was done by polymerase chain reaction-restriction fragment length polymorphism (RFLP). Compared with healthy controls, heterozygosity protected against clinical malaria: uncomplicated malaria (odds ratios [OR] = 0.13, P < 0.001), severe malarial anemia (OR = 0.18, P < 0.001), and cerebral malaria (OR = 0.39, P = 0.022). Levels of total IgE significantly differed among malaria phenotypes (P = 0.044) and rs3024974 genotypes (P = 0.037). Neither cytokine levels nor IL-6/IL-10 ratios were associated with malaria phenotypes or rs3024974 genotypes. This study suggests a role for rs3024974 in malaria pathogenesis and offers further insights into an IL-4/STAT6 pathway mutation in malaria pathogenesis.

20.
Artigo em Inglês | MEDLINE | ID: mdl-26106434

RESUMO

Benign prostatic hyperplasia (BPH) is an enlargement of the prostate. The study aimed at validating the use of freeze-dried Croton membranaceus ethanolic root extract for BPH management. Thirty-three patients were observed before and after 3-month administration of 20 mg t.i.d orally. The International Prostate Symptom Score (IPSS), and the International Index of Erectile Function (IIEF) questionnaires were used. Total/free PSA (tPSA, fPSA), renal, liver function, lipid tests, and ultrasonographic imaging were performed. Thirty (30) patients (66 ± 11 years) completed the study. IPSS results showed 37% had severe, 40% moderate, and 23% mild symptoms before; 57% and 43% had moderate and mild symptoms, respectively, after treatment. IIED of patients' results showed 30% with severe, 40% moderate, 24% mild-moderate, 3% mild, and 3% no erectile dysfunction before treatment and 20% severe, 43% moderate, and 37% mild-moderate dysfunction, after treatment. Quality of life (QoL) improved (P = 0.001). Significant but non-pathological increases in total and indirect bilirubin as well as apolipoprotein A occurred. Mean tPSA reduced from 27.9 ± 19.0 to 16.2 ± 11.8 ng/mL (P = 0.002); fPSA from 6.1 ± 4.8 to 3.9 ± 2.9 ng/mL (P = 0.045); and prostate volume from 101.8 ± 41.3 to 54.5 ± 24.8 cm(3) (P = 0.023). C. membranaceus shrinks the prostate and improves QoL.

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