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BACKGROUND: Parkinson's disease (PD) is the second most common neurodegenerative disorder and, according to the Global Burden of Disease estimates in 2015, was the fastest growing neurological disorder globally with respect to associated prevalence, disability, and deaths. Information regarding the awareness, diagnosis, phenotypic characteristics, epidemiology, prevalence, risk factors, treatment, economic impact and lived experiences of people with PD from the African perspective is relatively sparse in contrast to the developed world, and much remains to be learned from, and about, the continent. METHODS: Transforming Parkinson's Care in Africa (TraPCAf) is a multi-faceted, mixed-methods, multi-national research grant. The study design includes multiple sub-studies, combining observational (qualitative and quantitative) approaches for the epidemiological, clinical, risk factor and lived experience components, as appropriate, and interventional methods (clinical trial component). The aim of TraPCAf is to describe and gain a better understanding of the current situation of PD in Africa. The countries included in this National Institute for Health and Care Research (NIHR) Global Health Research Group (Egypt, Ethiopia, Ghana, Kenya, Nigeria, South Africa and Tanzania) represent diverse African geographies and genetic profiles, with differing resources, healthcare systems, health and social protection schemes, and policies. The research team is composed of experts in the field with vast experience in PD, jointly led by a UK-based and Africa-based investigator. DISCUSSION: Despite the increasing prevalence of PD globally, robust data on the disease from Africa are lacking. Existing data point towards the poor awareness of PD and other neurological disorders on the continent and subsequent challenges with stigma, and limited access to affordable services and medication. This multi-site study will be the first of its kind in Africa. The data collected across the proposed sub-studies will provide novel and conclusive insights into the situation of PD. The selected country sites will allow for useful comparisons and make results relevant to other low- and middle-income countries. This grant is timely, as global recognition of PD and the public health challenge it poses builds. The work will contribute to broader initiatives, including the World Health Organization's Intersectoral global action plan on epilepsy and other neurological disorders. TRIAL REGISTRATION: https://doi.org/10.1186/ISRCTN77014546 .
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Salud Global , Enfermedad de Parkinson , Humanos , Enfermedad de Parkinson/epidemiología , Enfermedad de Parkinson/terapia , Atención a la Salud , Sudáfrica , NigeriaRESUMEN
BACKGROUND: Antenatal maternal psychological distress is common in low and middle-income countries (LMIC), but there is a dearth of research on its effect on birth and developmental outcomes in these settings, particularly in Sub-Saharan Africa. This study set out to identify risk factors for antenatal maternal psychological distress and determine whether antenatal maternal psychological distress was associated with infant birth and developmental outcomes, using data from the Drakenstein Child Health Study (DCHS), a birth cohort study in South Africa. METHODS: Pregnant women were enrolled in the DCHS from primary care antenatal clinics. Antenatal maternal psychological distress was measured using the Self-Reporting Questionnaire 20-item (SRQ-20). A range of psychosocial measures, including maternal childhood trauma, depression, and posttraumatic stress disorder (PTSD) were administered. Birth outcomes, including premature birth, weight-for-age z-score and head circumference-for-age z-score, were measured using revised Fenton growth charts. The Bayley III Scales of Infant and Toddler Development was administered at 6 months of age to assess infant development outcomes, including cognitive, language, and motor domains in a subset of n=231. Associations of maternal antenatal psychological distress with psychosocial measures, and with infant birth and developmental outcomes were examined using linear regression models. RESULTS: 961 women were included in this analysis, with 197 (21%) reporting scores indicating the presence of psychological distress. Antenatal psychological distress was associated with maternal childhood trauma, antenatal depression, and PTSD, and inversely associated with partner support. No association was observed between antenatal maternal psychological distress and preterm birth or early developmental outcomes, but antenatal maternal psychological distress was associated with a smaller head circumference at birth (coefficient=-0.30, 95% CI: -0.49; -0.10). CONCLUSION: Antenatal maternal psychological distress is common in LMIC settings and was found to be associated with key psychosocial measures during pregnancy, as well as with adverse birth outcomes, in our study population. These associations highlight the potential value of screening for antenatal maternal psychological distress as well as of developing targeted interventions.
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Desarrollo Infantil/fisiología , Complicaciones del Embarazo/psicología , Efectos Tardíos de la Exposición Prenatal/psicología , Distrés Psicológico , Adulto , Estudios de Cohortes , Familia , Femenino , Humanos , Lactante , Recién Nacido , Embarazo , Complicaciones del Embarazo/diagnóstico , Factores de Riesgo , Sudáfrica , Trastornos por Estrés Postraumático/diagnóstico , Trastornos por Estrés Postraumático/psicología , Encuestas y Cuestionarios , Adulto JovenRESUMEN
BACKGROUND: The RTS,S/AS01 vaccine targets the circumsporozoite protein of Plasmodium falciparum and has partial protective efficacy against clinical and severe malaria disease in infants and children. We investigated whether the vaccine efficacy was specific to certain parasite genotypes at the circumsporozoite protein locus. METHODS: We used polymerase chain reaction-based next-generation sequencing of DNA extracted from samples from 4985 participants to survey circumsporozoite protein polymorphisms. We evaluated the effect that polymorphic positions and haplotypic regions within the circumsporozoite protein had on vaccine efficacy against first episodes of clinical malaria within 1 year after vaccination. RESULTS: In the per-protocol group of 4577 RTS,S/AS01-vaccinated participants and 2335 control-vaccinated participants who were 5 to 17 months of age, the 1-year cumulative vaccine efficacy was 50.3% (95% confidence interval [CI], 34.6 to 62.3) against clinical malaria in which parasites matched the vaccine in the entire circumsporozoite protein C-terminal (139 infections), as compared with 33.4% (95% CI, 29.3 to 37.2) against mismatched malaria (1951 infections) (P=0.04 for differential vaccine efficacy). The vaccine efficacy based on the hazard ratio was 62.7% (95% CI, 51.6 to 71.3) against matched infections versus 54.2% (95% CI, 49.9 to 58.1) against mismatched infections (P=0.06). In the group of infants 6 to 12 weeks of age, there was no evidence of differential allele-specific vaccine efficacy. CONCLUSIONS: These results suggest that among children 5 to 17 months of age, the RTS,S vaccine has greater activity against malaria parasites with the matched circumsporozoite protein allele than against mismatched malaria. The overall vaccine efficacy in this age category will depend on the proportion of matched alleles in the local parasite population; in this trial, less than 10% of parasites had matched alleles. (Funded by the National Institutes of Health and others.).
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Vacunas contra la Malaria/inmunología , Malaria Falciparum/prevención & control , Plasmodium falciparum/genética , África , Femenino , Variación Genética , Humanos , Lactante , Malaria Falciparum/inmunología , Malaria Falciparum/parasitología , Masculino , Resultado del TratamientoRESUMEN
AIMS: Isolation and characterization of pectolytic bacteria associated with soft rot disease of potatoes in Nakuru, Kenya, to provide the basis for the development of disease control measures. METHODS AND RESULTS: Potato tubers showing symptoms of soft rot were collected from different farms in Molo and Mau Narok regions within Nakuru county. Isolation was done using crystal violet pectate medium (CVPM). Out of the 71 isolates that showed growth on CVPM, pathogenicity tests revealed that 36 of them had the ability to macerate tissues of potato tubers. All the isolates yielded a fragment of approximately 1500 bp after 16S rDNA amplification. Using the BIOLOG microbial identification system, 20 bacterial isolates were identified as Pectobacterium carotovorum subsp. carotovorum, 7 were Pseudomonas fluorescens B while 9 were Ps. fluorescens A. Y1/Y2 primers successfully amplified pectate lyase-encoding (pel) gene, approximately 434 bp, in all the 20 P. carotovorum species. The virulence of the isolated strains to cause disease, according to pectinolytic tests, varied with change in incubation temperature of the test samples. Pectobacterium carotovorum strains were the most virulent at 30°C while disease severity due to infection by Ps. fluorescens A strains was high at 20°C compared to the other isolates. CONCLUSION: This study reveals the identity of pectolytic bacterial species from two genera, Pectobacterium and Pseudomonas, as causative agents of potato soft rot in Nakuru, Kenya. SIGNIFICANCE AND IMPACT OF THE STUDY: Research findings from this study will aid in developing suitable risk mitigation methods for adoption by farmers to prevent losses due to soft rot.
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Pectobacterium carotovorum , Enfermedades de las Plantas/microbiología , Pseudomonas fluorescens , Solanum tuberosum/microbiología , Kenia , Pectobacterium carotovorum/genética , Pectobacterium carotovorum/patogenicidad , Pseudomonas fluorescens/genética , Pseudomonas fluorescens/patogenicidadRESUMEN
BACKGROUND: Giardia duodenalis is an important intestinal protozoan in humans worldwide with high infection rates occurring in densely populated and low resource settings. The parasite has been recorded to cause diarrhea in children. This study was carried out to identify G. duodenalis assemblages and sub-assemblages in children presenting with diarrhea in Kenya. METHODS: A total of 2112 faecal samples were collected from children aged ≤ 5 years and screened for the presence of Giardia cysts using microscopy. A total of 96 (4.5%) samples were identified as Giardia positive samples and were genotyped using glutamate dehydrogenase (gdh), triose phosphate isomerase (tpi) and ß-giardin loci. RESULTS: The three markers successfully genotyped 72 isolates and grouped 2 (1.4) isolates as Assemblage A, 64 (88.9) as Assemblage B and 7 (9.7%) consisted of mixed infections with assemblage A and B. A further analysis of 50 isolates using GDH Polymerase Chain Reaction and Restriction Fragment Length Polymorphism (PCR-RFLP) categorized 2 assemblage A isolates as sub-assemblage AII while 6 and 14 assemblage B isolates were categorized into sub-assemblage BIII and BIV respectively. A mixed infection with sub-assemblage BIII and BIV was recorded in 28 isolates. Over half (55.6%) of Giardia infections were recorded among the children between 13 to 48 months old. CONCLUSION: This paper reports the first data on the assemblages and sub-assemblages of Giardia duodenalis in children representing with diarrhea in Kenya.
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Giardia/genética , Giardiasis/epidemiología , Servicios de Salud del Niño , Preescolar , Diarrea/parasitología , Heces/parasitología , Femenino , Genotipo , Giardiasis/parasitología , Glutamato Deshidrogenasa/genética , Humanos , Lactante , Recién Nacido , Kenia/epidemiología , Masculino , Reacción en Cadena de la Polimerasa , Polimorfismo de Longitud del Fragmento de Restricción , Triosa-Fosfato Isomerasa/genéticaRESUMEN
BACKGROUND: Q fever in Kenya is poorly reported and its surveillance is highly neglected. Standard empiric treatment for febrile patients admitted to hospitals is antimalarials or penicillin-based antibiotics, which have no activity against Coxiella burnetii. This study aimed to assess the seroprevalence and the predisposing risk factors for Q fever infection in febrile patients from a pastoralist population, and derive a model for clinical prediction of febrile patients with acute Q fever. METHODS: Epidemiological and clinical data were obtained from 1067 patients from Northeastern Kenya and their sera tested for IgG antibodies against Coxiella burnetii antigens by enzyme-linked-immunosorbent assay (ELISA), indirect immunofluorescence assay (IFA) and quantitative real-time PCR (qPCR). Logit models were built for risk factor analysis, and diagnostic prediction score generated and validated in two separate cohorts of patients. RESULTS: Overall 204 (19.1 %, 95 % CI: 16.8-21.6) sera were positive for IgG antibodies against phase I and/or phase II antigens or Coxiella burnetii IS1111 by qPCR. Acute Q fever was established in 173 (16.2 %, 95 % CI: 14.1-18.7) patients. Q fever was not suspected by the treating clinicians in any of those patients, instead working diagnosis was fever of unknown origin or common tropical fevers. Exposure to cattle (adjusted odds ratio [aOR]: 2.09, 95 % CI: 1.73-5.98), goats (aOR: 3.74, 95 % CI: 2.52-9.40), and animal slaughter (aOR: 1.78, 95 % CI: 1.09-2.91) were significant risk factors. Consumption of unpasteurized cattle milk (aOR: 2.49, 95 % CI: 1.48-4.21) and locally fermented milk products (aOR: 1.66, 95 % CI: 1.19-4.37) were dietary factors associated with seropositivity. Based on regression coefficients, we calculated a diagnostic score with a sensitivity 93.1 % and specificity 76.1 % at cut off value of 2.90: fever >14 days (+3.6), abdominal pain (+0.8), respiratory tract infection (+1.0) and diarrhoea (-1.1). CONCLUSION: Q fever is common in febrile Kenyan patients but underappreciated as a cause of community-acquired febrile illness. The utility of Q fever score and screening patients for the risky social-economic and dietary practices can provide a valuable tool to clinicians in identifying patients to strongly consider for detailed Q fever investigation and follow up on admission, and making therapeutic decisions.
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Coxiella burnetii/aislamiento & purificación , Fiebre Q/epidemiología , Adolescente , Adulto , Animales , Antígenos Bacterianos/sangre , Niño , Preescolar , Coxiella burnetii/clasificación , Coxiella burnetii/inmunología , ADN Bacteriano/análisis , Ensayo de Inmunoadsorción Enzimática/veterinaria , Agricultores/estadística & datos numéricos , Femenino , Hospitalización/estadística & datos numéricos , Humanos , Lactante , Recién Nacido , Kenia/epidemiología , Ganado , Modelos Logísticos , Masculino , Persona de Mediana Edad , Fiebre Q/sangre , Fiebre Q/etiología , Reacción en Cadena en Tiempo Real de la Polimerasa , Factores de Riesgo , Sensibilidad y Especificidad , Estudios SeroepidemiológicosRESUMEN
Systemic lupus erythematosus (SLE) is a chronic autoimmune disorder characterized by inflammation of multiple organ systems and dysregulated interferon responses. SLE is both genetically and phenotypically heterogeneous, greatly reducing the power of case-control studies in SLE. Elevated circulating interferon-alpha (IFN-α) is a stable, heritable trait in SLE, which has been implicated in primary disease pathogenesis. About 40-50% of patients have high IFN-α, and high levels correspond with clinical differences. To study genetic heterogeneity in SLE, we performed a case-case study comparing patients with high vs low IFN-α in over 1550 SLE cases, including genome-wide association study and replication cohorts. In meta-analysis, the top associations in European ancestry were protein kinase, cyclic GMP-dependent, type I (PRKG1) rs7897633 (P(Meta) = 2.75 × 10(-8)) and purine nucleoside phosphorylase (PNP) rs1049564 (P(Meta) = 1.24 × 10(-7)). We also found evidence for cross-ancestral background associations with the ankyrin repeat domain 44 (ANKRD44) and pleckstrin homology domain containing, family F member 2 gene (PLEKHF2) loci. These loci have not been previously identified in case-control SLE genetic studies. Bioinformatic analyses implicated these loci functionally in dendritic cells and natural killer cells, both of which are involved in IFN-α production in SLE. As case-control studies of heterogeneous diseases reach a limit of feasibility with respect to subject number and detectable effect size, the study of informative pathogenic sub-phenotypes becomes an attractive strategy for genetic discovery in complex disease.
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Proteína Quinasa Dependiente de GMP Cíclico Tipo I/genética , Interferón-alfa/inmunología , Lupus Eritematoso Sistémico/genética , Lupus Eritematoso Sistémico/inmunología , Polimorfismo de Nucleótido Simple , Purina-Nucleósido Fosforilasa/genética , Estudios de Casos y Controles , Femenino , Redes Reguladoras de Genes , Humanos , Población Blanca/genéticaRESUMEN
Alleles of interferon (IFN) regulatory factor 8 (IRF8) are associated with susceptibility to both systemic lupus erythematosus (SLE) and multiple sclerosis (MS). Although high-type I IFN is thought to be causal in SLE, type I IFN is used as a therapy in MS. We investigated whether IRF8 alleles were associated with type I IFN levels or serologic profiles in SLE and MS. Alleles that have been previously associated with SLE or MS were genotyped in SLE and MS patients. The MS-associated rs17445836G allele was associated with anti-double-stranded DNA (dsDNA) autoantibodies in SLE patients (meta-analysis odds ratio=1.92). The same allele was associated with decreased serum IFN activity in SLE patients with anti-dsDNA antibodies, and with decreased type I IFN-induced gene expression in peripheral blood mononuclear cell from anti-dsDNA-negative SLE patients. In secondary progressive MS patients, rs17445836G was associated with decreased serum type I IFN. Rs17445836G was associated with increased IRF8 expression in SLE patient B cells. In summary, IRF8 rs17445836G is associated with human autoimmune disease characterized by low-type I IFN levels, and this may have pharmacogenetic relevance as type I IFN is modulated in SLE and MS. The association with autoantibodies and increased IRF8 expression in B cells supports a role for rs17445836G in humoral tolerance.
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Factores Reguladores del Interferón/genética , Interferón Tipo I/sangre , Lupus Eritematoso Sistémico/genética , Esclerosis Múltiple/genética , Polimorfismo de Nucleótido Simple , Autoanticuerpos/inmunología , Estudios de Casos y Controles , ADN/inmunología , Humanos , Lupus Eritematoso Sistémico/sangre , Lupus Eritematoso Sistémico/inmunología , Esclerosis Múltiple/sangre , Esclerosis Múltiple/inmunologíaRESUMEN
OBJECTIVE: To determine the antibiotic resistance patterns of pathogenic Escherichia coli on goat meat carcass at Huruma and Kiserian abattoirs in Kenya. DESIGN: Laboratory based study. SETTING: Huruma and Kiserian abattoirs in Kenya, SUBJECTS: 400 slaughtered goats inspected by veterinary health officers and approved for human consumption. METHODS: A Total of 400 slaughtered goats which were inspected by veterinary health officers and approved for human consumption were sampled from Huruma and Kiserian abattoir. Goat carcass swabs were collected by passing each swab tissue on four parts of the carcass mainly neck, right and left forelimbs, right and left hind limbs, and brisket. RESULTS: A total of 54 E. coli isolates were isolated and confirmed to be pathogenic. The percentage of isolates resistant to various microbial agents was recorded as follows: ampicillin (26 %), amoxycillin-clavulanic acid (17%), tetracycline (15%), chroramphenicol (4%), and ceftrixone (2% each). All Escherichia coli isolates were susceptible to gentamicin sulphamethaxazole-trimethomprin, kanamycin, cetriazididine (CAZ, 30pg), ciproxacin, nalidixic acid and chloramphenicol. Isolates were resistant to one or more of the antibiotics tested. Among the drugs tested, resistance was more frequently observed against ampicillin, amoxycillin-clavulanic acid, tetracycline, ceftrixone and chroramphenicol antibiotics. Among the isolates 26(48%) were positive for the stx1 gene, 19(35%) had the eae gene, 10(19%) possessed est gene,while 8(15%) harboured elt gene. Overall five isolates (10%) possessed aspu gene and two (4%) had aggR gene. No isolate possessed ipah gene. CONCLUSION: This study demonstrated that there is a significant level of antimicrobial resistance in pathogenic E. coli isolated from goat meat from Huruma and Kiserian abattoir. This indicates that goat meat from abattoirs could pose a risk of transmission of pathogenic antibiotic resistant strains to human. Poor hygienic standards and indiscriminate use of antimicrobials are the two main reasons for the presence of resistant pathogens in goat carcasses. RECOMMENDATIONS: Implemention of appropriate hygiene measures to control contamination of meat with pathogenic E. coli.
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Antiinfecciosos/farmacología , Farmacorresistencia Bacteriana , Infecciones por Escherichia coli , Escherichia coli , Carne , Mataderos/normas , Animales , Escherichia coli/efectos de los fármacos , Escherichia coli/aislamiento & purificación , Infecciones por Escherichia coli/epidemiología , Infecciones por Escherichia coli/prevención & control , Cabras , Análisis de Peligros y Puntos de Control Críticos/métodos , Humanos , Kenia/epidemiología , Carne/microbiología , Carne/normas , Pruebas de Sensibilidad Microbiana , Evaluación de NecesidadesRESUMEN
Worldwide, lack of access to safe drinking water together with inadequate sanitation and hygiene is an overwhelming contributor to approximately 4 billion cases of illness annually. This study was set out to understand the effects of hygiene and sanitation interventions on targeted health outcomes including diarrhoeal prevalence in children's of Turkana District, Kenya. The interventions undertaken included capacity building and empowerment approach to trigger communities to demand hygiene and sanitation facilities. Three hundred mothers were randomly sampled in a baseline survey carried out in 2007 and in a post-intervention survey carried out in 2008 (a repeat cross-sectional study design). Specimens were collected for microbiological tests of key diarrhoea related pathogens. Overall, Faecal coliform counts per 100 ml sample had significant variations between 2007 and 2008; in Kakuma, reduced from 88 to 30.2 colony units (P = 0.005), Lodwar Central where the number reduced from 91 to 17.3 units (P = 0.003), and in Lokichogio Division, the number reduced from 63.8 to 23.6 units (P = 0.006). From the 230 stool samples examined, the proportion of children from whom infectious pathogens of Proteus spp. was isolated reduced from 16 to 7 % while Escherichia coli reduced from 54 to 41 %. Overall, prevalence of diarrhoea related microbes in children aged <5 years reduced from 91.3 % in 2007 to 78.3 % after intervention (2008). It is notable that sanitation and hygiene promotion leads to significant reduction of diarrhoea prevalence in children aged <5 years. Its application should therefore be up-scaled in resource constrained areas.
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Diarrea/prevención & control , Promoción de la Salud/métodos , Higiene , Áreas de Pobreza , Saneamiento , Preescolar , Cloro/análisis , Estudios Transversales , Diarrea/epidemiología , Agua Potable/química , Enterobacteriaceae/aislamiento & purificación , Heces/microbiología , Humanos , Lactante , Kenia/epidemiología , Prevalencia , Evaluación de Programas y Proyectos de SaludRESUMEN
Lack of adequate sanitation, hygiene and safe portable water are serious global health problems that contribute to deaths of many children under the age of 5 years annually, mainly due to diarrhoeal diseases. This study was set out to determine the extent to which sanitation and hygiene promotion influenced mothers' and children's health in Turkana District; one of the arid Northern frontier Districts of Kenya. A repeat cross-sectional study design with multi-stage sampling method was used. A total of 300 mothers were randomly sampled for interviews in a baseline survey carried out in 2007 and in a post-intervention survey carried out in 2008. Data were collected using questionnaires and analyzed using SPSS for frequencies, cross tabulations and regression amongst other tests. Significant improvements were observed in hand washing practice, presence of hand washing soap at household and refuse pit ownership. In Kakuma Division the proportion of those who washed hands regularly increased from 48.8 to 91.3 % (χ(2) = 7.28, P = 0.122), in Lodwar Central, those who wash hands regularly increased from 85.5 to 89.9 % (χ² = 10.85, P = 0.028) while in Lokichogio, the proportions increased from 77.5 to 93.8 % (χ² = 15.56, P = 0.004). For hand washing soap at household, there was an increase in proportion of those who wash hands with soap from 65 to 78 % (χ² = 3.87, P = 0.049) within the group with no formal education. There was significant reduction of diarrhoea prevalence in children aged less than 5 years. Sanitation and hygiene promotion based on community participatory approaches can lead to significant reduction of diarrhoea in children.
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Diarrea/prevención & control , Promoción de la Salud/métodos , Higiene , Madres/psicología , Áreas de Pobreza , Saneamiento , Preescolar , Estudios Transversales , Diarrea/epidemiología , Femenino , Humanos , Lactante , Kenia/epidemiología , Madres/estadística & datos numéricos , Evaluación de Programas y Proyectos de Salud , Investigación CualitativaRESUMEN
Severe falciparum malaria is a major cause of preventable child mortality in sub-Saharan Africa. Plasma concentrations of P. falciparum Histidine-Rich Protein 2 (PfHRP2) have diagnostic and prognostic value in severe malaria. We investigate the potential use of plasma PfHRP2 and the sequestration index (the ratio of PfHRP2 to parasite density) as quantitative traits for case-only genetic association studies of severe malaria. Data from 2198 Kenyan children diagnosed with severe malaria, genotyped for 14 major candidate genes, show that polymorphisms in four major red cell genes that lead to hemoglobin S, O blood group, α-thalassemia, and the Dantu blood group, are associated with substantially lower admission plasma PfHRP2 concentrations, consistent with protective effects against extensive parasitized erythrocyte sequestration. In contrast the known protective ATP2B4 polymorphism is associated with higher plasma PfHRP2 concentrations, lower parasite densities and a higher sequestration index. We provide testable hypotheses for the mechanism of protection of ATP2B4.
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Antígenos de Grupos Sanguíneos , Eritrocitos , Malaria Falciparum , Antígenos de Protozoos/genética , Antígenos de Protozoos/metabolismo , Biomasa , Antígenos de Grupos Sanguíneos/metabolismo , Niño , Eritrocitos/parasitología , Humanos , Kenia , ATPasas Transportadoras de Calcio de la Membrana Plasmática/genética , Plasmodium falciparum/genética , Plasmodium falciparum/metabolismo , Proteínas Protozoarias/genética , Proteínas Protozoarias/metabolismoRESUMEN
Using a recombinant protein antigen for antibody testing shows a sum of antibody responses to multiple different immune epitopes existing in the protein antigen. In contrast, the antibody testing to an immunogenic peptide epitope reflects a singular antibody response to the individual peptide epitope. Therefore, using a panel of peptide epitopes provides an advantage for profiling multiple singular antibody responses with potential to estimate recent malaria exposure in human infections. However, transitioning from malaria immune epitope peptide-based ELISA to an all peptide bead-based multiplex Luminex assay presents some challenges including variation in the ability of different peptides to bind beads. The aim of this study was to develop a peptide coupling method while demonstrating the utility of these peptide epitopes from multiple stage antigens of Plasmodium falciparum for measuring antibodies. Successful coupling of peptide epitopes to beads followed three steps: 1) development of a peptide tag appended to the C-terminus of each peptide epitope consisting of beta-alanine-lysine (x 4)--cysteine, 2) bead modification with a high concentration of adipic acid dihydrazide, and 3) use of the peptide epitope as a blocker in place of the traditional choice, bovine serum albumin (BSA). This new method was used to couple 12 peptide epitopes from multiple stage specific antigens of P. falciparum, 1 Anopheles mosquito salivary gland peptide, and 1 Epstein-Barr virus peptide as an assay control. The new method was applied to testing of IgG in pooled samples from 30 individuals with previously repeated malaria exposure in western Kenya and IgM and IgG in samples from 37 U.S. travelers with recent exposure to malaria. The new peptide-bead coupling method and subsequent multiplex Luminex assay showed reliable detection of IgG to all 14 peptides in Kenyan samples. Among 37 samples from U.S. travelers recently diagnosed with malaria, IgM and IgG to the peptide epitopes were detected with high sensitivity and variation. Overall, the U.S. travelers had a much lower positivity rates of IgM than IgG to different peptide epitopes, ranging from a high of 62.2% positive for one epitope to a low of only 5.4% positive for another epitope. In contrast, the travelers had IgG positive rates from 97.3% to 91.9% to various peptide epitopes. Based on the different distribution in IgM and IgG positivity to overall number of peptide epitopes and to the number of pre-erythrocytic, erythrocytic, gametocytic, and salivary stage epitopes at the individual level, four distinct patterns of IgM and IgG responses among the 37 samples from US travelers were observed. Independent peptide-bead coupling and antibody level readout between two different instruments also showed comparable results. Overall, this new coupling method resolves the peptide-bead coupling challenge, is reproducible, and can be applied to any other immunogenic peptide epitopes. The resulting all peptide bead-based multiplex Luminex assay can be expanded to include other peptide epitopes of P. falciparum, different malaria species, or other diseases for surveillance, either in US travelers or endemic areas.
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Anticuerpos/análisis , Ensayo de Inmunoadsorción Enzimática , Epítopos/inmunología , Péptidos/química , Plasmodium falciparum/química , Anticuerpos/inmunología , Humanos , Péptidos/síntesis química , Péptidos/inmunología , Plasmodium falciparum/inmunologíaRESUMEN
Helicobacter pylori infection is the major cause of gastritis. Immunologically, H. pylori gastritis is associated with an infiltration of immune cells into gastric mucosa and the upregulation of various cytokines. Here, we analysed the gene expression of IL-1- and IL-17-related cytokines in regard to H. pylori infection in 85 German and 51 Kenyan patients with reflux-related or dyspeptic symptoms, respectively. Degree of gastritis and density of colonization were assessed histologically in accordance with the updated Sydney classification. Gene expression levels of cytokines IL-1ß, IL-8, IL-18, IL-33, IL-17A, IL-17F and IL-23 as well as IL-23R were analysed by real-time RT-PCR. In both populations, H. pylori-infected individuals had significant higher inflammatory scores for activity and chronicity than H. pylori-negative subjects (P values between 0.006 and <0.0001). IL-8 mRNA was induced up to 6-fold in H. pylori-infected patients (P < 0.05), while the expression levels of IL-1ß, IL-18, IL-23, IL-33 and IL-23R did not differ with respect to the H. pylori status in both groups. Most strikingly, a significant induction of both IL-17A and IL-17F was noted in H. pylori-infected individuals of both ethnic groups. Almost all IL-17F-positive samples revealed co-expression of IL-17A (40/42, 95.2%). Analysing IL-17A and IL-17F transcript levels of these 40 'double-positive' samples, a highly significant positive correlation between both genes was identified (P < 0.001). Taken together, H. pylori infection leads to a strong upregulation of both IL-17A and IL-17F in the gastric mucosa suggesting a regulatory link between both genes.
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Mucosa Gástrica/inmunología , Regulación de la Expresión Génica , Infecciones por Helicobacter/inmunología , Helicobacter pylori , Interleucina-17/genética , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Niño , Preescolar , Dispepsia/genética , Dispepsia/inmunología , Dispepsia/microbiología , Esofagitis Péptica/inmunología , Femenino , Mucosa Gástrica/microbiología , Alemania , Infecciones por Helicobacter/genética , Humanos , Lactante , Kenia , Masculino , Persona de Mediana Edad , Regulación hacia ArribaRESUMEN
OBJECTIVE: To characterise and investigate antimicrobial resistance of Esherichia coli and salmonella strains isolated from indigenous Gallus gallus in a leading slaughterhouse/market outlet in Nairobi-Kenya. DESIGN: A repeated cross sectional study and based on random sampling was used. SETTING: The study was carried out in a leading market outlet in Nairobi, Kenya. RESULTS: A hundred and four indigenous chicken rectal swabs were analysed, of which 67.3% were contaminated with Escherichia coli and 12.5% with Salmonella typhimurium. Seventy Escherichia coli isolates showed resistance phenotypes to one, two or more antibiotics. The most common antimicrobial resistance pattern was the single resistance to Tet (21.43%), followed by Amp Cot Tet (14%), Aug Amp Cot Tet (4.29%), Aug Amp Cot Tet Kan Chl (2.86%), Amp Cot Tet Chl, Cot Tet (2.86%) and Crx Amp Cot Tet Chl, Crx Amp Cot Chi, Amp Cot, Aug Amp, (1.43%) respectively. The highest rate of resistance was against Tet (55.7%), followed by Cot (40%). Third in line of resistance was Amp 32.86%, followed by Aug (11.43%), low or moderate resistance was against Chl (8.57%), Kan (4.29%), and Crx (2.86%) (P<0.0002). Salmonella typhimurium recovered displayed single resistance pattern to Tet (16.67%), Gen Cot Tet (8.33%), Amp Cot Tet (8.33%), Aug Amp Cot Tet (8.33%) and Amp Cot Tet Chl (16.67%). The highest resistance was against Tet (58.3%), Cot (41.7%), Amp (33.3%), Chl (16.7%), Aug and Gen (8.3%) respectively (P<0.0001). 3.0kb and 5.6kb plasmids isolated were not transferable by conjugation. CONCLUSION: Routine surveillance at slaughter/market outlets of Escherichia coli and Salmonella enterica should be done to identify infected flocks as a regulatory procedure for food safety and security programme.
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Mataderos , Pollos/microbiología , Farmacorresistencia Bacteriana Múltiple , Escherichia coli/aislamiento & purificación , Carne/microbiología , Salmonella enterica/aislamiento & purificación , Animales , Kenia , Pruebas de Sensibilidad MicrobianaRESUMEN
PfSPZ Vaccine, composed of radiation-attenuated, aseptic, purified, cryopreserved Plasmodium falciparum sporozoites, is administered by direct venous inoculation (DVI) for maximal efficacy against malaria. A critical issue for advancing vaccines that are administered intravenously is the ability to efficiently administer them across multiple age groups. As part of a pediatric safety, immunogenicity, and efficacy trial in western Kenya, we evaluated the feasibility and tolerability of DVI, including ease of venous access, injection time, and crying during the procedure across age groups. Part 1 was an age de-escalation, dose escalation trial in children aged 13 months-5 years and infants aged 5-12 months; part 2 was a vaccine efficacy trial including only infants, using the most skilled injectors from part 1. Injectors could use a vein viewer, if needed. A total of 1222 injections (target 0.5 mL) were initiated by DVI in 511 participants (36 were 5-9-year-olds, 65 were 13-59-month-olds, and 410 infants). The complete volume was injected in 1185/1222 (97.0%) vaccinations, 1083/1185 (91.4%) achieved with the first DVI. 474/511 (92.8%) participants received only complete injections, 27/511 (5.3%) received at least one partial injection (<0.5 mL), and in 10/511 (2.0%) venous access was not obtained. The rate of complete injections by single DVI for infants improved from 77.1% in part 1 to 92.8% in part 2. No crying occurred in 51/59 (86.4%) vaccinations in 5-9-year-olds, 25/86 (29.1%) vaccinations in 13-59-month-olds and 172/1067 (16.1%) vaccinations in infants. Mean administration time ranged from 2.6 to 4.6 minutes and was longer for younger age groups. These data show that vaccination by DVI was feasible and well tolerated in infants and children in this rural hospital in western Kenya, when performed by skilled injectors. We also report that shipping and storage in liquid nitrogen vapor phase was simple and efficient. (Clinicaltrials.gov NCT02687373).
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Vacunas contra la Malaria , Malaria Falciparum , Adolescente , Animales , Niño , Preescolar , Estudios de Factibilidad , Humanos , Lactante , Kenia , Malaria Falciparum/prevención & control , Plasmodium falciparum , Esporozoítos , Vacunación , Vacunas AtenuadasRESUMEN
Osteopontin (OPN) is a multifunctional cytokine involved in long bone remodeling and immune system signaling. Additionally, OPN is critical for interferon-alpha (IFN-alpha) production in murine plasmacytoid dendritic cells. We have previously shown that IFN-alpha is a heritable risk factor for systemic lupus erythematosus (SLE). Genetic variants of OPN have been associated with SLE susceptibility, and one study suggests that this association is particular to men. In this study, the 3' UTR SLE-risk variant of OPN (rs9138C) was associated with higher serum OPN and IFN-alpha in men (P=0.0062 and P=0.0087, respectively). In women, the association between rs9138 C and higher serum OPN and IFN-alpha was restricted to younger subjects, and risk allele carriers showed a strong age-related genetic effect of rs9138 genotype on both serum OPN and IFN-alpha (P<0.0001). In African-American subjects, the 5' region single nucleotide polymorphisms, rs11730582 and rs28357094, were associated with anti-RNP antibodies (odds ratio (OR)=2.9, P=0.0038 and OR=3.9, P=0.021, respectively). Thus, we demonstrate two distinct genetic influences of OPN on serum protein traits in SLE patients, which correspond to previously reported SLE-risk variants. This study provides a biologic relevance for OPN variants at the protein level, and suggests an influence of this gene on the IFN-alpha pathway in SLE.
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Interferón-alfa/inmunología , Lupus Eritematoso Sistémico/epidemiología , Lupus Eritematoso Sistémico/genética , Osteopontina/sangre , Osteopontina/genética , Adolescente , Adulto , Factores de Edad , Anciano , Niño , Femenino , Humanos , Lupus Eritematoso Sistémico/sangre , Lupus Eritematoso Sistémico/inmunología , Masculino , Persona de Mediana Edad , Factores Sexuales , Adulto JovenRESUMEN
OBJECTIVES: To assess the efficacy of amodiaquine-artesunate in an area with high chloroquine resistance in western Kenya. METHODS: Twenty-eight day in-vivo efficacy trial of amodiaquine-artesunate in 103 children aged 6-59 months in western Kenya with smear-confirmed uncomplicated Plasmodium falciparum malaria. RESULTS: The 28-day uncorrected adequate clinical and parasitological response (ACPR) was 69.0%, with 15.5% Late Clinical Failure and 15.5% Late Parasitologic Failure rates. The PCR-corrected 28-day ACPR was 90.2%. Clinical risk factors for recurrent infection (recrudescences and reinfections) were lower axillary temperature at enrollment and low weight-for-age Z-score. The presence of single nucleotide polymorphisms pfcrt 76T and pfmdr1 86Y at baseline was associated with increased risk of recurrent infections, both reinfections and recrudescences. CONCLUSION: Although artemether-lumefantrine (Coartem) is the first line ACT in Kenya, amodiaquine-artesunate is registered as an option for treatment of uncomplicated P. falciparum and remains an effective alternative to Coartem in western Kenya. Continued amodiaquine monotherapy in the private sector may jeopardize the future use of amodiaquine-artesunate as an alternative artemisinin-based combination therapy.
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Amodiaquina/uso terapéutico , Antimaláricos/uso terapéutico , Artemisininas/uso terapéutico , Malaria Falciparum/tratamiento farmacológico , Amodiaquina/efectos adversos , Animales , Antimaláricos/efectos adversos , Artemisininas/efectos adversos , Preescolar , Combinación de Medicamentos , Resistencia a Medicamentos , Femenino , Estudios de Seguimiento , Humanos , Lactante , Malaria Falciparum/parasitología , Masculino , Proteínas de Transporte de Membrana/genética , Proteínas Asociadas a Resistencia a Múltiples Medicamentos/genética , Plasmodium falciparum/efectos de los fármacos , Plasmodium falciparum/genética , Polimorfismo de Nucleótido Simple , Proteínas Protozoarias/genética , Recurrencia , Resultado del TratamientoRESUMEN
OBJECTIVES: To determine the quantity and quality of bacterial and fungi on money coins and to identify those that could pose a public health risk. DESIGN: Random sampling of coins from subjects within predetermined categories. SETTING: Westlands division of Nairobi Metropolitan province. SUBJECTS: Twenty-shilling coin samples were collected from matatu (a common commuter vehicle in Kenya) taxi conductors, greengrocers, shoe shiners, butchers, food kiosk/restaurant attendants, grocery shops attendants, roast maize vendors and school children. Forty coin samples were analysed for both the total viable content and the types of bacterial and fungal organisms. RESULTS: Average bacterial content on the coins ranged from 2.3 x 10(3) to 25.5 x 10(3) and fungi content from 11 to 377 colony forming units. The following potentially pathogenic bacteria were among those isolated: Escherichia coli, Klebsiella, Serratia, Enterobacter, Salmonella, Acinetobacter, Enterococci, Staphylococcus and Bacillus cereus. In addition, this is the first report of potentially pathogenic fungal isolation from money coins. Penicillium spp, Aspergillus niger, Fusarium, Rhizopus, Altenaria spp, Candida spp and Cryptococcus were isolated. CONCLUSION: Money coins harbour potentially pathogenic bacteria and fungi that may pose a public health risk. Hand hygiene is therefore strongly recommended, especially for those who simultaneously handle food and money.
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Bacterias/aislamiento & purificación , Enfermedades Transmisibles/transmisión , Fómites/microbiología , Hongos/aislamiento & purificación , Numismática , Infecciones Bacterianas/transmisión , Recuento de Colonia Microbiana , Humanos , Kenia , Micosis/transmisiónRESUMEN
OBJECTIVES: To determine the aetiology, epidemiology and sanitary factors of carriage of enteropathogenic Escherichia coli (EPEC) and Shiga-toxin producing E. coli (STEC) in food-handlers working in tourist hotels in three popular tourist destinations in Kenya. DESIGN: Cross sectional laboratory based study. SETTING: Three tourist destinations of Nairobi, Malindi and Diani in Kenya. SUBJECTS: Food handlers who were working in hotels frequented by tourists in the three study sites. RESULTS: Overall, during the period of April 2003 to May 2004, a total of 1399 food handlers stool samples were collected and analysed. EPEC expressing the eaeA gene and STEC expressing the stx2 gene were detected in 11/1399 (0.8%) and 2/1399 (0.1%) of the study subjects respectively. The mean age of the subjects from whom EPEC and STEC were isolated was similar (32.6 years) to those from whom no EPEC and STEC were isolated (32.5 years). Prior use of antibiotics, water source and toilet types were not significantly associated with the isolation of EPEC and STEC (p>0.05). There were 11 resistance patterns with six isolates (6/13, 46.2%) showing multidrug resistance. High prevalence of resistance was observed to co-trimoxazole (55.6%), chloramphenicol (33.3%), ampicillin (22.2%) and tetracycline (22.2%). High concentrations of antibiotics were required to achieve MIC90 for tetracycline, (>64 mg ml(-1)) and ampicillin (>256 mg ml(-1)). Cluster analysis of the Pulse Field Gel Electrophoresis profiles revealed that the EPEC and STEC isolates belonged to two main genotypes with 11 distinct DNA fragment profiles. CONCLUSION: This is the first report in Africa on the isolation of STEC from food handlers working in tourist hotels. These food handlers who carry the STEC and EPEC could potentially infect tourists and other people through food or water contamination in the hotel settings and thus our findings are of great public health importance.