RESUMEN
Identifying the species of the subfamily Anophelinae that are Plasmodium vectors is important to vector and malaria control. Despite the increase in cases, vector mosquitoes remain poorly known in Brazilian indigenous communities. This study explores Anophelinae mosquito diversity in the following areas: (1) a Yanomami reserve in the northwestern Amazon Brazil biome and (2) the Pantanal biome in southwestern Brazil. This is carried out by analyzing cytochrome c oxidase (COI) gene data using Refined Single Linkage (RESL), Assemble Species by Automatic Partitioning (ASAP), and tree-based multi-rate Poisson tree processes (mPTP) as species delimitation approaches. A total of 216 specimens collected from the Yanomami and Pantanal regions were sequenced and combined with 547 reference sequences for species delimitation analyses. The mPTP analysis for all sequences resulted in the delimitation of 45 species groups, while the ASAP analysis provided the partition of 48 groups. RESL analysis resulted in 63 operational taxonomic units (OTUs). This study expands our scant knowledge of anopheline species in the Yanomami and Pantanal regions. At least 18 species of Anophelinae mosquitoes were found in these study areas. Additional studies are now required to determine the species that transmit Plasmodium spp. in these regions.
Asunto(s)
Anopheles/genética , Mosquitos Vectores/genética , Plasmodium/parasitología , Animales , Brasil/epidemiología , Vectores de Enfermedades , Malaria/transmisión , Mosquitos Vectores/metabolismo , Plasmodium/genética , Especificidad de la EspecieRESUMEN
Apicomplexa is a phylum of parasitic protozoa; among them are the order Haemosporida, vector-borne parasites that include those that cause malaria (genus Plasmodium). Most Apicomplexa species have a non-photosynthetic plastid or apicoplast. Given its unique metabolic pathways, this organelle is considered a target for malaria therapeutics. Regardless of its importance, there is a paucity of complete apicoplast genome data hindering comparative studies. Here, the Haemoproteus (Haemoproteus) columbae apicoplast genome (lineage HAECOL1) was obtained using next-generation sequencing. This genome was included in a comparative analysis with other plastids. This 29.8 kb circular genome shares the same structure found in Plasmodium parasites. It is A + T rich (87.7%), comparable but at the higher end of A + T content observed in Plasmodium species (85.5-87.2%). As expected, considering its high A + T content, the synonymous codon usage (RSCU) and the effective number of codons (ENc) showed a moderate codon bias. Several apicoplast genes have a phylogenetic signal. However, unlike mitochondrial genes, single-gene phylogenies have low support in haemosporidian clades that diverged recently. The H. columbae apicoplast genome suggests that the apicoplast function may be conserved across Haemosporida. This parasite could be a model to study this organelle in a non-mammalian system.
Asunto(s)
Apicoplastos/genética , Haemosporida/citología , Filogenia , Plasmodium/parasitologíaRESUMEN
INTRODUCTION: Tissue-resident memory T cells (TRM cells) are powerful mediators of protracted adaptive immunity to infection in peripheral organs. Harnessing TRM cells through vaccination hence promises unprecedented potential for protection against infection. A paramount example of this is malaria, a major infectious disease for which immunity through traditional vaccination strategies remains challenging. Liver TRM cells appear to be highly protective against malaria, and recent developments in our knowledge of the biology of these cells have defined promising, novel strategies for their induction. AREAS COVERED: Here, we describe the path that led to the discovery of TRM cells and discuss the importance of liver TRM cells in immunity against Plasmodium spp. infection; we summarize current knowledge on TRM cell biology and discuss the current state and potential of TRM-based vaccination against malaria. EXPERT OPINION: TRM based vaccination has emerged as a promising means to achieve efficient protection against malaria. Recent advances provide a solid basis for continuing the development of this area of research. Deeper understanding of the mechanisms that mediate TRM formation and maintenance and identification of immunogenic and protective target epitopes suitable for human vaccination remain the main challenges for translation of these discoveries.
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Vacunas contra la Malaria/administración & dosificación , Malaria/prevención & control , Plasmodium/inmunología , Animales , Humanos , Memoria Inmunológica/inmunología , Hígado/inmunología , Malaria/inmunología , Malaria/parasitología , Vacunas contra la Malaria/inmunología , Plasmodium/parasitología , Linfocitos T/inmunología , VacunaciónRESUMEN
New antimalarial therapeutics are needed to ensure that malaria cases continue to be driven down, as both emerging parasite resistance to frontline chemotherapies and mosquito resistance to current insecticides threaten control programmes. Plasmodium, the apicomplexan parasite responsible for malaria, causes disease pathology through repeated cycles of invasion and replication within host erythrocytes (the asexual cycle). Antimalarial drugs primarily target this cycle, seeking to reduce parasite burden within the host as fast as possible and to supress recrudescence for as long as possible. Intense phenotypic drug screening efforts have identified a number of promising new antimalarial molecules. Particularly important is the identification of compounds with new modes of action within the parasite to combat existing drug resistance and suitable for formulation of efficacious combination therapies. Here we detail the antimalarial properties of DDD01034957-a novel antimalarial molecule which is fast-acting and potent against drug resistant strains in vitro, shows activity in vivo, and possesses a resistance mechanism linked to the membrane transporter PfABCI3. These data support further medicinal chemistry lead-optimization of DDD01034957 as a novel antimalarial chemical class and provide new insights to further reduce in vivo metabolic clearance.
Asunto(s)
Antimaláricos/farmacología , Resistencia a Medicamentos/efectos de los fármacos , Malaria/tratamiento farmacológico , Plasmodium falciparum/efectos de los fármacos , Animales , Antimaláricos/química , Eritrocitos/parasitología , Interacciones Huésped-Parásitos/efectos de los fármacos , Humanos , Concentración 50 Inhibidora , Malaria/parasitología , Ratones , Estructura Molecular , Plasmodium/efectos de los fármacos , Plasmodium/parasitología , Plasmodium berghei/efectos de los fármacos , Plasmodium berghei/parasitología , Plasmodium falciparum/fisiología , Especificidad de la EspecieRESUMEN
Introduction: Despite decades of research into the development of a vaccine to combat the malaria parasite, a highly efficacious malaria vaccine is not yet available. Different whole parasite-based vaccine approaches, including deliberate Plasmodium infection and drug cure (IDC), have been evaluated in pre-clinical and early phase clinical trials. The advantage of whole parasite vaccines is that they induce immune responses against multiple parasite antigens, thus lowering the impact of antigenic diversity. Deliberate Plasmodium IDC, as a vaccine approach, involves administering infectious, live parasites in combination with an anti-malarial drug, which controls the infection and enables induction of protective immune responses.
Asunto(s)
Vacunas contra la Malaria/administración & dosificación , Malaria/prevención & control , Plasmodium/inmunología , Animales , Antígenos de Protozoos/inmunología , Antimaláricos/administración & dosificación , Humanos , Malaria/inmunología , Malaria/parasitología , Vacunas contra la Malaria/inmunología , Plasmodium/parasitologíaRESUMEN
BACKGROUND: Malaria remains a major global health problem with a need for improved field-usable diagnostic tests. We have developed a portable, low-cost digital microscope scanner, capable of both brightfield and fluorescence imaging. Here, we used the instrument to digitize blood smears, and applied deep learning (DL) algorithms to detect Plasmodium falciparum parasites. METHODS: Thin blood smears (n = 125) were collected from patients with microscopy-confirmed P. falciparum infections in rural Tanzania, prior to and after initiation of artemisinin-based combination therapy. The samples were stained using the 4',6-diamidino-2-phenylindole fluorogen and digitized using the prototype microscope scanner. Two DL algorithms were trained to detect malaria parasites in the samples, and results compared to the visual assessment of both the digitized samples, and the Giemsa-stained thick smears. RESULTS: Detection of P. falciparum parasites in the digitized thin blood smears was possible both by visual assessment and by DL-based analysis with a strong correlation in results (r = 0.99, p < 0.01). A moderately strong correlation was observed between the DL-based thin smear analysis and the visual thick smear-analysis (r = 0.74, p < 0.01). Low levels of parasites were detected by DL-based analysis on day three following treatment initiation, but a small number of fluorescent signals were detected also in microscopy-negative samples. CONCLUSION: Quantification of P. falciparum parasites in DAPI-stained thin smears is feasible using DL-supported, point-of-care digital microscopy, with a high correlation to visual assessment of samples. Fluorescent signals from artefacts in samples with low infection levels represented the main challenge for the digital analysis, thus highlighting the importance of minimizing sample contaminations. The proposed method could support malaria diagnostics and monitoring of treatment response through automated quantification of parasitaemia and is likely to be applicable also for diagnostics of other Plasmodium species and other infectious diseases.
Asunto(s)
Pruebas Diagnósticas de Rutina/instrumentación , Pruebas Diagnósticas de Rutina/métodos , Malaria Falciparum/diagnóstico , Adulto , Colorantes Azulados , Recolección de Muestras de Sangre/métodos , Aprendizaje Profundo , Fluorescencia , Humanos , Malaria/parasitología , Malaria Falciparum/parasitología , Microscopía Fluorescente , Parasitemia/diagnóstico , Plasmodium/parasitología , Plasmodium falciparum/patogenicidad , Pruebas en el Punto de AtenciónRESUMEN
Malaria continues to be one of the top infectious agents contributing to morbidity and mortality in sub-Saharan Africa. Annually, Botswana accounts only for a small proportion of cases (<<1%). Despite significantly reduced incidence rate, the country still experiences sporadic outbreaks that hamper the goal of malaria elimination. This review evaluated previous and current biological factors that impact malaria in Botswana, specifically focussing on the vectors, the parasite and the host. This was accomplished via a literature review evaluating these variables in Botswana. Current literature suggests that Anopheles arabiensis is the main malaria vector in the country. Several other potential vectors have been found widely distributed throughout Botswana in high numbers, yet remain largely unstudied with regards to their contribution to the country's malaria burden. We also report the most up to date list of all Anopheles species that have been found in Botswana. Plasmodium falciparum is responsible for the vast majority of symptomatic malaria in the country and some drug resistance markers have been documented for this species. Plasmodium vivax has been reported in asymptomatic subjects, even though a large proportion of the Botswana population appears to be Duffy antigen negative. Very little is known about the true distribution of P. vivax and no point of care testing infrastructure for this species exists in Botswana, making it difficult to tailor treatment to address possible recrudescence or relapse. Due to a genetically diverse population with a substantial Khoisan contribution into the Bantu genetic background, several phenotypes that potentially impact prevalence and severity of malaria exist within the country. These include sickle cell trait, Glucose-6-Phosphate Dehydrogenase deficiency, and Duffy negativity. This review highlights the information that currently exists on malaria in Botswana. It also postulates that a comprehensive understanding of these aforementioned biological factors may help to explain malaria persistence in Botswana.
Asunto(s)
Anopheles/parasitología , Factores Biológicos , Malaria/tratamiento farmacológico , Malaria/epidemiología , Malaria/parasitología , Plasmodium/efectos de los fármacos , Plasmodium/parasitología , Anemia de Células Falciformes/parasitología , Animales , Botswana/epidemiología , Resistencia a Medicamentos , Sistema del Grupo Sanguíneo Duffy , Deficiencia de Glucosafosfato Deshidrogenasa/parasitología , Interacciones Huésped-Parásitos , Genética Humana , Humanos , Mosquitos Vectores/parasitologíaRESUMEN
Globally, Nigeria contributes the greatest proportion of the malaria disease burden. She currently bears the heaviest malaria burden (25% cases) and (19% deaths). Malaria is caused by Plasmodium parasites transmitted by female Anopheles mosquitoes however, a higher parasite biomass (99%) is found in man while only one (1%) is found in mosquitoes. Lending credence to this is the outcome of investigations carried out in Gboko and Otukpo Local Government Areas (LGAs); in which more humans (36.8%) had the malaria parasites than the anthropophagic female Anopheles (0.5%). Control efforts focused on mosquitoes are undermined by the actions or inactions of humans. Nigeria needs to self-audit her role in sustaining the heaviest burden of a preventable, curable disease that can also be eliminated. She can only ignore this imperative at her own peril.
Asunto(s)
Anopheles/parasitología , Malaria/epidemiología , Mosquitos Vectores , Animales , Femenino , Humanos , Malaria/transmisión , Nigeria/epidemiología , Plasmodium/parasitologíaRESUMEN
Myxozoans of the family Ceratomyxidae are common coelozoic parasites of marine, anadromous, and freshwater fish, and may also be found, less frequently, parasitizing the tissue of these hosts. The diversity and ecology of the freshwater species of the genus Ceratomyxa have been poorly investigated, leading to a knowledge gap that restricts the understanding of the distribution and prevalence of this group of parasites. In the present study, parasites were found inside vermiform plasmodia, characterised by oscillatory movements in the characiform species Hemiodus unimaculatus. The crescent-shaped and elongated spores, perpendicular to the suture line, have a mean length of 28.9 ± 2.7 µm and width of 2.6 ± 0.1 µm, with two symmetrical oval polar capsules, 1.9 ± 0.3 µm in length and 1.7 ± 0.2 µm in width, containing polar filaments with three or four coils, located near the central suture, with symmetrical lateral elongations 14.3 ± 1.1 µm in length and binucleate amoeboid sporoplasm. The integrated comparative analysis of the morphological characteristics and partial SSU rRNA sequences supported the identification of a new species of coelozoic Ceratomyxa, found in the gallbladder of H. unimaculatus, from the Tocantins basin, in the municipalities of Estreito and Imperatriz in eastern Brazilian Amazonia.The new species was denominated Ceratomyxa fonsecai n. sp.
Asunto(s)
Characiformes/parasitología , Enfermedades de los Peces/parasitología , Myxozoa/fisiología , Enfermedades Parasitarias en Animales/parasitología , Plasmodium/parasitología , Animales , Brasil , Agua Dulce/parasitología , Vesícula Biliar/parasitología , Myxozoa/clasificación , Myxozoa/citología , Myxozoa/genética , Filogenia , Plasmodium/fisiologíaRESUMEN
Introduction: Malaria is one of the most prevalent human infections worldwide with over 40% of the world's population living in malaria-endemic areas. In the absence of an effective vaccine, emergence of drug-resistant strains requires urgent drug development. Current methods applied to drug target validation, a crucial step in drug discovery, possess limitations in malaria. These constraints require the development of techniques capable of simplifying the validation of Plasmodial targets.Areas covered: The authors review the current state of the art in techniques used to validate drug targets in malaria, including our contribution - the protein interference assay (PIA) - as an additional tool in rapid in vivo target validation.Expert opinion: Each technique in this review has advantages and disadvantages, implying that future validation efforts should not focus on a single approach, but integrate multiple approaches. PIA is a significant addition to the current toolset of antimalarial validation. Validation of aspartate metabolism as a druggable pathway provided proof of concept of how oligomeric interfaces can be exploited to control specific activity in vivo. PIA has the potential to be applied not only to other enzymes/pathways of the malaria parasite but could, in principle, be extrapolated to other infectious diseases.
Asunto(s)
Antimaláricos/farmacología , Descubrimiento de Drogas , Malaria/tratamiento farmacológico , Animales , Desarrollo de Medicamentos , Humanos , Malaria/parasitología , Plasmodium/aislamiento & purificación , Plasmodium/parasitología , Estudios de Validación como AsuntoRESUMEN
The SAS6-like (SAS6L) protein, a truncated paralogue of the ubiquitous basal body/centriole protein SAS6, has been characterised recently as a flagellum protein in trypanosomatids, but associated with the conoid in apicomplexan Toxoplasma. The conoid has been suggested to derive from flagella parts, but is thought to have been lost from some apicomplexans including the malaria-causing genus Plasmodium. Presence of SAS6L in Plasmodium, therefore, suggested a possible role in flagella assembly in male gametes, the only flagellated stage. Here, we have studied the expression and role of SAS6L throughout the Plasmodium life cycle using the rodent malaria model P. berghei. Contrary to a hypothesised role in flagella, SAS6L was absent during gamete flagellum formation. Instead, SAS6L was restricted to the apical complex in ookinetes and sporozoites, the extracellular invasive stages that develop within the mosquito vector. In these stages SAS6L forms an apical ring, as we show is also the case in Toxoplasma tachyzoites. The SAS6L ring was not apparent in blood-stage invasive merozoites, indicating that the apical complex is differentiated between the different invasive forms. Overall this study indicates that a conoid-associated apical complex protein and ring structure is persistent in Plasmodium in a stage-specific manner.
Asunto(s)
Cuerpos Basales/metabolismo , Mosquitos Vectores/metabolismo , Mosquitos Vectores/parasitología , Plasmodium/metabolismo , Plasmodium/parasitología , Proteínas Protozoarias/metabolismo , Animales , Cuerpos Basales/parasitología , Femenino , Flagelos/metabolismo , Flagelos/parasitología , Estadios del Ciclo de Vida/fisiología , Malaria/metabolismo , Malaria/parasitología , Merozoítos/metabolismo , Ratones , Esporozoítos/metabolismo , Toxoplasma/metabolismo , Toxoplasma/parasitologíaRESUMEN
Nos últimos anos, a incidência de malária no Brasil vem reduzido significativamente, particularmente, em virtude das medidas de controle. Neste novo cenário, faz-se necessário identificar e tratar a malária submicroscópica, uma vez que estes indivíduos constituem fonte de infecção para o mosquito vetor. Neste contexto, nosso grupo de pesquisa vem aprimorando o diagnóstico molecular de malária e, recentemente, padronizou uma reação em cadeia da polimerase em tempo real (RT-PCR), altamente sensível, para a detecção dealvos não ribossomais (Pvr47 e Pfr364) dos plasmódios. Baseado nestes achados, o objetivo do presente trabalho foi investigar a malária subpatente em tribos indígenas de povos Ianomâmis, onde as baixas parasitemias parecem ser frequentes. A população de estudo foi constituída de indivíduos pertencentes a cinco aldeias ianomâmis do Polo Base Marari, estado do Amazonas. O estudo envolveu dois cortes transversais, sendo realizados nos meses de setembro (primeiro corte transversal) e novembro (segundo corte transversal)de 2014. Foram incluídos no estudo um total de 914 indígenas, com cerca de 1590 amostras de sangue coletadas em papel de filtro. Para o diagnóstico molecular de malária, quatro diferentes protocolos de PCR foram utilizados, sendo três baseados em alvos ribossomais(18S rRNA) e um em alvos não ribossomais (Pvr47/Pfr364) dos plasmódios.
Os resultados aqui obtidos permitiram demonstrar que os alvos Pvr47/Pfr364 foram os mais sensíveis para o diagnóstico de malária submicroscópica, embora não se mostraram adequados para o diagnóstico de espécie. Dentre os protocolos baseados no gene 18S rRNA aqui utilizados(Nested-PCR, RT-Mangold e RT-Rougemont), a Nested-PCR (método molecular dereferência) se mostrou mais apropriada para o diagnóstico específico das infecções maláricas submicroscópicas. Em conjunto, este estudo de infecção malárica em populações ianomâmis permitiu demonstrar que: (i) enquanto 0,9% das amostras foram positivas pelamicroscopia ótica (MO), diagnóstico de rotina, os protocolos moleculares identificaram 7,8% de postividade; (ii) P. vivax foi a espécie predominante, seguido do P. malariae e P. falciparum em proporções similares; (iii) a positividade por malária diminuiu com a idade(crianças>adolescentes>adultos) e foi influenciada pelas variações sazonais(setembro>novembro); (iv) a prevalência de malária variou significativamente nas diferentes aldeias, sugerindo que a doença não está homogeneamente distribuída na área de estudo. Espera-se que os resultados aqui obtidos possam contribuir para o direcionamento e monitoração de medidas de controle em reservas indígenas, bem como estimar a real incidência de malária nas áreas sob vigilância epidemiológica.
Asunto(s)
Masculino , Femenino , Humanos , Malaria/diagnóstico , Plasmodium/parasitología , Reacción en Cadena de la PolimerasaRESUMEN
INTRODUÇÃO: A malária é uma das doenças infecciosas de maior incidência e que mais leva a óbito no mundo. Os medicamentos disponíveis são capazes de combater o parasita no ciclo intraeritrocítico, no entanto há cepas resistentes ao tratamento com quinolinas e temisininas. Além disso, os medicamentos em uso clínico não eliminam as formas sexuadas do parasita, responsáveis pela transmissão, nem os hipnozoítos, fase hepática latente causadora das recidivas da doença. Em virtude disso, é necessário identificar novos fármacos antimaláricos. Dentre as classes de moléculas com potencial terapêutico antimalárico, os complexos com metais de transição se destacam como possíveis candidatos...
Asunto(s)
Humanos , Malaria/diagnóstico , Malaria/epidemiología , Malaria/prevención & control , Malaria/transmisión , Plasmodium/crecimiento & desarrollo , Plasmodium/inmunología , Plasmodium/microbiología , Plasmodium/parasitología , Plasmodium/patogenicidadRESUMEN
The field of nanotechnology involves an array of different areas of expertize with the application of innovative products in Medicine, Engineering, and to a less extent to Veterinary Medicine. In our opinion, more research is needed, in special to Animal Parasitology, to develop state of the art products to solve old problems. Livestock, pets and wildlife may benefit from products in nanoscale, such as vaccines, target recombinant proteins, or new drug candidates. Thus, we want to give some food for thought to drive scientific programs into nanotechnology, creating a safer environment to animals and humans...
Asunto(s)
Animales , Nanotecnología/historia , Nanotecnología/tendencias , Parasitología/tendencias , Leishmania/parasitología , Plasmodium/parasitologíaRESUMEN
In this study, an automatic malaria parasite detector is proposed to perceive the malaria-infected erythrocytes in a blood smear image and to separate parasites from the infected erythrocytes. The detector hence can verify whether a patient is infected with malaria. It could more objectively and efficiently help a doctor in diagnosing malaria. The experimental results show that the proposed method can provide impressive performance in segmenting the malaria-infected erythrocytes and the parasites from a blood smear image taken under a microscope. This paper also presents a weighted Sobel operation to compute the image gradient. The experimental results demonstrates that the weighted Sobel operation can provide more clear-cut and thinner object contours in object segmentation.
Asunto(s)
Eritrocitos/parasitología , Pruebas Hematológicas/instrumentación , Procesamiento de Imagen Asistido por Computador/instrumentación , Malaria/diagnóstico , Plasmodium/parasitología , Algoritmos , Humanos , MicroscopíaRESUMEN
The impact of haematozoan infection on host fitness has received substantial attention since Hamilton and Zuk posited that parasites are important drivers of sexual selection. However, short-term studies testing the assumption that these parasites consistently reduce host fitness in the wild have produced contradictory results. To address this complex issue, we conducted a long-term study examining the relationship between naturally occurring infection with Haemoproteus and Plasmodium, and lifetime reproductive success and survival of Mountain White-crowned Sparrows. Specifically, we tested the hypothesis that birds infected with haematozoan parasites have reduced survival (as determined by overwinter return rates) and reproductive success. Contrary to expectation, there was no relationship between Haemoproteus and Plasmodium infection and reproduction or survival in males, nor was there a relationship between Plasmodium infection and reproduction in females. Interestingly, Haemoproteus-infected females had significantly higher overwinter return rates and these females fledged more than twice as many chicks during their lifetimes as did uninfected females. We discuss the impact of parasitic infections on host fitness in light of these findings and suggest that, in the case of less virulent pathogens, investment in excessive immune defence may decrease lifetime reproduction.
Asunto(s)
Enfermedades de las Aves/parasitología , Haemosporida/parasitología , Interacciones Huésped-Parásitos , Malaria Aviar/parasitología , Reproducción , Gorriones/parasitología , Animales , Femenino , Haemosporida/fisiología , Masculino , Plasmodium/parasitología , Plasmodium/fisiologíaRESUMEN
Although parasitic organisms are found worldwide, the relative importance of host specificity and geographic isolation for parasite speciation has been explored in only a few systems. Here, we study Plasmodium parasites known to infect Asian nonhuman primates, a monophyletic group that includes the lineage leading to the human parasite Plasmodium vivax and several species used as laboratory models in malaria research. We analyze the available data together with new samples from three sympatric primate species from Borneo: The Bornean orangutan and the long-tailed and the pig-tailed macaques. We find several species of malaria parasites, including three putatively new species in this biodiversity hotspot. Among those newly discovered lineages, we report two sympatric parasites in orangutans. We find no differences in the sets of malaria species infecting each macaque species indicating that these species show no host specificity. Finally, phylogenetic analysis of these data suggests that the malaria parasites infecting Southeast Asian macaques and their relatives are speciating three to four times more rapidly than those with other mammalian hosts such as lemurs and African apes. We estimate that these events took place in approximately a 3-4-Ma period. Based on the genetic and phenotypic diversity of the macaque malarias, we hypothesize that the diversification of this group of parasites has been facilitated by the diversity, geographic distributions, and demographic histories of their primate hosts.
Asunto(s)
Malaria/parasitología , Plasmodium/genética , Plasmodium/patogenicidad , Primates/parasitología , Animales , Macaca/parasitología , Filogenia , Plasmodium/clasificación , Plasmodium/parasitología , Plasmodium vivax/clasificación , Plasmodium vivax/genética , Plasmodium vivax/patogenicidad , PongoRESUMEN
OBJECTIVE: To determine the sensitivity of a real time polymerase chain reaction (PCR) for malaria diagnosis and to compare its accuracy with microscopy and an antigen based rapid diagnostic test (OptiMal). STUDY DESIGN: Cross-sectional analytical study. PLACE AND DURATION OF STUDY: Military Hospital, Armed Forces Institute of Transfusion and Armed Forces Institute of Pathology, Rawalpindi, from July to December 2011. METHODOLOGY: Venous blood samples of 300 clinically suspected patients of malaria were tested for malaria parasite by microscopy and OptiMal; and malaria parasite index was calculated for the positive samples. Plasmodium genus specific real time PCR was performed on all specimens, targeting small subunit rRNA gene. Diagnostic accuracy of three tests was compared and cost analysis was done. RESULTS: Out of 300 patients, malaria parasite was detected in 110, 106 and 123 patients by microscopy, OptiMAL and PCR respectively. Real time PCR was 100% sensitive while microscopy and OptiMal had sensitivity of 89.4% and 86.2% respectively. All methods were 100% specific. The cost per test was calculated to be 0.2, 2.75 and 3.30 US$ by microscopy, OptiMal and PCR respectively, excluding the once capital cost on PCR equipment. CONCLUSION: Genus specific real time PCR for the diagnosis of malaria was successfully established as a highly sensitive and affordable technology that should be incorporated in the diagnostic algorithm in this country.
Asunto(s)
Pruebas Diagnósticas de Rutina/métodos , Malaria/diagnóstico , Microscopía/métodos , Plasmodium/aislamiento & purificación , Reacción en Cadena en Tiempo Real de la Polimerasa/métodos , Adolescente , Costos y Análisis de Costo , Estudios Transversales , Pruebas Diagnósticas de Rutina/economía , Femenino , Genes de ARNr/genética , Humanos , Malaria/sangre , Malaria/parasitología , Masculino , Microscopía/economía , Plasmodium/genética , Plasmodium/parasitología , Reacción en Cadena en Tiempo Real de la Polimerasa/economía , Sensibilidad y Especificidad , Factores de TiempoRESUMEN
OBJECTIVE: The aim of this study was to test the diagnostic performances of Cyscope®mini and Paracheck-Pf® for Plasmodium falciparum relative to microscopy. SUBJECTS AND METHODS: 209 children aged 6 months to 12 years presenting with symptoms suggestive of malaria were enrolled at the University College Hospital, Ibadan, Nigeria, within a period of 6 months. Malaria parasites were identified in capillary blood samples using Cyscope®mini (parasite DNA-based fluorescence microscope) and Paracheck-Pf® (an HRP-II-based test) with microscopy of Giemsa-stained thick blood films as reference gold standard. The overall performances were calculated using OpenEpi version 2.3 statistical package. 209 samples were performed for Cyscope®mini and light microscopy while 140 samples were done by Paracheck-Pf®. RESULTS: The prevalence of malaria parasitaemia by light microscopy was 22.0% (46/209), while those of Cyscope®mini and Paracheck-Pf® were 85.2% (178/209) and 32.1% (45/140), respectively. Parasite density ranged from 40 to 203,883/µl. Cyscope®mini and Paracheck-Pf® had sensitivities of 91.3 and 86.21%, respectively. The respective specificities were 16.56 and 81.98% for Cyscope®mini and Paracheck-Pf® with diagnostic accuracies of 33.01 and 82.86%. The diagnostic performances of the two rapid diagnostic tests were significantly different. CONCLUSION: Paracheck-Pf® performed better than Cyscope®mini for diagnosis of falciparum malaria and will be a good diagnostic tool for field studies.
Asunto(s)
Pruebas Diagnósticas de Rutina/métodos , Malaria/diagnóstico , Parasitemia/diagnóstico , Plasmodium/aislamiento & purificación , Niño , Preescolar , ADN Protozoario , Femenino , Fiebre/parasitología , Humanos , Lactante , Malaria/epidemiología , Malaria/parasitología , Masculino , Nigeria/epidemiología , Parasitemia/epidemiología , Parasitemia/parasitología , Plasmodium/parasitología , Prevalencia , Sensibilidad y Especificidad , Factores de TiempoRESUMEN
A malária é uma doença que provoca um enorme impacto em todo mundo e muitos esforços tem sido feitos na tentativa de eliminar esta doença há séculos. O desenvolvimento de uma vacina eficaz contra esta doença se tornou prioridade para muitos grupos de pesquisa, entretanto apenas um antígeno apresentou resultados promissores em ensaios clínicos de fase III. O processo de identificação de candidatos promissores para comporem uma vacina é muito laborioso e demanda um tempo muito grande, principalmente devido à biologia complexa destes parasitos intracelulares. Identificar proteínas nesses tipos de patógenos intracelulares é um grande desafio e requer a análise de diferentes fatores ao mesmo tempo. Um bom candidato a antígeno deve possuir características que façam com que a proteína ou pelo menos parte dela, entre em contato com o sistema imune do hospedeiro em algum momento do ciclo de vida do parasito e que este contato seja capaz de gerar uma resposta imune capaz de neutralizar o parasito e acabar com a infecção. As proteínas secretadas/exportadas se encaixam perfeitamente nessas características e foi justamente com o objetivo de identificá-las que foi desenvolvida uma estratégia automática integrando diferentes programas para buscar estas proteínas. Dessa forma, o proteoma predito de 5 espécies diferentes do gênero Plasmodium foi submetidas à análise de três programas que procuram por características importantes para proteínas exportadas/secretadas nesse gênero. O peptídeo sinal foi investigado utilizando o SignalP, um script em Perl foi desenvolvido para buscar um motivo que é crucial para a exportação de algumas proteínas (PEXEL) e os domínios transmembrana foram buscados utilizando o TMHMM. Algumas proteínas selecionadas foram submetidas à predição de epitopos de células B. Com esta abordagem foi possível identificar algumas famílias de proteínas que já são conhecidas como proteínas exportadas, como Rifin e Stevor, o que mostra que esta abordagem pode ser uma ferramenta útil na identificação de novos prováveis alvos para o desenvolvimento de uma vacina eficaz. Utilizando esta metodologia, esperamos contribuir para aumentar o número de proteínas em testes para formulação de um antígeno que seja capaz de ajudar no controle e erradicação desta doença que causa tantos prejuízos para a humanidade.