Cerebral malaria is characterised by an accumulation of infected erythrocytes in the microvasculature of the brain. Plasmodium falciparum infected erythrocytes have been shown to bind to a Human Brain Endothelial Cell line (HBEC-5i) in vitro. This provides a model for the investigation of interactions between P. falcuparum and human brain endothelium. Currently neither the parasite adhesion ligands on infected erythrocytes, nor the host endothelial cell receptors necessary for this interaction have been identified. In this work, the identity of the host receptor on brain endothelial cells was addressed by binding assays of selected and unselected parasites on a wide range of malaria-associated host molecules. The identity of the parasite ligand was investigated by microarray analysis of parasites after selection for cytoadherence to HBEC-5i. The hypothesis being tested was that the gene encoding the parasite cytoadherence ligand would show significant upregulation in selected compared to unselected paarasites. The P. falciparum laboratory strains 3D7, HB3 and IT/FCR3 were selected for binding to HBEC-5i using a panning assay. Compared to unselected parasites, HBEC-5i selected parasites showed a distinct phenotype with reduced platelet-mediated clumping. There was no significant increase in binding of parasites to any of the known endothelial cytoadherence receptors for P. falciparum after selection on HBEC-5i. Binding inhibition assays with various antibodies and soluble receptors did not greatly block the adhesion of parasites to HBEC-5i except for heparin. Altogether, the receptor(s) mediating the interation with HBEC-5i remains unknown. In order to carry out transcriptional analysis of selected and unselected paarasites form all three parasite strains, it was necessary to update the existing microarray chip which is based on the 3D7 genome. This is because each parasite train has a unique repertoire of variant surface antigens (VSAs) including var, rif and stevor genes. Therefore, to fully analysis HB3 and IT genomes. Unique oligonnucleotide probes were then designed for each new sequence and the 3D7-based microarray chip was updated. Transcriptional analysis was then carried out on selected and unselected parasites of all strains. Microarray data clearly indicated that the most highly upregulated genes after selection were group A or group A-like var genes (HB3var3, 3D7_PFDOO2Oc, ITvar7 and ITvar19), showing 11 to over 100 fold upregulation in selected parasites. The rif gene adjacent to the upregulated var gene was also highly expressed. To a lesser extent some exported proteins like RESA-1, PfEMP3 or PHIST family members also showed increased transcription in HBEC-selected parasites (2-3 fold upregulation). Reverse transcriptase-PCR confirmed the upregulation of group A var genes in selected parasites, suggessted that the group A PfEMP1 variants are major candidate ligands for parasite binding to HBEC-5i. These findings are consistent with previous work showing an association between Group A var genes and cerebral malaria.

Malaria in pregnancy remains a public health challenge in Nigeria despite the fund appropriation for malaria control. The health challenges of malaria in pregnancy vary with populations and there is limited knowledge on the impact of the socioeconomic status and health-seeking behavior on malaria in pregnancy in Nigeria. The objective of this cross-sectional quantitative survey was to examine whether socioeconomic status and health-seeking behavior predict malaria in pregnancy in Nigeria using the social cognitive theoretical model. The data from a 2015 Nigeria Malaria Indicator Survey was used in this study. Data were analyzed using chi-square, binary, and multivariate logistics regression analyses. The study demonstrated that socioeconomic status (wealth index/income [Poorest: OR 2.709, 95% CI 1.869-3.928, p 0.000; Poorer: OR 1.791, 95% CI 1.256-2.555, p 0.00] and no education: OR 2.868, 95% CI 1.761-4.671, p 0.000) made significant contributions in predicting malaria in pregnancy. The research results also showed that socioeconomic status is a predictor of health-seeking behavior (wealth index/income [Poorest: OR 0.414, 95% CI 0.244-0.705, p 0.001], no education: OR 0.329, 95% CI 0.174-0.622, p 0.001 and primary education: OR 0.348, 95% CI 0.191-0.636, p 0.001). Additionally, the study findings showed that malaria in pregnancy determined the choice of formal health-seeking behavior by pregnant women (malaria in pregnancy: OR 0.551, 95% CI 0.469-0.648, p 0.000). The results of this research might guide Nigeria's Ministry of Health to develop approaches on women empowerment that would focus on socioeconomic status and health-seeking behavior of women such as programs to improve women's education and income generation.

Village Malaria Workers (VMWs) play an important role in the prevention and treatment of malaria as frontline volunteers in Cambodia, a nation implementing decentralisation initiatives and that is reliant on task shifting to address health worker shortages. Studying the performance of VMWs and understanding the social capital that they are able to mobilise, including enabling and reinforcing factors while fighting malaria in Cambodia’s Pailin province, will benefit performance enhancement and program scale up. This dissertation examines the factors associated with the perceived performance of VMWs, which has the potential to provide practical guidance for Cambodian health system managers and local health practitioners to capitalize on locally-available human resources to implement their health initiatives as per the country’s decentralisation plans. The study was done in 2 districts of Pailin province in Cambodia. The findings were based on 35 semi-structured surveys, 13 key informant interviews, 6 focus group discussions, 3 group interviews and 2 in-depth interviews covering VMWS and stakeholders from the commune council, village health support groups, health center management committee, provincial health offices, a referral hospital, a pharmacy, village chiefs, and administrative officials. The interviews and discussions were conducted using set guides, which allowed for flexibility and asking for follow-up questions as well as probing for more information and clarification. Pre-determined themes were used in designing the instruments, and data from the survey, focus groups, and interviews were thematically coded for manual data analysis. This study showed that VMWs’ performance is affected by a variety of factors that emerge from the complex context in which they work. These include socio-demographic variables; their health system knowledge; access to enabling and reinforcing factors, including family and social support; personal motivation; resource availability, including budget, supplies, and equipment; ways of being selected; access to learning, training and capacity-building opportunities; and institutional communication and implementation of decentralised health program. Factors such as perceived corruption also were seen to affect VMW’s performance. The participants suggested various ways to address these challenges. In order to improve the performance of VMWs, people’s participation in all local governance arms, including the CC, VHSG, HCMC and the HC, needs to be strengthened. The roles and expectations regarding citizen participation need to be clarified using simple messages. Training and capacity-building support needs to be made available for learning key new skills as relevant. The equipment and supplies necessary for work as well as adequate reimbursement of transportation allowances need to be provided along with instilling a proper system of VMW supervision and mentoring that adequately recognises those that are high performing. Targeted capacity assessments for VMWs and the VHSG, HC and HCMC need to be undertaken followed by needed training and mentoring in order to address areas that need further support to enhance productivity. A volunteer selection process needs to follow the rules described in the CPP policy ensuring deliberate attempts to open up entry points for public service to those that have been excluded on the basis of formal qualifications, lack of kinship, or political affiliation. / acase@tulane.edu

Malaria, an infectious disease caused by Plasmodium parasites, is one of the major world-scale health problems. Despite the efforts aimed at finding an effective way to control the disease, the success has been thwarted by the emergence of parasite drug resistance and mosquito resistance to insecticides. This thesis focuses on the genetic analysis of resistance to murine malaria induced by the lethal Plasmodium berghei ANKA using a wild-derived-inbred strain (WDIS). The aim of this thesis was to exploit the genetic diversity represented among WDIS for identifying loci contributing to resistance/susceptibility to murine malaria. The work included a genome-wide polymorphism survey using microsatellite markers performed on 10 WDIS. Comparisons of these strains to laboratory inbred strains confirmed a higher rate of polymorphism among the WDIS. We conclude that these WDIS represent repositories of unique naturally occurring genetic variability that may prove to be invaluable for the study of complex phenotypes. Next, we used the WDIS to search for novel phenotypes related to malaria pathogenesis. Whereas most laboratory strains were susceptible to experimental cerebral malaria (ECM) after infection with P. berghei ANKA, several WDIS were found to be resistant. To study the genetic inheritance of resistant/susceptibility to P. berghei ANKA infection we analysed backcross and F2 cohorts derived from crossing the WLA wild-derived strain with a laboratory mouse strain (C57BL/6). A novel phenotype represented by the cure of infection, clearance of parasitaemia and establishment of immunological memory was observed in the F2 progeny. The backcross progeny was used to genetically map one locus on chromosome 1 (Berr1) and one locus on chromosome 11 (Berr2) that mediate control of resistance to ECM induced by P. berghei ANKA. Genetic mapping using the F2 progeny showed that a locus on chromosome 1 (Berr1) and a locus on chromosome 9 (Berr3) were contributing to control survival time after infection with lethal Plasmodium. Finally, we identified, a locus on chromosome 4 (Berr4) that appears to control time of death due to hyperparasitaemia. This thesis underlines the value of using WDIS to reveal genetic factors involved in the aetiology of disease phenotypes. The characterisation of the genetic factors represented by the malaria resistance loci identified here are expected to provide a better understanding of the malaria pathology.

No description available.

South Africa is at the southern fringe of sub-Saharan African countries which persist in experiencing malaria transmission. The purpose of the study is to analyse the geographical and temporal patterns of malaria transmission from 2000 to 2011 using Bayesian geostatistical modelling in Limpopo Province, South Africa. Hereafter, develop malaria case data-driven spatio-temporal models to assess malaria transmission in Limpopo Province. Malaria case data was acquired from the South African Medical Research Council (MRC). Population data was acquired from AfriPopo; and Normalised Difference Vegetation Index (NDVI), Land Surface Temperature (LST) and Land Cover data were acquired from MODerate-resolution Imaging Spectro-radiometer (MODIS). Rainfall, Altitude and distance to water bodies’ data were acquired from African Data Dissemination Service (ADDS), United States Geological Survey (USGS) and Environmental Systems Research Institute (ESRI), respectively. Bayesian spatio-temporal incidence models were formulated for Gibbs variable selection and models were fitted using the best set of environmental factors. Modelbased predictions were obtained over a regular grid of 1 x 1km. spatial resolution covering the entire province and expressed as rates of per 1 000 inhabitants for the year 2010. To assess the performance of the predicted malaria incidence risk maps, the predictions and field observations were compared. The best set of environmental factors selected by variable selection was Altitude and the night temperature of two months before the case was reported. The environmental factors were then used for model fitting and all of the covariates were important on malaria risk. Predictions were done using all the environmental factors. The predictions showed that Vhembe and Mopani district municipalities have high malaria transmission as compared to other district municipalities in Limpopo Province. Assessment of predictive performance showed scatter plots with the coefficient of determination ( R² ). The values representing the statistical correlation represented by the coefficient of determination ( R² ) were 0.9798 (January), 0.8736 (February), 0.8152 (March), 0.8861 (April), 0.9949 (May), 0.3838 (June), 0.7794 (July), 0.9235 (September), 0.8966 (October), 0.9834 (November) and 0.8958 (December). August had two values reported and predicted which resulted in R² of 1. The numbers of the The produced malaria incidence maps can possibly be considered as one of the baselines for future malaria control programmes. The results highlighted the risk factors of malaria in Limpopo Province which are the most important characteristics of malaria transmission. / M.Sc. University of KwaZulu-Natal, Durban, 2013.

[pt] Em 2015 quase metade da população mundial vivia em área de risco de transmissão de malária. Neste mesmo ano, estimam-se 214 milhões de casos e 438 mil fatalidades. A principal forma de prevenção e redução da transmissão da malária é através do controle dos vetores, em particular, destaca-se o uso de mosquiteiros impregnados com inseticidas de longa duração (MILD). Neste contexto, os programas de distribuição de MILDS enfrentam desafios relacionados a obtenção de fundos e à gestão da cadeia de suprimentos como, por exemplo, incertezas associadas as atividades logísticas, as variáveis de oferta e demanda, e a volatilidade de preços. À luz destes fatos, esta dissertação propõe um modelo de otimização robusta, fundamentado em extensões dos arcabouços teóricos de Bertsimas e Sim (2004) e Fernandes et al. (2016), capaz de minimizar os custos de um programa de distribuição de mosquiteiros ou, dada uma restrição orçamentária, maximizar a distribuição para áreas prioritárias. Ademais, foi realizada uma revisão da literatura acadêmica acerca de modelos de otimização robusta aplicados no contexto da logística humanitária, onde alguns aspectos ainda pouco explorados foram ressaltados e considerados no modelo proposto. Um estudo de caso real é feito sobre um projeto feito do Fundo das Nações Unidas para crianças na Costa do Marfim. Os resultados apontam que conforme esperado, à medida que o nível de robustez considerado no modelo cresce, os custos totais também aumentam. Em contrapartida, o modelo robusto fornece soluções com maior flexibilidade na cadeia de suprimentos para a eventual necessidade de se ajustar os planos de compras e distribuição. Por fim, as soluções robustas foram avaliadas através de simulações de Monte Carlo, indicando que, conforme desejado, a probabilidade de viabilidade dos planos aumentam junto com nível de conservadorismo da solução. / [en] In 2015, almost half of the world population lived in areas at risk of malaria transmission. There were around 214 million malaria cases and 438,000 associated deaths. One of the major paths to prevent and reduce malaria transmission is through vector control, especially with the use of insecticide-treated nets (ITN). In this context, ITN distribution campaigns face several challenges, such as uncertainties related to funding, transportation, market and price volatility, which might be effectively tackled through long-term agreements and proper planning. However, that might not be an option for all humanitarian organizations and governments. Besides, considering uncertainties during budgetary planning is particular relevant. In this sense, a robust optimization model, based on Bertsimas and Sim (2004) and Fernandes et al. (2016) frameworks, is proposed to minimize the involved costs or, given a budget constraint, maximize the coverage of priority areas. A literature review on robust optimization applied to humanitarian logistics is conducted, in which aspects with less academic research attention are revealed and considered in the model, such as the simultaneous account of the aforementioned uncertainties and demand prioritization. A United Nations Children s Fund campaign in Ivory Coast is studied, and reveals that, as expected, as the robustness level increases so does the total costs. In return, the robust model generally provides a solution with improved supply chain flexibility, that might minimize efforts, in case it is necessary to adjust procurement and transportation plans when uncertainty is revealed. In addition, robust solutions were assessed through Monte Carlo simulations against several realizations of uncertain parameters values, pointing that, as desired, solution feasibility increases alongside the specified level of conservatism.

Orientadores: Marcelo Brocchi, Fabio Trindade Maranhão Costa / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-14T03:58:59Z (GMT). No. of bitstreams: 1 Franzin_FernandaMaria_M.pdf: 1412458 bytes, checksum: 2fe89ebc9e03c37ffcc48000024a232d (MD5) Previous issue date: 2009 / Resumo: A malária é uma doença tropical causada pelo parasita Plasmodium spp e é considerada um sério problema de saúde pública. São aproximadamente 500 milhões de casos anuais e mais de um milhão de mortes, especialmente na África e Ásia. No Brasil, são 500 mil novos casos por ano, principalmente na região Amazônica. Esses elevados índices de mortalidade e morbidade são motivadores da busca por estratégias de controle e eliminação dessa doença. A vacinação é uma ferramenta promissora no controle e prevenção da malária, entretanto, uma vacina segura e efetiva ainda não está disponível, em parte devido ao complexo ciclo de vida do parasita e a expressão de diferentes antígenos em cada fase. O antígeno de membrana similar ao ligante de eritrócitos (MAEBL), é um forte candidato a ser usado no desenvolvimento de uma vacina efetiva contra a malária, uma vez que esse antígeno é expresso em diferentes períodos do ciclo de vida do parasita. Neste estudo, o domínio M2 do antígeno MAEBL de Plasmodium yoelli foi expresso em linhagens vivas atenuadas de Salmonella enterica Typhimurium (?3987, ?4550 e H683) e o uso dessas bactérias como vacina recombinante potencialmente indutora de proteção contra malária murina foi avaliado. Essas linhagens foram obtidas após construção e transdução do plasmídio pYA3137trc contendo a região m2 do gene maebl e a expressão do antígeno foi confirmada por immunoblotting. A administração oral das linhagens recombinantes a camundongos BALB/c/AnUnib resultou na colonização dos tecidos hospedeiros apenas pela linhagem H683. Essa linhagem foi então avaliada em termos de indução de resposta imune humoral contra M2 e capacidade de imunização no modelo murino. Apesar da resposta humoral contra M2 ter sido detectada in vivo, a linhagem recombinante não demonstrou proteção potencial contra a infecção por Plasmodium yoelii no modelo murino. / Abstract: Malaria is a tropical disease caused by the parasite Plasmodium spp and is considered a serious public health problem. There are about 500 million annual cases and more than one million of deaths, especially in Africa and Asia. In Brazil, there are 500.000 new cases per year, mainly in the Amazon region. Those high rates mortality motivate the search for strategies of control and elimination of this illness. The vaccination is a promising tool in the control and prevention of malaria; however, a safe and effective vaccine is not available yet, in part due to the complex life cycle of the parasite and expression of different antigens in each phase. Membrane antigen erythrocyte binding like (MAEBL) is a strong candidate to be used in the development of an effective vaccine against malaria, since this antigen is expressed in different periods of the parasite life cycle. In this work, the M2 domain of Plasmodium yoelli MAEBL antigen was expressed in attenuated strains of Salmonella enterica Typhimurium (?3987, ?4550 e H683) and the use of these bacterias as potential inductor of protection against murine malaria was evaluated. These strains were obtained by construction and transduction of the plasmid pYA3137trc carrying the m2 region of the maebl gene and the antigen expression was confirmed by immunoblotting. The oral administration of the recombinant strains to BALB/c/AnUnib mice resulted in the colonization of host tissues only for the H683 strain. This strain was further evaluated in terms of induction of humoral immune response against M2 and immunization capacity in murine model. Even though humoral response against M2 was detected in vivo, the recombinant strains did not shown protective potential against the infection of Plasmodium yoelii in murine model. / Mestrado / Genetica de Microorganismos / Mestre em Genética e Biologia Molecular

Orientador: Liana Maria Cardoso Verinaud / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-23T07:43:36Z (GMT). No. of bitstreams: 1 Dionete_AllinyCarolina_M.pdf: 7519445 bytes, checksum: 4e7fd1c1acc58852052f9bc4765da65b (MD5) Previous issue date: 2012 / Resumo: O timo é um órgão linfóide primário localizado no mediastino anterior cuja função principal é o desenvolvimento das células T. Os precursores imaturos dos linfócitos T oriundos da medula óssea chegam ao timo através da junção córtico-medular e são denominados de timócitos. Estes timócitos passam por estágio denominados duplo-negativos (DN), não expressando os co-receptores CD4 e CD8, duplo positivos, expressando estes dois receptores e simples positivo, expressando somente um dos receptores. Desta forma, o completo desenvolvimento de células T torna-se dependente da constante migração dos precursores hematopoiéticos através do microambiente tímico que é composto por componentes linfóides e não linfóides. Já está bem documentada na literatura a importância que a matriz extracelular (MEC) exerce nos processos de migração dos timócitos. Durante todo este processo, os timócitos interagem com os componentes do microambiente tímico composto pela rede tridimensional formada por células epiteliais tímicas (TEC), macrófagos, células dendríticas, fibroblastos e componentes da matriz extracelular. Contudo, esta rede tridimensional pode ser remodelada pela ação de enzimas denominadas metaloproteinases de matriz (MMPs) que são capazes de degradar componentes da MEC revelando sítios de ligação para diversas integrinas e liberando fatores de crescimento e quimiocinas interligadas a esta rede. No timo já foram descritos vários membros da família das MMPs, como a MMP-2, 9, 14, 19 e ADAM 10, 17 e 28. Contudo, pouco se sabe sobre a atuação destas moléculas nos processos intratímicos . Estudos recentes do nosso grupo mostraram que a atrofia tímica induzida por P. berghei, um protozoário transmitido através da picada de um mosquito do gênero anófeles, leva a numerosas alterações no ambiente tímico. Assim, no presente trabalho pretende-se avaliar, quantitativamente e funcionalmente, possíveis alterações nas metaloproteinases MMP-2, 9, bem como nos seus inibidores TIMP-1, TIMP-2 durante a atrofia tímica observada após infecção pelo Plasmodium berghei NK65 / Abstract: The primary function of the thymus is to develop immature T-cells into cells that will be able to carry out immune functions. So, alterations in its microenvironment may disrupt intrathymic processes leading to an altered exportation of T cell to the periphery. We have recently showed that experimentally Plasmodium berghei-infected mice present severe thymic alterations characterized by atrophy with depletion of double-positive thymocytes, histological alterations with loss of delimitation between cortical and medullar regions, and altered expression of cytokines and its respective receptors. Besides, it was also observed that such alterations, conjunctively, are able to promote increase of thymocyte migratory activity. Considering that MMPs also have a crucial role in thymocyte migration, in this study we investigated alterations in the expression pattern and activity of matrix metalloproteinases MMP-2, 9, 14, 19 and ADAM-28, as well as in tissue inhibitors of metalloproteinases TIMP-1, TIMP-2 and RECK, by using the same experimental model. Our results show differential expression pattern of MMPs and TIMPs mRNAs among infected and non-infected mice. Besides, an imbalance between MMPs and their inhibitors those results in altered proteolytic activity were observed in thymus from infected mice. We hypothesize that disturbed MMP and TIMP expression and activity have also a role in the altered thymocyte migration through intrathymic microenvironments observed during plasmodium infection / Mestrado / Imunologia / Mestre em Genética e Biologia Molecular

No description available.