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1.
Artículo en Inglés | MEDLINE | ID: mdl-34308445

RESUMEN

Recycling of electrical and electronic waste (e-waste) in developing countries is mostly conducted in the informal sector consisting of low skilled workers. Informal e-waste recycling predominantly involves the physically demanding work of manually collecting, dismantling and burning of e-waste items to extract reusable components and valuable metals including gold or copper. This cross-sectional study investigated the effects of manual e-waste recycling work on the musculoskeletal health of 176 workers at Agbogbloshie in Accra, Ghana - the largest informal e-waste dumpsites in Africa. Findings indicate significant associations between prolonged walking and weighted MSD symptom scores for the lower extremities, and between manual material handlings tasks and weighted MSD symptom scores for the upper extremities and lower back. The study calls attention to the need for ergonomics research in the informal work sector to promote safer practices and address a range of worker health concerns.

2.
Sci Transl Med ; 13(597)2021 06 09.
Artículo en Inglés | MEDLINE | ID: mdl-34108248

RESUMEN

Malaria vaccines that disrupt the Plasmodium life cycle in mosquitoes and reduce parasite transmission in endemic areas are termed transmission-blocking vaccines (TBVs). Despite decades of research, there are only a few Plasmodium falciparum antigens that indisputably and reproducibly demonstrate transmission-blocking immunity. So far, only two TBV candidates have advanced to phase 1/2 clinical testing with limited success. By applying an unbiased transcriptomics-based approach, we have identified Pf77 and male development gene 1 (PfMDV-1) as two P. falciparum TBV antigens that, upon immunization, induced antibodies that caused reductions in oocyst counts in Anopheles mosquito midguts in a standard membrane feeding assay. In-depth studies were performed to characterize the genetic diversity of, stage-specific expression by, and natural immunity to these two molecules to evaluate their suitability as TBV candidates. Pf77 and PfMDV-1 display limited antigenic polymorphism, are pan-developmentally expressed within the parasite, and induce naturally occurring antibodies in Ghanaian adults, which raises the prospect of natural boosting of vaccine-induced immune response in endemic regions. Together, these biological properties suggest that Pf77 and PfMDV-1 may warrant further investigation as TBV candidates.


Asunto(s)
Vacunas contra la Malaria , Malaria Falciparum , Animales , Anticuerpos Antiprotozoarios , Antígenos de Protozoos/genética , Ghana , Malaria Falciparum/prevención & control , Masculino , Plasmodium falciparum
3.
Int J Ind Ergon ; 822021 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-33767518

RESUMEN

Occupational exposure associated with unstructured, informal e-waste recycling has received very limited attention. This study aimed to quantify the occupational physical exposures among informal e-waste workers at the largest e-waste site in Africa. A cross-sectional field survey of 163 male e-waste workers was conducted using a self-report occupational physical activity questionnaire, along with direct work observations, and pedometer estimates of walking activity for a subset of workers (n = 42). Results indicated significant differences in self-reported 7-day work exposures among the three main e-waste job categories, namely, collectors (n = 70), dismantlers (n = 73) and burners (n = 20). Prolonged walking, sitting and standing on five or more days in the workweek was frequently reported by collectors (87%), dismantlers (82%) and burners (60%), respectively. Nearly 90% of collectors and burners and 60% of dismantlers reported lifting and carrying on five or more days in the workweek. The exposure combinations identified suggest a risk for musculoskeletal disorders (MSDs). Findings call attention to the need for research examining potential associations between physical exposures and MSDs affecting e-waste workers in Agbogbloshie. The high exposure variability both between and within workers has implications for future exposure assessments conducted in unregulated, informal work settings.

4.
Artículo en Inglés | MEDLINE | ID: mdl-33669889

RESUMEN

Informal recycling of electrical and electronic waste (e-waste) has myriad environmental and occupational health consequences, though information about the chronic musculoskeletal health effects on workers is limited. The aim of this study was to examine the prevalence and intensity of self-reported musculoskeletal disorder (MSD) symptoms among e-waste workers at Agbogbloshie in Ghana-the largest informal e-waste dumpsite in West Africa-relative to workers not engaged in e-waste recycling. A standardized musculoskeletal discomfort questionnaire was administered to 176 e-waste workers (73 collectors, 82 dismantlers, and 21 burners) and 41 workers in a reference group. The number of body parts with musculoskeletal discomfort were 1.62 and 1.39 times higher for collectors and dismantlers than burners, respectively. A 1-week discomfort prevalence was highest for collectors (91.8%) followed by dismantlers (89%), burners (81%), and the reference group (70.7%). The discomfort prevalence for e-waste workers was highest in the lower back (65.9%), shoulders (37.5%), and knees (37.5%). Whole-body pain scores (mean ± SE) were higher for collectors (83.7 ± 10.6) than dismantlers (45.5 ± 7.6), burners (34.0 ± 9.1), and the reference group (26.4 ± 5.9). Differences in prevalence, location, and intensity of MSD symptoms by the e-waste job category suggest specific work-related morbidity. Symptom prevalence and intensity call attention to the high risk for MSDs and work disability among informal e-waste workers, particularly collectors and dismantlers.


Asunto(s)
Residuos Electrónicos , Enfermedades Musculoesqueléticas , Exposición Profesional , Ghana/epidemiología , Humanos , Enfermedades Musculoesqueléticas/epidemiología , Exposición Profesional/análisis , Reciclaje
5.
Proc Hum Factors Ergon Soc Annu Meet ; 65(1): 715-719, 2021 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-35115743

RESUMEN

Rudimentary methods for electronic waste (e-waste) recycling employed in developing countries are a source of work-related musculoskeletal disorders (WRMSDs). A summarized comparison of WRMSDs and preliminary exposure assessment among e-waste dismantlers (D) and burners (B) in Agbogbloshie, Ghana is presented. A cross-sectional study was conducted to investigate WRMSDs and associated risk factors using the Cornell Musculoskeletal Discomfort Questionnaire and a newly developed ergonomic assessment tool. Results indicated higher WRMSDs prevalence in the lower back (68% D vs. 52% B; p = 0.172), shoulder (41% D vs. 29% B; p = 0.279) and upper arm (33% D vs 5% B; p = 0.010). Moderate to severe trunk flexion, high force exertion, repetition and vibration were prevalent risk factors among workers and were significantly higher in dismantlers than burners (p ≤ 0.001). Detailed ergonomic studies investigating the relationship between physical exposures and WRMSDs are needed to provide a deeper understanding of WRMSD causation in e-waste workers and more particularly in unstructured, unregulated work.

6.
Proc Hum Factors Ergon Soc Annu Meet ; 64(1): 905-909, 2020 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-33731982

RESUMEN

Most existing ergonomic assessment tools are intended for routine work. Time- and cost-efficient observational tools for ergonomic assessment of unregulated work are lacking. This paper presents the development of an observation-based tool designed to investigate ergonomic exposures among informal electronic waste workers that could be applied to other unregulated jobs/tasks. Real time coding of observation is used to estimate the relative duration, intensity, and frequency of exposure to key work postures, forceful exertions, movements, contact stress and vibration. Time spent in manual material handling activities such as carrying, lifting and pushing/pulling of working carts are also estimated. A preliminary study conducted with 6 e-waste workers showed that the tool can easily be used with minimal training and good inter-observer agreement (i.e., 89% to 100%) for most risk factors assessed. This new assessment tool provides effective and flexible options for quantifying ergonomic exposures among workers engaged in unregulated, highly variable work.

7.
Malar J ; 18(1): 116, 2019 Apr 02.
Artículo en Inglés | MEDLINE | ID: mdl-30940128

RESUMEN

BACKGROUND: Malaria remains a global public health problem responsible for 445,000 deaths in 2016. While microscopy remains the mainstay of malaria diagnosis, highly sensitive molecular methods for detection of low-grade sub-microscopic infections are needed for surveillance studies and identifying asymptomatic reservoirs of malaria transmission. METHODS: The Plasmodium falciparum genome sequence was analysed to identify high copy number genes that improve P. falciparum parasite detection in blood by RT-PCR. Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1)-specific primers were evaluated for P. falciparum detection in hospital-based microscopically positive dried blood spots and field-acquired whole blood from asymptomatic individuals from Ghana. RESULTS: PfEMP1 outperformed the Pf18S sequence for amplification-based P. falciparum detection. PfEMP1 primers exhibited sevenfold higher sensitivity compared to Pf18S primers for parasite genomic DNA. Probit analysis established a 95% detection threshold of 9.3 parasites/mL for PfEMP1 compared to 98.2 parasites/mL for Pf18S primers. The PfEMP1 primers also demonstrated superior clinical sensitivity, identifying 100% (20/20) of dried blood spot samples and 70% (69/98) of asymptomatic individuals as positive versus 55% (11/20) and 54% (53/98), respectively, for Pf18S amplification. CONCLUSIONS: These results establish PfEMP1 as a novel amplification target for highly sensitive detection of both acute infections from filter paper samples and submicroscopic asymptomatic low-grade infections.


Asunto(s)
Sangre/parasitología , Malaria Falciparum/diagnóstico , Técnicas de Diagnóstico Molecular/métodos , Plasmodium falciparum/aislamiento & purificación , Proteínas Protozoarias/genética , Reacción en Cadena en Tiempo Real de la Polimerasa/métodos , Adolescente , Adulto , Enfermedades Asintomáticas , Niño , Preescolar , Cartilla de ADN/genética , Femenino , Ghana , Humanos , Lactante , Masculino , Tamizaje Masivo/métodos , Plasmodium falciparum/genética , Sensibilidad y Especificidad
8.
Proc Hum Factors Ergon Soc Annu Meet ; 63(1): 938-942, 2019 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-33664560

RESUMEN

Electronic waste (e-waste) is a worldwide problem with regards to its increasing rate in the global waste stream. Its recycling is known to be associated with adverse health outcomes. The recycling site at Agbogbloshie is a major e-waste recycling hub which presents enormous health threats to the residents in this community as a result of exposure to complex mixtures of chemicals associated with the poor work methods employed. This paper describes the processes involved in e-waste recycling at Agbogbloshie and discusses some of the associated health and psychosocial challenges. Direct field observations and in-depth interviews of eight e-waste workers were conducted from November, 2017 to December, 2017. Results from a thematic analysis of obtained data suggest that inappropriate recycling methods, financial constraints, and the high physical demands of e-waste recycling work were associated with adverse musculoskeletal health conditions among the workers. A more systematic ergonomic study is currently being undertaken to quantify the associations between physical work exposures and worker musculoskeletal health among e-waste workers in Agbogbloshie. Further studies are needed that focus on locally adapted ergonomic interventions for effective recycling of e-waste and reducing the health risk to workers.

9.
Malar J ; 17(1): 468, 2018 Dec 14.
Artículo en Inglés | MEDLINE | ID: mdl-30547795

RESUMEN

BACKGROUND: This study seeks to compare the performance of HRP2 (First Response) and pLDH/HRP2 (Combo) RDTs for falciparum malaria against microscopy and PCR in acutely ill febrile children at presentation and follow-up. METHODS: This is an interventional study that recruited children < 5 years who reported to health facilities with a history of fever within the past 72 h or a documented axillary temperature of 37.5 °C. Using a longitudinal approach, recruitment and follow-up of participants was done between January and May 2012. Based on results of HRP2-RDT screening, the children were grouped into one of the following three categories: (1) tested positive for malaria using RDT and received anti-malarial treatment (group 1, n = 85); (2) tested negative for malaria using RDT and were given anti-malarial treatment by the admitting physician (group 2, n = 74); or, (3) tested negative for malaria using RDT and did not receive any anti-malarial treatment (group 3, n = 101). Independent microscopy, PCR and Combo-RDT tests were done for each sample on day 0 and all follow-up days. RESULTS: Mean age of the study participants was 22 months and females accounted for nearly 50%. At the time of diagnosis, the mean body temperature was 37.9 °C (range 35-40.1 °C). Microscopic parasite density ranged between 300 and 99,500 parasites/µL. With microscopy as gold standard, the sensitivity of HRP2 and Combo-RDTs were 95.1 and 96.3%, respectively. The sensitivities, specificities and predictive values for RDTs were relatively higher in microscopy-defined malaria cases than in PCR positive-defined cases. On day 0, participants who initially tested negative for HRP2 were positive by microscopy (n = 2), Combo (n = 1) and PCR (n = 17). On days 1 and 2, five of the children in this group (initially HRP2-negative) tested positive by PCR alone. On day 28, four patients who were originally HRP2-negative tested positive for microscopy (n = 2), Combo (n = 2) and PCR (n = 4). CONCLUSION: The HRP2/pLDH RDTs showed comparable diagnostic accuracy in children presenting with an acute febrile illness to health facilities in a hard-to-reach rural area in Ghana. Nevertheless, discordant results recorded on day 0 and follow-up visits using the recommended RDTs means improved malaria diagnostic capability in malaria-endemic regions is necessary.


Asunto(s)
Antimaláricos/uso terapéutico , Pruebas Diagnósticas de Rutina/estadística & datos numéricos , Fiebre/diagnóstico , Malaria Falciparum/diagnóstico , Plasmodium falciparum/aislamiento & purificación , Preescolar , Femenino , Fiebre/tratamiento farmacológico , Fiebre/parasitología , Ghana , Humanos , Lactante , Recién Nacido , Estudios Longitudinales , Malaria Falciparum/tratamiento farmacológico , Malaria Falciparum/parasitología , Masculino , Microscopía/métodos , Reacción en Cadena de la Polimerasa/métodos , Sensibilidad y Especificidad
10.
Malar J ; 17(1): 331, 2018 Sep 17.
Artículo en Inglés | MEDLINE | ID: mdl-30223841

RESUMEN

BACKGROUND: The gametocyte stage of Plasmodium falciparum is considered an important target for disrupting malaria transmission. Indications are that various demographic groups, such as children and pregnant women may differ in risk of harbouring gametocytes, which may be crucial for targeted control. In this study, the relationship between the prevalence and multiplicity of P. falciparum, asexual parasite infections and gametocytaemia was assessed in three different demographic groups in an area of southern Ghana with low malaria endemicity. Levels of antibody responses to Pfs230 were also assessed as a proxy for the presence of gametocytes. METHODS: The study involved multiple cross-sectional sampling of children (N = 184, aged 2-15 years), male and non-pregnant female adults (N = 154, aged 16-65 years) and pregnant women (N = 125, aged 18-45 years) from Asutsuare in the Shai Osudoku District of Greater Accra Region in Ghana. Asexual parasitaemia was detected by microscopy and PCR, and gametocytaemia was assessed by Pfs25-real time PCR. Multiclonal P. falciparum infections were estimated by msp2 genotyping and an indirect ELISA was used to measure plasma IgG antibodies to Pfs230 antigen. RESULTS: Overall, children and pregnant women had higher prevalence of submicroscopic gametocytes (39.5% and 29.7%, respectively) compared to adults (17.4%). Multiplicity of infection observed amongst children (3.1) and pregnant women (3.9) were found to be significantly higher (P = 0.006) compared with adults (2.7). Risk of gametocyte carriage was higher in individuals infected with P. falciparum having both Pfmsp2 3D7 and FC27 parasite types (OR = 5.92, 95% CI 1.56-22.54, P = 0.009) compared with those infected with only 3D7 or FC27 parasite types. In agreement with the parasite prevalence data, anti-Pfs230 antibody levels were lower in gametocyte positive adults (ß = - 0.57, 95% CI - 0.81, - 0.34, P < 0.001) compared to children. CONCLUSIONS: These findings suggest that children and pregnant women are particularly important as P. falciparum submicroscopic gametocyte reservoirs and represent important focus groups for control interventions. The number of clones increased in individuals carrying gametocytes compared to those who did not carry gametocytes. The higher anti-gametocyte antibody levels in children suggests recent exposure and may be a marker of gametocyte carriage.


Asunto(s)
Portador Sano/epidemiología , Malaria Falciparum/epidemiología , Plasmodium falciparum/aislamiento & purificación , Complicaciones Infecciosas del Embarazo/epidemiología , Adolescente , Adulto , Anticuerpos Antiprotozoarios/sangre , Antígenos de Protozoos/genética , Antígenos de Protozoos/inmunología , Portador Sano/parasitología , Niño , Preescolar , Estudios Transversales , Ensayo de Inmunoadsorción Enzimática , Femenino , Genotipo , Ghana/epidemiología , Humanos , Inmunoglobulina G/sangre , Malaria Falciparum/parasitología , Masculino , Microscopía , Persona de Mediana Edad , Parasitemia/epidemiología , Parasitemia/parasitología , Reacción en Cadena de la Polimerasa , Embarazo , Complicaciones Infecciosas del Embarazo/parasitología , Prevalencia , Proteínas Protozoarias/genética , Proteínas Protozoarias/inmunología , Adulto Joven
11.
Artículo en Inglés | MEDLINE | ID: mdl-29202097

RESUMEN

BACKGROUND: Malaria is one of the most challenging public health concerns in the developing world. To address its impact in endemic regions, several interventions are implemented by stakeholders. The Affordable Medicine Facility-malaria (AMFm) is an example of such interventions. Its activities include communication interventions to enhance the knowledge of caregivers of children under five years, licensed chemical sellers (LCS) and prescribers on malaria management with artemisinin-based combination therapy (ACT). This study was conducted to evaluate the effectiveness of the AMFm activities on malaria among targeted groups in two rural communities in Ghana. METHODS: A communication intervention study was conducted in the Asante-Akim North and South Districts of Ghana. Repeated cross-sectional pre and post surveys were deployed. Relevant malaria messages were designed and used to develop the information, education and communication (IEC) tools for the intervention. With the aid of posters and flipcharts developed by our study, community health workers (CHWs), prescribers, and licenced chemical sellers provided proper counselling to clients on malaria management. Trained CHWs and community based volunteers educated caregivers of children under five years on malaria management at their homes and at public gatherings such as churches, mosques, schools. Chi-square tests and logistic regression were run to determine associations and control for demographic differences respectively. RESULTS: There was significantly high exposure to malaria/ACT interventions in the intervention district than in the comparison district (OR = 16.02; 95% CI = 7.88-32.55) and same for malaria/ACT-related knowledge (OR = 3.63; 95% CI = 2.52-5.23). The participants in the intervention district were also more knowledgeable about correct administration of dispersible drug for children <5 years than their counterparts in the unexposed district. CONCLUSION: Our data show that targeted interventions improve malaria based competences in rural community settings. The availability of subsidized ACTs and the intensity of the communication campaigns contributed to the AMFm-related awareness, improved knowledge on malaria/ACTs and management practices.

12.
Malar J ; 16(1): 224, 2017 05 26.
Artículo en Inglés | MEDLINE | ID: mdl-28549426

RESUMEN

BACKGROUND: Women exposed to Plasmodium infection develop antibodies and become semi-immune. This immunity is suppressed during pregnancy making both the pregnant woman and the foetus vulnerable to the adverse effects of malaria, particularly by Plasmodium falciparum. Intermittent preventive treatment of malaria in pregnancy (IPTp) with Sulfadoxine-pyrimethamine (SP) tablets is one of the current interventions to mitigate the effects of malaria on both the pregnant woman and the unborn child. The extent to which IPTp may interfere with the acquisition of protective immunity against pregnancy-associated malaria (PAM) is undefined in Ghana. METHODS: Three-hundred-and-twenty pregnant women were randomly enrolled at the antenatal clinic (ANC) in Madina, Accra. Venous blood samples were obtained at first ANC registration and at 4-week intervals (post-IPTp administration). Placental and cord blood samples were obtained at delivery and the infants were followed monthly for 6 months after birth. Anti-IgG and IgM antibodies against a crude antigen preparation and the glutamate-rich protein (GLURP) of P. falciparum were quantified by the enzyme-linked immunosorbent assay (ELISA). RESULTS: There was a general decline in the trend of mean concentrations of all the antibodies from enrolment to delivery. The levels of antibodies in cord blood and placenta were well correlated. Children did not show clinical signs of malaria at 6 months after birth. CONCLUSIONS: IgG against both crude antigen and GLURP were present in placenta and cord blood and it is therefore concluded that there is a trend of declining antibody from enrolment to delivery and IPTp-SP may have reduced malaria exposure, however, this does not impact on the transfer of antibodies to the foetus in utero. The levels of maternal and cord blood antibodies at delivery showed no adverse implications on malaria among the children at 6 months. However, the quantum and quality of the antibody transferred needs further investigation to ensure that the infants are protected from severe episodes of malaria.


Asunto(s)
Anticuerpos Antiprotozoarios/sangre , Inmunoglobulina G/sangre , Inmunoglobulina M/sangre , Malaria Falciparum/inmunología , Plasmodium falciparum/inmunología , Antimaláricos/uso terapéutico , Femenino , Sangre Fetal/inmunología , Ghana , Humanos , Lactante , Recién Nacido , Malaria Falciparum/tratamiento farmacológico , Malaria Falciparum/parasitología , Placenta/inmunología , Embarazo
13.
Malar J ; 16(1): 58, 2017 02 01.
Artículo en Inglés | MEDLINE | ID: mdl-28148260

RESUMEN

BACKGROUND: Diagnosis of Plasmodium falciparum is often based on detection of histidine-rich protein 2 (HRP2) in blood. Most HRP2-based assays have high sensitivity and specificity; however, authors have suggested that antibodies (Ab) to HRP2 could reduce assay sensitivity. This study sought to characterize the antibody response to HRP2 with respect to prevalence, class, subclass, affinity, and age distribution in Cameroonian children and adults residing in an area with high P. falciparum transmission. METHODS: Plasma samples from 181 Cameroonian children and adults who had been repeatedly exposed to P. falciparum and 112 samples from American adults who had never been exposed were tested for IgG Ab to HRP2. For comparison, Ab to the merozoite antigens MSP1, MSP2, MSP3 and the pregnancy-associated antigen VAR2CSA were measured using a multiplex bead-based assay. In addition, 81 plasma samples from slide-positive individuals were screened for IgM Ab to HRP2. RESULTS: As expected, children and adults had IgG Ab to MSP1, MSP2 and MSP3, antibody levels increased with age, and only women of child-bearing age had Ab to VAR2CSA; however, no convincing evidence was found that these individuals had an acquired antibody response to HRP2. That is, using two sources of recombinant HRP2, identical results were obtained when plasma from 110 Cameroonian adults and 112 US adults were screened for IgG Ab. Further studies showed that antibody prevalence and levels did not increase with age in Cameroonians between ages 5 and >80 years. Although a few samples from slide-positive Cameroonians had IgM values slightly above the American cut-off, it was unclear if the individuals had a true IgM response to HRP2 or if the values were due to non-specific binding from elevated immunoglobulin levels associated with infection. Data from prediction models showed a paucity of Class II T cell epitopes in HRP2. CONCLUSIONS: These data support the conclusion that most individuals in malaria-endemic areas do not produce an acquired humoral response to HRP2. The absence of Ab helps explain why HRP2-based assays are able to detect nanogram amounts of HRP2 and why HRP2 continues to circulate for a long time after parasite clearance.


Asunto(s)
Anticuerpos Antiprotozoarios/sangre , Antígenos de Protozoos/inmunología , Enfermedades Endémicas , Malaria Falciparum/inmunología , Proteínas Protozoarias/inmunología , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Antígenos de Protozoos/sangre , Camerún/epidemiología , Niño , Preescolar , Estudios Transversales , Femenino , Humanos , Inmunoglobulina M/sangre , Malaria Falciparum/epidemiología , Masculino , Proteína 1 de Superficie de Merozoito/sangre , Persona de Mediana Edad , Embarazo , Proteínas Protozoarias/sangre , Estados Unidos , Adulto Joven
15.
Malar J ; 15(1): 532, 2016 Nov 04.
Artículo en Inglés | MEDLINE | ID: mdl-27814765

RESUMEN

BACKGROUND: Antigenic variation of Plasmodium falciparum erythrocyte membrane protein 1 is a key parasite mechanism for immune evasion and parasite survival. It is assumed that the number of parasites expressing the same var gene must reach high enough numbers before the host can produce detectable levels of antibodies (Ab) to the variant. VAR2CSA is a protein coded for by one of 60 var genes that is expressed on the surface of infected erythrocytes (IE) and mediates IE binding to the placenta. The idea that Ab to VAR2CSA are pregnancy-associated was challenged when VAR2CSA-specific Ab were reported in children and men. However, the frequency and conditions under which Ab to VAR2CSA are produced outside pregnancy is unclear. This study sought to determine frequency, specificity and level of Ab to VAR2CSA produced in children and whether children with hyperparasitaemia and severe malaria are more likely to produce Ab to VAR2CSA compared to healthy children. METHODS: Antibody responses to a panel of recombinant proteins consisting of multiple VAR2CSA Duffy-binding-like domains (DBL) and full-length VAR2CSA (FV2) were characterized in 193 1-15 year old children from rural Cameroonian villages and 160 children with severe malaria from the city. RESULTS: Low Ab levels to VAR2CSA were detected in children; however, Ab levels to FV2 in teenagers were rare. Children preferentially recognized DBL2 (56-70%) and DBL4 (50-60%), while multigravidae produced high levels of IgG to DBL3, DBL5 and FV2. Sixty-seven percent of teenage girls (n = 16/24) recognized ID1-ID2a region of VAR2CSA. Children with severe forms of malaria had significantly higher IgG to merozoite antigens (all p < 0.05), but not to VAR2CSA (all p > 0.05) when compared to the healthy children. CONCLUSION: The study suggests that children, including teenage girls acquire Ab to VAR2CSA domains and FV2, but Ab levels are much lower than those needed to protect women from placental infections and repertoire of Ab responses to DBL domains is different from those in pregnant women. Interestingly, children with severe malaria did not have higher Ab levels to VAR2CSA compared to healthy children.


Asunto(s)
Anticuerpos Antiprotozoarios/sangre , Formación de Anticuerpos , Antígenos de Protozoos/inmunología , Plasmodium falciparum/inmunología , Adolescente , Camerún , Niño , Preescolar , Estudios Transversales , Femenino , Humanos , Lactante , Estudios Longitudinales , Masculino
16.
PLoS Negl Trop Dis ; 10(10): e0005029, 2016 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-27706158

RESUMEN

Plasmodium vivax is the most prevalent cause of human malaria in the world and can lead to severe disease with high potential for relapse. Its genetic and geographic diversities make it challenging to control. P. vivax is understudied and to achieve control of malaria in endemic areas, a rapid, accurate, and simple diagnostic tool is necessary. In this pilot study, we found that a colorimetric system using AuNPs and MSP10 DNA detection in urine can provide fast, easy, and inexpensive identification of P. vivax. The test exhibited promising sensitivity (84%), high specificity (97%), and only mild cross-reactivity with P. falciparum (21%). It is simple to use, with a visible color change that negates the need for a spectrometer, making it suitable for use in austere conditions. Using urine eliminates the need for finger-prick, increasing both the safety profile and patient acceptance of this model.


Asunto(s)
Colorimetría/métodos , Malaria Vivax/diagnóstico , Nanopartículas del Metal , Oligonucleótidos , Plasmodium vivax/aislamiento & purificación , Orina/parasitología , Antígenos de Protozoos/genética , Colorimetría/economía , Colorimetría/normas , Reacciones Cruzadas , ADN Protozoario/orina , Oro , Humanos , Malaria Vivax/parasitología , Malaria Vivax/orina , Tamizaje Masivo , Microscopía , Parasitemia/diagnóstico , Parasitemia/parasitología , Proyectos Piloto , Plasmodium vivax/genética , Plasmodium vivax/ultraestructura , Proteínas Protozoarias/genética , Sensibilidad y Especificidad
17.
Trop Med Int Health ; 21(10): 1263-1271, 2016 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-27546068

RESUMEN

OBJECTIVE: To generate monoclonal antibodies (MAbs) for developing a rapid malaria diagnostic urine-based assay (RUBDA), using Plasmodium-infected human urinary antigens. METHODS: Plasmodium-infected human urinary (PAgHU) and cultured parasite (CPfAg) antigens were used to generate mouse MAbs. The reactivity and accuracy of the MAbs produced were then evaluated using microplate ELISA, SDS-PAGE, Western blotting assay, microscopy and immunochromatographic tests. RESULTS: Ninety-six MAb clones were generated, of which 68.8% reacted to both PAgHU and CPfAg, 31.3% reacted to PAgHU only, and none reacted to CPfAg only. One promising MAb (UCP4W7) reacted in WBA, to both PAgHU and CPfAg, but not to Plasmodium-negative human urine and blood, Schistosoma haematobium and S. mansoni antigens nor measles and poliomyelitis vaccines. CONCLUSION: MAb UCP4W7 seems promising for diagnosing Plasmodium infection. Urine is a reliable biomarker source for developing non-invasive malaria diagnostic tests. SDS-PAGE and MAb-based WBA appear explorable in assays for detecting different levels of Plasmodium parasitaemia.


Asunto(s)
Anticuerpos Monoclonales/orina , Antígenos de Protozoos/orina , Pruebas Diagnósticas de Rutina , Malaria/orina , Urinálisis/métodos , Animales , Estudios Transversales , Ghana , Humanos , Ratones , Ratones Endogámicos BALB C , Plasmodium , Sensibilidad y Especificidad
18.
Malar J ; 15(1): 263, 2016 05 10.
Artículo en Inglés | MEDLINE | ID: mdl-27160685

RESUMEN

BACKGROUND: The Affordable Medicine Facility-malaria (AMFm) was an innovative global financing mechanism for the provision of quality-assured artemisinin-based combination therapy (ACT) across both the private and public health sectors in eight countries in sub-Saharan Africa. This study evaluated the effectiveness of AMFm subsidies in increasing access to ACT in Ghana and documented malaria management practices at the household and community levels during the implementation of the AMFm. METHODS: This study, conducted in four regions in Ghana between January, 2011 to December, 2012, employed cross-sectional mixed-methods design that included qualitative and quantitative elements, specifically household surveys, focus group discussions (FGD) and in-depth interviews. RESULTS: The study indicated high ACT availability, adequate provider knowledge and reasonably low quality-assured ACT use in the study areas, all of which are a reflection of a high market share of ACT in these hard-to-reach areas of the country. Adequate recognition of childhood malaria symptoms by licensed chemical seller (LCS) attendants was observed. A preference by caregivers for LCS over health facilities for seeking treatment solutions to childhood malaria was found. CONCLUSIONS: Artemisinin-based combination therapy with the AMFm logo was accessible and affordable for most people seeking treatment from health facilities and LCS shops in rural areas. Caregivers and LCS were seen to play key roles in the health of the community especially with children under 5 years of age.


Asunto(s)
Antimaláricos/uso terapéutico , Artemisininas/uso terapéutico , Cuidadores/psicología , Investigación sobre Servicios de Salud , Lactonas/uso terapéutico , Malaria/diagnóstico , Malaria/tratamiento farmacológico , Farmacéuticos/psicología , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Niño , Preescolar , Estudios Transversales , Quimioterapia Combinada/métodos , Femenino , Ghana/epidemiología , Conocimientos, Actitudes y Práctica en Salud , Accesibilidad a los Servicios de Salud , Humanos , Lactante , Recién Nacido , Entrevistas como Asunto , Malaria/prevención & control , Masculino , Persona de Mediana Edad , Aceptación de la Atención de Salud , Adulto Joven
19.
PLoS One ; 9(2): e88173, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-24505415

RESUMEN

In pregnant women, Plasmodium falciparum-infected erythrocytes expressing the VAR2CSA antigen bind to chondroitin sulfate A in the placenta causing placental malaria. The binding site of VAR2CSA is present in the ID1-ID2a region. This study sought to determine if pregnant Cameroonian women naturally acquire antibodies to ID1-ID2a and if antibodies to ID1-ID2a correlate with absence of placental malaria at delivery. Antibody levels to full-length VAR2CSA and ID1-ID2a were measured in plasma samples from 745 pregnant Cameroonian women, 144 Cameroonian men, and 66 US subjects. IgM levels and IgG avidity to ID1-ID2a were also determined. As expected, antibodies to ID1-ID2a were absent in US controls. Although pregnant Cameroonian women developed increasing levels of antibodies to full-length VAR2CSA during pregnancy, no increase in either IgM or IgG to ID1-ID2a was observed. Surprisingly, no differences in antibody levels to ID1-ID2a were detected between Cameroonian men and pregnant women. For example, in rural settings only 8-9% of males had antibodies to full-length VAR2CSA, but 90-96% had antibodies to ID1-ID2a. In addition, no significant difference in the avidity of IgG to ID1-ID2a was found between pregnant women and Cameroonian men, and no correlation between antibody levels at delivery and absence of placental malaria was found. Thus, the response to ID1-ID2a was not pregnancy specific, but predominantly against cross-reactivity epitopes, which may have been induced by other PfEMP1 antigens, malarial antigens, or microbes. Currently, ID1-ID2a is a leading vaccine candidate, since it binds to the CSA with the same affinity as the full-length molecule and elicits binding-inhibitory antibodies in animals. Further studies are needed to determine if the presence of naturally acquired cross-reactive antibodies in women living in malaria endemic countries will alter the response to ID1-ID2a following vaccination with ID1-ID2a.


Asunto(s)
Anticuerpos Antiprotozoarios/inmunología , Formación de Anticuerpos/inmunología , Antígenos de Protozoos/inmunología , Complicaciones Parasitarias del Embarazo/inmunología , Proteínas Recombinantes/inmunología , Adolescente , Adulto , Anticuerpos Antiprotozoarios/sangre , Sitios de Unión/inmunología , Camerún , Reacciones Cruzadas/inmunología , Epítopos/inmunología , Eritrocitos/inmunología , Eritrocitos/parasitología , Femenino , Humanos , Inmunoglobulina G/sangre , Inmunoglobulina G/inmunología , Inmunoglobulina M/sangre , Inmunoglobulina M/inmunología , Malaria Falciparum/inmunología , Masculino , Placenta/inmunología , Placenta/parasitología , Plasmodium falciparum/inmunología , Embarazo , Complicaciones Parasitarias del Embarazo/sangre , Complicaciones Parasitarias del Embarazo/parasitología , Adulto Joven
20.
BMC Res Notes ; 6: 350, 2013 Sep 03.
Artículo en Inglés | MEDLINE | ID: mdl-24007344

RESUMEN

BACKGROUND: Malaria and HIV infections during pregnancy can individually or jointly unleash or confound pregnancy outcomes. Two of the probable outcomes are fetal anemia and cord blood malaria parasitemia. We determined clinical and demographic factors associated with fetal anemia and cord blood malaria parasitemia in newborns of HIV-positive women from two districts in Ghana. RESULTS: We enrolled 1,154 antenatal attendees (443 HIV-positive and 711 HIV-negative) of which 66% were prospectively followed up at delivery. Maternal malaria parasitemia, and anemia rates among HIV+ participants at enrolment were 20.3% and 78.7% respectively, and 12.8% and 51.6% among HIV- participants. Multivariate linear and logistic regression models were used to study associations. Prevalence of fetal anemia (cord hemoglobin level < 12.5 g/dL) and cord parasitemia (presence of P. falciparum in cord blood at delivery) were 57.3% and 24.4% respectively. Factors found to be associated with fetal anemia were maternal malaria parasitemia and maternal anemia. Infant cord hemoglobin status at delivery was positively and significantly associated with maternal hemoglobin and gestational age whilst female gender of infant was negatively associated with cord hemoglobin status. Maternal malaria parasitemia status at recruitment and female gender of infant were positively associated with infant cord malaria parasitemia status. CONCLUSIONS: Our data show that newborns of women infected with HIV and/or malaria are at increased risk of anemia and also cord blood malaria parasitemia. Prevention of malaria infection during pregnancy may reduce the incidence of both adverse perinatal outcomes.


Asunto(s)
Anemia/diagnóstico , Infecciones por VIH/diagnóstico , Transmisión Vertical de Enfermedad Infecciosa , Malaria Falciparum/diagnóstico , Parasitemia/diagnóstico , Complicaciones Parasitarias del Embarazo/diagnóstico , Adolescente , Adulto , Anemia/sangre , Anemia/epidemiología , Coinfección , Femenino , Sangre Fetal/parasitología , Hemoglobina Fetal/metabolismo , Ghana/epidemiología , Infecciones por VIH/sangre , Infecciones por VIH/epidemiología , Infecciones por VIH/transmisión , Humanos , Lactante , Recién Nacido , Malaria Falciparum/sangre , Malaria Falciparum/epidemiología , Malaria Falciparum/transmisión , Masculino , Parasitemia/sangre , Parasitemia/epidemiología , Parasitemia/transmisión , Embarazo , Complicaciones Parasitarias del Embarazo/sangre , Complicaciones Parasitarias del Embarazo/epidemiología , Resultado del Embarazo , Prevalencia , Factores Sexuales
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