Caracterización molecular del dominio de la hélice del gen k13 de Plasmodium falciparum en muestras de comunidades nativas de Condorcanqui, Amazonas, Perú / Molecular characterization of the Plasmodium falciparum k13 gene helix domain in samples from native communities of Condorcanqui, Amazonas, Perú

Introducción. La resistencia de Plasmodium falciparum a diferentes fármacos antipalúdicos es un obstáculo para eliminar la enfermedad. El genotipo resistente de P. falciparum a la artemisinina puede evaluarse examinando los polimorfismos en el dominio de la hélice del gen Pfk13. La Organización Mundial de la Salud recomienda utilizar estas mutaciones como marcadores moleculares para detectar la resistencia a la artemisinina en países donde la malaria por P. falciparum es endémica. Objetivo. Identificar mutaciones relacionadas con la resistencia a artemisinina presentes en el dominio de la hélice del gen k13 de P. falciparum. Materiales y métodos. Mediante la detección pasiva de casos, se recolectaron 51 muestras positivas por microscopía para Plasmodium, provenientes de seis comunidades del distrito de Río Santiago en Condorcanqui, Amazonas. Se realizó la confirmación molecular de la especie mediante PCR en tiempo real y el dominio de la hélice del gen Pfk13 se amplificó y secuenció por electroforesis capilar. Las secuencias obtenidas se compararon con la cepa de referencia 3D7 de fenotipo silvestre. Resultados. Se confirmó un total de 51 muestras positivas para P. falciparum, provenientes de las comunidades de Ayambis, Chapiza, Palometa, Muchinguis, Alianza Progreso y Caterpiza. Después del alineamiento de las secuencias de ADN, se determinó que las muestras no presentaron mutaciones asociadas con resistencia en el gen K13. Discusión. Los resultados obtenidos son coherentes con estudios similares realizados en otros países de Sudamérica, incluyendo Perú. Estos datos proporcionan una línea base para la vigilancia molecular de resistencia a artemisinina en la región Amazonas y refuerzan la eficacia de la terapia combinada con artemisinina en esta área.

Introduction. Resistance of Plasmodium falciparum to different antimalarial drugs is an obstacle to disease elimination. The artemisinin-resistant genotype of P. falciparum can be assessed by examining polymorphisms in the helix domain of the Pfk13 gene. The World Health Organization recommends these mutations as molecular markers to detect artemisinin-resistant in countries where P. falciparum malaria is endemic. Objective. To identify artemisinin resistance-related mutations present in the helix domain of the P. falciparum k13 gene. Materials and methods. We collected a total of 51 samples through passive case detection, positive for Plasmodium by microscopy, from six communities in the district of Río Santiago in Condorcanqui, Amazonas. Molecular species confirmation was performed by real-time PCR and Pfk13 helix domain was amplified and sequenced by capillary electrophoresis. The obtained sequences were compared with the wild type 3D7 reference strain. Results. A total of 51 positive samples were confirmed for P. falciparum from the communities of Ayambis, Chapiza, Palometa, Muchinguis, Alianza Progreso and Caterpiza. DNA sequences alignment showed the absence of resistance-associated mutations in the k13 gene of the collected samples. Discussion. The obtained results are consistent with similar studies conducted in other South American countries, including Perú, so these data provide a baseline for artemisinin- resistance molecular surveillance in the Amazon region and reinforce the efficacy of artemisinin-based combination therapy in this area.

Fixation of pfcrt chloroquine resistance alleles in Plasmodium falciparum clinical isolates collected from unrest tribal agencies of Pakistan / Fixação de alelos de resistência à cloroquina pfcrt em isolados clínicos de Plasmodium falciparum coletados de agitações de agências tribais do Paquistão

Abstract Plasmodium falciparum resistance to Chloroquine (CQ) is a significant cause of mortality and morbidity worldwide. There is a paucity of documented data on the prevalence of CQ-resistant mutant haplotypes of Pfcrt and Pfmdr1 genes from malaria-endemic war effected Federally Administered Tribal Areas of Pakistan. The objective of this study was to investigate the prevalence of P. falciparum CQ-resistance in this area. Clinical isolates were collected between May 2017 and May 2018 from North Waziristan and South Waziristan agencies of Federally Administrated Trial Area. Subsequently, Giemsa-stained blood smears were examined to detect Plasmodium falciparum. Extraction of malarial DNA was done from microscopy positive P. falciparum samples, and P. falciparum infections were confirmed by nested PCR (targeting Plasmodium small subunit ribosomal ribonucleic acid (ssrRNA) genes). All PCR confirmed P. falciparum samples were sequenced by pyrosequencing to find out mutation in Pfcrt gene at codon K76T and in pfmdr1 at codons N86Y, Y184F, N1042D, and D1246Y. Out of 121 microscopies positive P. falciparum cases, 109 samples were positive for P. falciparum by nested PCR. Pfcrt K76T mutation was found in 96% of isolates, Pfmdr1 N86Y mutation was observed in 20%, and 11% harboured Y184F mutation. All samples were wild type for Pfmdr1 codon N1042D and D1246Y. In the FATA, Pakistan, the frequency of resistant allele 76T remained high despite the removal of CQ. However, current findings of the study suggest complete fixation of P. falciparum CQ-resistant genotype in the study area.

Resumo A resistência do Plasmodium falciparum à cloroquina (CQ) é uma causa significativa de mortalidade e morbidade em todo o mundo. Há uma escassez de dados documentados sobre a prevalência de haplótipos mutantes CQ-resistentes dos genes Pfcrt e Pfmdr1 da guerra endêmica da malária em áreas tribais administradas pelo governo federal do Paquistão. O objetivo deste estudo foi investigar a prevalência de resistência a CQ de P. falciparum nesta área. Isolados clínicos foram coletados entre maio de 2017 e maio de 2018 nas agências do Waziristão do Norte e do Waziristão do Sul da Área de Ensaio Administrada Federalmente. Posteriormente, esfregaços de sangue corados com Giemsa foram examinados para detectar Plasmodium falciparum. A extração do DNA da malária foi feita a partir de amostras de P. falciparum positivas para microscopia, e as infecções por P. falciparum foram confirmadas por nested PCR (visando genes de ácido ribonucleico ribossômico de subunidade pequena de Plasmodium (ssrRNA)). Todas as amostras de P. falciparum confirmadas por PCR foram sequenciadas por pirosequenciamento para descobrir a mutação no gene Pfcrt no códon K76T e em pfmdr1 nos códons N86Y, Y184F, N1042D e D1246Y. De 121 microscopias de casos positivos de P. falciparum, 109 amostras foram positivas para P. falciparum por nested PCR. A mutação Pfcrt K76T foi encontrada em 96% dos isolados, a mutação Pfmdr1 N86Y foi observada em 20% e 11% abrigou a mutação Y184F. Todas as amostras eram do tipo selvagem para o códon N1042D e D1246Y de Pfmdr1. No FATA, Paquistão, a frequência do alelo resistente 76T permaneceu alta apesar da remoção de CQ. No entanto, as descobertas atuais do estudo sugerem a fixação completa do genótipo resistente a CQ de P. falciparum na área de estudo.

Fixation of pfcrt chloroquine resistance alleles in Plasmodium falciparum clinical isolates collected from unrest tribal agencies of Pakistan / Fixação de alelos de resistência à cloroquina pfcrt em isolados clínicos de Plasmodium falciparum coletados de agitações de agências tribais do Paquistão

Plasmodium falciparum resistance to Chloroquine (CQ) is a significant cause of mortality and morbidity worldwide. There is a paucity of documented data on the prevalence of CQ-resistant mutant haplotypes of Pfcrt and Pfmdr1 genes from malaria-endemic war effected Federally Administered Tribal Areas of Pakistan. The objective of this study was to investigate the prevalence of P. falciparum CQ-resistance in this area. Clinical isolates were collected between May 2017 and May 2018 from North Waziristan and South Waziristan agencies of Federally Administrated Trial Area. Subsequently, Giemsa-stained blood smears were examined to detect Plasmodium falciparum. Extraction of malarial DNA was done from microscopy positive P. falciparum samples, and P. falciparum infections were confirmed by nested PCR (targeting Plasmodium small subunit ribosomal ribonucleic acid (ssrRNA) genes). All PCR confirmed P. falciparum samples were sequenced by pyrosequencing to find out mutation in Pfcrt gene at codon K76T and in pfmdr1 at codons N86Y, Y184F, N1042D, and D1246Y. Out of 121 microscopies positive P. falciparum cases, 109 samples were positive for P. falciparum by nested PCR. Pfcrt K76T mutation was found in 96% of isolates, Pfmdr1 N86Y mutation was observed in 20%, and 11% harboured Y184F mutation. All samples were wild type for Pfmdr1 codon N1042D and D1246Y. In the FATA, Pakistan, the frequency of resistant allele 76T remained high despite the removal of CQ. However, current findings of the study suggest complete fixation of P. falciparum CQ‑resistant genotype in the study area.

A resistência do Plasmodium falciparum à cloroquina (CQ) é uma causa significativa de mortalidade e morbidade em todo o mundo. Há uma escassez de dados documentados sobre a prevalência de haplótipos mutantes CQ-resistentes dos genes Pfcrt e Pfmdr1 da guerra endêmica da malária em áreas tribais administradas pelo governo federal do Paquistão. O objetivo deste estudo foi investigar a prevalência de resistência a CQ de P. falciparum nesta área. Isolados clínicos foram coletados entre maio de 2017 e maio de 2018 nas agências do Waziristão do Norte e do Waziristão do Sul da Área de Ensaio Administrada Federalmente. Posteriormente, esfregaços de sangue corados com Giemsa foram examinados para detectar Plasmodium falciparum. A extração do DNA da malária foi feita a partir de amostras de P. falciparum positivas para microscopia, e as infecções por P. falciparum foram confirmadas por nested PCR (visando genes de ácido ribonucleico ribossômico de subunidade pequena de Plasmodium (ssrRNA)). Todas as amostras de P. falciparum confirmadas por PCR foram sequenciadas por pirosequenciamento para descobrir a mutação no gene Pfcrt no códon K76T e em pfmdr1 nos códons N86Y, Y184F, N1042D e D1246Y. De 121 microscopias de casos positivos de P. falciparum, 109 amostras foram positivas para P. falciparum por nested PCR. A mutação Pfcrt K76T foi encontrada em 96% dos isolados, a mutação Pfmdr1 N86Y foi observada em 20% e 11% abrigou a mutação Y184F. Todas as amostras eram do tipo selvagem para o códon N1042D e D1246Y de Pfmdr1. No FATA, Paquistão, a frequência do alelo resistente 76T permaneceu alta apesar da remoção de CQ. No entanto, as descobertas atuais do estudo sugerem a fixação completa do genótipo resistente a CQ de P. falciparum na área de estudo.

Malaria en la región eco-epidemiológica del Caribe Colombiano, 1960-2019 / Malaria in the eco-epidemiological region of the Colombian Caribbean, 1960-2019

La malaria en Colombia tiene un comportamiento heterogéneo y variable, entre las regiones. Para establecer su comportamiento epidemiológico en la región del Caribe colombiano entre 1960 y 2019 se realizó un estudio observacional, descriptivo y retrospectivo a partir de registros del Ministerio de Salud y otras fuentes secundarias. Se definieron variables epidemiológicas y se elaboraron medidas de frecuencia y tendencia central. Se registraron 155 096 casos. Las décadas con mayor número de casos fueron 1990-1999 (20,5%) y 1980-1989 (18,9%). El promedio de casos por década fue de 25 849,3. Los índices parasitarios más elevados se registraron en 1970 (3,3 por 1000 habitantes) y 1981 (3,9 por 1000 habitantes). La especie Plasmodium vivax fue la más frecuente y la mayoría de la carga por grupos de edad se registró en menores de 29 años, entre 2010-2019. La malaria presentó un patrón endemo-epidémico de baja y muy baja intensidad de transmisión, con una tendencia al descenso.

Malaria has a heterogeneous and variable behavior among Colombian regions. In order to establish its epidemiological behavior in the Colombian Caribbean region between 1960 and 2019, we carried out an observational, descriptive and retrospective study based on records from the Ministry of Health and other secondary sources. We defined epidemiological variables and used measures of frequency and central tendency. A total of 155,096 cases were registered. The decades with the highest number of cases were 1990-1999 (20.5%) and 1980-1989 (18.9%). The average number of cases per decade was 25,849.3. The highest parasite rates were recorded in 1970 (3.3 per 1000 population) and 1981 (3.9 per 1000 population). Plasmodium vivax was the most frequent species and most of the burden by age group was found in people under 29 years of age, between 2010-2019. Malaria showed an endemic-epidemic pattern of low and very low transmission intensity, with a decreasing trend.

Malaria importada en población pediátrica de Alicante, España (1994-2019) / Imported malaria in children in Alicante, Spain (1994-2019)

Introducción. En los últimos años ha aumentado la malaria importada en niños, en quienes la enfermedad es potencialmente grave y mortal. Objetivo. Describir la incidencia y características clínico-epidemiológicas de niños con diagnóstico de conmalaria en Alicante, España, en los últimos años. Materiales y métodos. Se hizo un estudio observacional y retrospectivo de los casos de malaria en menores de 15 años, diagnosticados en el Hospital General Universitario de Alicante desde 1994 hasta 2019. Resultados. Se registraron 24 casos. El número de casos pasó de dos en el primer quinquenio a 11 en el último. La mediana de edad fue de 6 años (rango intercuartílico: 3 a 8). El 91,6 % procedía de África subsahariana. Los niños nacidos en España de padres inmigrantes que viajan a una zona endémica para visitar a familiares y amigos (Visiting Friends and Relatives) representaron el 62,5 % (n=15) y solo consta que recibiera quimioprofilaxis antipalúdica un paciente (6,7 %). Los signos clínicos más frecuentes fueron fiebre (86,9 %), hepatoesplenomegalia (70,8 %) y anemia (70,8 %). Plasmodium falciparum fue la especie más frecuentemente identificada (83,3 %; n=20). El tratamiento más empleado fue la combinación de dihidroartemisina y piperaquina por vía oral (41,6 %, n=10), con evolución favorable en todos los casos. Conclusiones. Los casos de paludismo infantil importado están aumentando en los últimos años. Las manifestaciones clínicas son inespecíficas en estos niños, por lo que es importante que los profesionales conozcan la enfermedad y tengan un alto índice de sospecha para iniciar el tratamiento precoz. Además, deben tomarse las medidas preventivas adecuadas antes de un viaje.

Introduction: In recent years there has been an increase in imported malaria among children in whom it is a potentially serious and fatal disease. Objective: To describe the incidence and the clinical and epidemiological characteristics of malaria in children diagnosed in Alicante, Spain, over a 26-year period. Materials and methods: We conducted an observational retrospective study of malaria in children aged under 15 years diagnosed at the Alicante General University Hospital from 1994 to 2019. Results: Twenty-four cases were registered over the study period. The frequency of cases increased from 2 over the first five years to 11 in the last five years. The median age of the children was 6 years (interquartile range: 3-8); 91.6% came from sub-Saharan Africa. Over half (n=15, 62.5%) were children born in Spain to immigrant parents visiting friends and relatives (VFR); just one (6.7%) had received antimalarial chemoprophylaxis. The most frequent clinical signs were fever (86.9%), hepatosplenomegaly (70.8%), and anemia (70.8%). Plasmodium falciparum was the most frequently identified species (83.3%, n=20). The most common treatment was oral piperaquine/dihydroartemisinin (41.6%, n=10) with favorable outcomes in all cases. Conclusions: Imported childhood malaria shows an increasing incidence and a nonspecific clinical presentation. Professional awareness of this disease and a high degree of clinical suspicion are needed for the early initiation of treatment. Pre-travel preventive measures should be promoted when appropriate.

Prevalencia de malaria gestacional en Ecuador / Prevalence of gestational malaria in Ecuador

Introducción. La malaria gestacional, definida como la presencia de Plasmodium spp. en sangre periférica materna o el hallazgo del parásito en la placenta, es considerada un importante problema de salud pública en las regiones tropicales y subtropicales. Objetivo. Determinar la frecuencia de casos de malaria gestacional diagnosticados en Ecuador entre 2015 y 2018. Materiales y métodos. Se hizo un estudio descriptivo, retrospectivo y transversal. Resultados. Se determinaron 46 casos de malaria gestacional en el período evaluado, 25 por Plasmodium falciparum y 21 por Plasmodium vivax, siendo el 2018 el año con más casos. En cuanto a las variables de edad y trimestre de gestación, prevalecieron en el grupo de 20 a 29 años (46 %) y en el segundo trimestre (37 %). Solo se observó una diferencia significativa entre los casos por año y la especie parasitaria. Conclusión. La malaria gestacional en Ecuador ha aumentado en los últimos cinco años, por lo que es importante informar a las mujeres en estado de gravidez sobre las medidas preventivas para evitar el contagio con el parásito, dadas las graves consecuencias que conlleva para ellas y sus hijos.

Introduction: Gestational malaria, defined as the presence of Plasmodium spp. in maternal peripheral blood or in the placenta, is considered an important public health problem in tropical and subtropical regions. Objective: To determine the frequency of gestational malaria cases diagnosed in Ecuador between 2015 and 2018. Materials and methods: We conducted a descriptive, retrospective, and cross-sectional study. Results: There were 46 cases of gestational malaria between 2015 and 2018: 25 caused by Plasmodium falciparum and 21 by Plasmodium vivax. The year with the most cases in this period was 2018. The age group most affected was 20 to 29 years old with 21 cases (46%). Prevalence was found to be highest in the second trimester of pregnancy with 17 cases (37%). A significant difference was only observed between cases per year and parasitic species. Conclusion: The prevalence of gestational malaria in Ecuador increased in the last five years. Therefore, it is important to inform pregnant women about preventive measures to avoid infection given its serious consequences both for the mother and her unborn child.

Sistemas de expresión de proteínas recombinantes para el análisis funcional de antígenos de Plasmodium falciparum y Plasmodium vivax: una revisión / Recombinant Protein Expression Systems for Functional Analysis of Plasmodium falciparum and Plasmodium vivax Antigens: A Review / Sistemas de expressão de proteínas recombinantes para o analise funcional de antígenos de Plasmodium falciparum e Plasmodium vivax: uma revisão

Introducción: Para diseñar vacunas es necesario comprender la función de los antígenos de Plasmodium spp. in-volucrados en la invasión a células hospederas. Diferentes investigaciones han generado proteínas recombinantes utilizando sistemas de expresión heterólogos y así han obtenido moléculas semejantes a las nativas. Con estos avances se desarrollan estrategias que bloquean la infección de estos patógenos. Objetivo: Describir las características y los aspectos metodológicos más importantes de los sistemas de expresión de las proteínas recombinantes en estudios funcionales de Plasmodium spp. Metodología: Revisión descriptiva de estudios publicados en Pubmed, Science Direct, Embase y Medline, entre 2010 y 2020, que incluyeran sistemas recombinantes en células de Escherichia coli, de mamífero y sistemas libres de células, para estudios funcionales de antígenos de Plasmodium falciparum y Plasmodium vivax. Se revisaron 70 artículos originales y 58 cumplieron con los criterios establecidos. Resultados: Obtener proteínas recombinantes mediante un sistema procariota, de mayor rendimiento y bajo costo, ha permitido estudiar un número importante de antígenos. Los sistemas con células de mamífero y libres de células, que permiten modificaciones postraduccionales y plegamiento adecuado de moléculas, se usan para producir librerías de antígenos con estructura conformacional similar a la nativa. Conclusión: El estudio de los antígenos de Plasmodium spp. implicados en la infección y desarrollo de células diana requiere una adecuada selección del método de producción recombinante. El refinamiento de procesos de expresión en sistemas procariotas, eucariotas e in vitro, mediante ingeniería genética y cultivo celular, permitirá mejores rendimientos y menor costo.

Introduction: Understanding the function of Plasmodium spp. Antigens involved in invasion of host cells is necessary to design vaccines. Different studies have generated recombinant proteins using heterologous expression systems, obtaining molecules similar to native ones. These advances are es-sential to develop strategies that block the infection of these pathogens. Objective: Describe the most important characteristics and methodological aspects of recombinant protein expression systems in functional studies of Plasmodium spp. Methodology: Descriptive review of studies published in Pubmed, Science Direct, Embase and Medline, between 2010 and 2020, that included recombinant systems in Escherichia coli cells, mam-malian and cell-free, for functional studies of Plasmodium falciparum and Plasmodium vivax antigens. 70 original articles were reviewed, 58 met the established criteria. Results: Obtaining recombinant proteins by means of a prokaryotic system, with higher performance and low cost, has allowed functional studies of a significant number of antigens. Mammalian cell and cell free systems, which allow for post-translational modifications and adequate folding of molecules, are used to produce antigen libraries with native-like conformational structure. Conclusion:Plasmodium spp. antigen study involved in infection and development in target cells, re-quires adequate selection of the recombinant production method. The refinement of expression pro-cesses in prokaryotic, eukaryotic and in vitro systems, through genetic engineering and cell culture, will allow better yields and lower cost

Introdução: Para desenvolver vacinas, é necessário entender a função dos antígenos de Plasmodium spp. envolvidos na invasão das células hospedeiras. As pesquisas têm gerado proteínas recombinan-tes utilizando sistemas de expressão heterólogos para obter moléculas similares às nativas. Com estes avanços, estratégias que bloqueiam a infecção destes patógenos estão sendo desenvolvidas. Objetivo: Descrever as características mais importantes e aspectos metodológicos dos sistemas de expressão de proteínas recombinantes em estudos funcionais de Plasmodium spp. Metodologia: Revisão descritiva dos estudos publicados em Pubmed, Science Direct, Embase e Medline, entre 2010 e 2020, que incluíram sistemas recombinantes em células de Escherichia coli, de mamífero e sistemas livres de células, para estudos funcionais dos antígenos de Plasmodium fal-ciparum e Plasmodium vivax. Setenta artigos originais foram revisados e 58 preenchiam os critérios estabelecidos. Resultado: A obtenção de proteínas recombinantes usando um sistema procariótico, com maior rendimento e baixo custo, permitiu o estudo de um número significativo de antígenos. Sistemas de células mamíferas e sem células, que permitem modificações pós-tradução e dobramento adequado das moléculas, são usados para produzir bibliotecas de antígenos com uma estrutura semelhante à nativa. Conclusão: O estudo dos antígenos Plasmodium spp. envolvidos na infecção e no desenvolvimento das células-alvo requer uma seleção adequada do método de produção recombinante. O refinamento dos processos de expressão em sistemas procarióticos, eucarióticos e in vitro, através da engenharia genética e da cultura celular, permitirá melhores rendimentos e menores custos.

Mechanism of action of glycyrrhizin against Plasmodium falciparum

Extracts of the plant Glycyrrhiza glabra (licorice) are used in traditional medicine to treat malaria. The main active components are the saponin glycyrrhizin (GLR) and its active metabolite glycyrrhetinic acid (GA) which both display activities against Plasmodium falciparum. We have identified three main mechanisms at the origin of their anti-plasmodial activity: (i) drug-induced disorganisation of membrane lipid rafts, (ii) blockade of the alarmin protein HMGB1 and (iii) potential inhibition of the detoxifying enzyme glyoxalase 1 (GLO-1) considered as an important drug target for malaria. Our analysis shed light on the mechanism of action of GLR against P. falciparum.

Estudo da prevalência de deleções dos genes pfhrp2 e pfhrp3 de Plasmodium falciparum no município de Barcelos, Região do Médio Rio Negro, Amazonas / Study of the prevalence of pfhrp2 and pfhrp3 gene deletions of Plasmodium falciparum in the municipality of Barcelos, Middle Rio Negro Region, Amazonas

Introdução: Os testes rápidos para diagnóstico de malária (RDTs) mais usados se baseiam na identificação do antígeno HRP2 de P. falciparum. O antígeno HRP3, também presente no P. falciparum é um análogo estrutural do antígeno HRP2 e por isso pode ter reação cruzada com o HRP2 nesses testes. O antígeno HRP2 é expresso pelo gene pfhrp2, enquanto o antígeno HRP3 é expresso pelo gene pfhrp3. São crescentes os estudos que relatam deleções naturais dos genes pfhrp2 e pfhrp3 em P. falciparum em diversos países endêmicos para malária, inclusive em países que fazem fronteira com o Brasil. No país foi descrita a presença de isolados mutantes circulando na região da Bacia do Rio Amazonas. A confirmação da presença de parasitos com essas deleções em áreas endêmicas do país é fundamental, visto que indivíduos infectados por P. falciparum com deleção dos genes pfhrp2/3 podem apresentar resultados falso negativo no RDT. O objetivo deste estudo foi investigar a prevalência de deleções dos genes pfhrp2/3 em amostras de pacientes infectados com P. falciparum de área endêmica de malária no Brasil no período de 2003 a 2016, e bem como identificar a população acometida e a diferenciação clínica entre indivíduos infectados por parasitos com deleção e parasitos sem deleção. Métodos: Foram analisadas amostras procedentes do biorrepositório do Laboratório de Doenças Parasitárias do Instituto Oswaldo Cruz coletadas no período de 2003 a 2016 no município de Barcelos (AM) de indivíduos sintomáticos e assintomáticos infectados por P. falciparum. O diagnóstico de Plasmodium spp. foi realizado através da detecção do gene 18S de rRNA por PCR. O controle de qualidade do DNA foi realizado pela amplificação de msp1 e msp2. A detecção dos genes pfhrp2 e pfhrp3 foi realizada de acordo com protocolos publicados e bem padronizados pela OMS. Resultados: Foram selecionadas 82 amostras, 28 amostras apresentaram deleção exclusiva do gene pfhrp2, 19, deleção exclusiva do gene pfhrp3 e 15 dupla deleção. Infecção assintomática ocorreu com mais frequência em indivíduos mais velhos e com grande número episódios prévios da doença. A chance de um indivíduo assintomático estar infectado por um parasito com dupla deleção foi maior do que entre os sintomáticos. Conclusão: A alta prevalência de parasitos com deleções de pfhrp2/3 encontrada no município de Barcelos é motivo de preocupação e mostram a necessidade de se implementar um programa de vigilância para monitorar e mapear deleções de pfhrp2/3 nesta área e em outros locais da região amazônica. O padrão clínico pode estar associado às deleções encontradas nos parasitos infectantes.

Introduction: The most used rapid tests for the diagnosis of malaria are based on the identification of the P. falciparum antigen HRP2. The HRP3 antigen, also present in P. falciparum, is a structural analogue of the HRP2 antigen and, therefore, may cross-react with HRP2 in these tests. The HRP2 antigen is expressed by the pfhrp2 gene, while the HRP3 antigen is expressed by the pfhrp3 gene. Studies reporting natural deletions of the pfhrp2 and pfhrp3 genes in P. falciparum are growing in several countries endemic for malaria, including countries bordering Brazil. In the country, the presence of mutant isolates circulating in the Amazon River Basin region has been described. Confirmation of the presence of parasites with these deletions in other endemic areas of the country is fundamental, since individuals infected with P. falciparum with deletion of the pfhrp2/3 genes can present false negative result in the RDT. The objective of this study was to investigate the deletions of the pfhrp2/3 genes in samples from patients infected with P. falciparum in an endemic area for malaria in Brazil from 2003 to 2016, in order to describe the prevalence of the gene (s) ( s) deleted in the studied endemic area; as well as to identify the affected population and the clinical differentiation between individuals infected by parasites with deletion and parasites without deletion. Methods: Samples from the biorepository of the Laboratory of Parasitic Diseases of the Oswaldo Cruz Institute collected from 2003 to 2016 in the municipality of Barcelos (AM) from symptomatic and asymptomatic individuals infected with P. falciparum were analyzed. The diagnosis of Plasmodium spp. was performed by detecting the 18S rRNA gene by PCR. DNA quality control was performed by amplifying msp1 and msp2. The detection of the pfhrp2 and pfhrp3 genes was carried out according to published protocols and well standardized by the WHO. Results: 82 samples were selected, 28 samples showed exclusive deletion of the pfhrp2 gene, 19, exclusive deletion of the pfhrp3 gene and 15 double deletion. Asymptomatic infection occurred more frequently in older individuals and with a large number of previous episodes of the disease. The chance of an asymptomatic individual being infected by a parasite with double deletion was greater than among symptomatic individuals. Conclusion: The high prevalence of parasites with deletions of fhrp2/3 found in the municipality of Barcelos is a cause for concern and shows the need to implement a surveillance program to monitor and map deletions of pfhrp2 / 3 in this area and elsewhere in the Amazon region. The clinical pattern may be associated with the deletions found in the infectious parasites.

Quinolinotriazole antiplasmodials via click chemistry: synthesis and in vitro studies of 7-Chloroquinoline-based compounds

Malaria is nowadays one of the most serious health concerns in a global scale and, although there is an evident increase in research studies in this area, pointed by the vast number of hits and leads, it still appears as a recurrent topic every year due to the drug resistance shown by the parasite exposing the urgent need to develop new antimalarial medications. In this work, 38 molecules were synthesized via copper(I)-catalyzed alkyne-azide cycloaddition (CuAAC) or "click" chemistry, following different routes to produce 2 different organic azides, obtained from a 4,7 dicholoquinoline, reacted with 19 different commercially available terminal alkynes. All those new compounds were evaluated for their in vitro activity against the chloroquine resistant malaria parasite Plasmodium falciparum (W2). The cytotoxicity evaluation was accomplished using Hep G2 cells and SI index was calculated for every molecule. Some of the quinoline derivatives have shown high antimalarial activity, with IC50 values in the range of 1.72-8.66 µM, low cytotoxicity, with CC50>1000 µM and selectivity index (SI) in the range of 20-100, with some compounds showing SI>800. Therefore, the quinolinotriazole hybrids could be considered a very important step on the development of new antimalarial drugs

Detection of antimalarial drug resistance polymorphisms in Plasmodium falciparum chloroquine resistance transporter and Plasmodium falciparum multidrug resistance 1 genes of Plasmodium falciparum found in Kano State, Nigeria

Objectives: In 2018, malaria claimed an estimated 380,000 lives in African region, with Nigeria accounting for 24.0% (91,368) of malaria deaths from the region. Mutations in Plasmodium falciparum chloroquine resistance transporter (Pfcrt) and P. falciparum multidrug resistance 1 (Pfmdr-1) genes had reduced the effective use of artemisinin combination therapy through the development of resistance to these antimalarial agents. Our study set out to determine the antimalarial drug resistance polymorphisms in Pfcrt and Pfmdr-1 genes of P. falciparum isolates among patients in Kano State, Nigeria. Material and Methods: Malaria positive samples were collected across the three senatorial districts of Kano State. The samples were amplified using nested polymerase chain reaction to detect the Pfcrt and Pfmdr-1 genes. The amplicons were sequenced and bioinformatic analysis was done using CLC Sequence viewer 8.0 and BioEdit sequence alignment editor to detect the single-nucleotide polymorphisms. Results: In the Pfcrt gene, CVIET haplotype was seen in 26.2% of the samples while only two samples showed the 86Y mutation in the Pfmdr-1 gene. All the 86Y mutations and majority of the CVIET haplotypes were detected in the patients from rural settings where some of them noted that they consumed modern and traditional (herbs) antimalarial agents. One sample was observed to have the CVIET haplotype and N86Y mutation while the other five CVIET haplotypes were seen in five separate samples. A new mutation V62A was found in the Pfmdr-1 gene as observed in one of the sample. Conclusion: It is imperative to ensure the rational use of the right antimalarial agents and employ continuous resistance surveillance/mapping to ensure synergy in malaria containment and elimination strategies.

Diversidad genética de plasmodium falciparum / Genetic diversity of Plasmodium falciparum

La diversidad genética le confiere a Plasmodium falciparum la capacidad de evadir la respuesta inmune del hospedero y producir variantes resistentes a medicamentos y a vacunas. Diferentes autores han documentado la existencia de cepas o clones de P. falciparum, cuya diversidad genética se ha confirmado a través de distintos ensayos de PCR (reacción en cadena de la polimerasa). El objetivo fue describir la diversidad genética de P. falciparum. MÉTODOS: Para la revisión narrativa se hizo una búsqueda de literatura publicada, que incluyó libros y artículos científicos originales, verificando el tema, así como reportes técnicos. Los documentos se consultaron entre agosto y diciembre de 2019 a través del acceso en Internet y bibliotecas del Academic Search Complete del gestor de búsquedas Medline, Science Direct, Scopus, Redalyc y Psicodoc. RESULTADOS: Se identificaron secuencias polimórficas útiles como marcadores genéticos de las poblaciones de P. falciparum, con los genes de las proteínas de superficie del merozoíto 1 y 2 (MSP-1, MSP-2) y el gen de la proteína rica en glutamato (GLURP), que producen variantes resistentes a medicamentos y a vacunas. DISCUSIÓN: Los hallazgos en las diferentes regiones estudiadas permiten concluir que la diversidad genética, la multiplicidad de infección y la dinámica en el tiempo de las infecciones por P. falciparum se ven afectadas por el grado de endemicidad de la malaria en cada país.

Actividad antiparasitaria in vitro de plantas de la medicina tradicional Tacana sobre Plasmodium faciparum a través del método fluorométrico-SYBR GreenI / In vitro antiparasitic activity from plants of the Tacana traditional medicine on Plasmodiumfaciparum through thefluorometric method-SYBR GreenI

INTRODUCCIÓN: la presencia de compuestos activos en las plantas las posiciona como una fuente alternativa para el descubrimiento de nuevos fármacos. OBJETIVO: realizar la bioprospección de plantas utilizadas en la medicina tradicional tacana frente a cultivos de Plasmodium falciparum. MÉTODOS: se obtuvieron extractos por maceración en etanol a temperatura ambiente, de 31 órganos colectados de 23 plantas, estos fueron evaluados sobre cultivos asincrónicos de la cepa de Plasmodium falciparum resistente a la Cloroquina (FCR3). A los extractos que mostraron actividad antiplasmódica (CI50<20µg/mL), se evaluó la citotoxicidad (DL50) frente a células HeLa y se calculó el índice de selectividad (IS=DL50/CI50). Los extractos que dieron resultados IS>5, fueron seleccionados como promisorios. RESULTADOS: se obtuvieron 3 plantas muy activas (CI50<10µg/mL); 2 moderadamente activas (10µg/mL20µg/mL). De las 9 plantas que presentaron actividad, solo 2 plantas presentaron IS>5. CONCLUSIONES: incorporar los conocimientos del uso tradicional para realizar las evaluaciones biológicas es de mucha ayuda en la selección de plantas con efectos antiplasmódicos.

INTRODUCTION: the presence of active compounds in plants, converts them as an alternative to find new drugs. OBJECTIVE: carry out the bioprospecting of plants used in Tacana traditional medicine against Plasmodium falciparum cultures. METHODS: from the 31 collected organs of 23 plants, raw extracts were obtained by ethanolic maceration at room temperature and these were evaluated on asynchronic cultures of the strain Plasmodium falciparum resistant to Chloroquine (FCR3). The active extracts (IC50<20µg/mL), were evaluated for cytotoxicity (LD50) against HeLa cells and the Selectivity Index (IS=DL50/IC50) was calculated. The extracts that sowed IS>5were selected as promising. RESULTS: a total of 3 species were very active (IC50<10µg/mL); 2 were moderately active (10µg/mL20µg/mL). From the 9 active plants only 2 presented IS>5. CONCLUSIONS: incorporating the traditional knowledge to carry out biological evaluations is very helpful in the selection of plants with antiplasmodial effects.

Production of glycosylphosphatidylinositol-anchored proteins for vaccines and directed binding of immunoliposomes to specific cell types

Liposomes are highly useful carriers for delivering drugs or antigens. The association of glycosylphosphatidylinositol (GPI)-anchored proteins to liposomes potentially enhances the immunogenic effect of vaccine antigens by increasing their surface concentration. Furthermore, the introduction of a universal immunoglobulin-binding domain can make liposomes targetable to virtually any desired receptor for which antibodies exist. Methods: We developed a system for the production of recombinant proteins with GPI anchors and histidine tags and Strep-tags for simplified purification from cells. This system was applied to i) the green fluorescent protein (GFP) as a reporter, ii) the promising Plasmodium falciparum vaccine antigen PfRH5 and iii) a doubled immunoglobulin Fc-binding domain termed ZZ from protein A of Staphylococcus aureus. As the GPI-attachment domain, the C-terminus of murine CD14 was used. After the recovery of these three recombinant proteins from Chinese hamster ovary (CHO) cells and association with liposomes, their vaccine potential and ability to target the CD4 receptor on lymphocytes in ex vivo conditions were tested. Results: Upon immunization in mice, the PfRH5-GPI-loaded liposomes generated antibody titers of 103 to 104, and showed a 45% inhibitory effect on in vitro growth at an IgG concentration of 600 µg/mL in P. falciparum cultures. Using GPI-anchored ZZ to couple anti-CD4 antibodies to liposomes, we created immunoliposomes with a binding efficiency of 75% to CD4+ cells in splenocytes and minimal off-target binding. Conclusions: Proteins are very effectively associated with liposomes via a GPI-anchor to form proteoliposome particles and these are useful for a variety of applications including vaccines and antibody-mediated targeting of liposomes. Importantly, the CHO-cell and GPI-tagged produced PfRH5 elicited invasion-blocking antibodies qualitatively comparable to other approaches.(AU)

Description of an automatic copulation induction system used to establish a free-mating laboratory colony of Nyssorhynchus deaneorum from Brazil

BACKGROUND Nyssorhynchus deaneorum is a potential malaria vector because it has been shown to be competent to transmit Plasmodium vivax and Plasmodium falciparum, and because it exhibits antropophilic and endophilic behaviors in some regions of the Amazon. This profile makes Ny. deaneorum a useful mosquito for experiments that model Plasmodium-vector interactions in the Amazon. OBJECTIVE Herein we describe how a free-mating colony of Ny. deaneorum has been established using an automated light stimulation system. METHODS Mosquitoes were captured in São Francisco do Guaporé, Rondônia. The F1 generation was reared until adult emergence at which point copulation was induced using an automatic copulation induction system (ACIS). FINDINGS After four generations, natural mating and oviposition began to occur without light stimulation. The number of pupae and adult mosquitoes increased from the F5 to F10 generations. The new Ny. deaneorum colony exhibited susceptibility to P. vivax. MAIN CONCLUSIONS Automated light stimulation is an effective method for establishing an Ny. deaneorum colony under laboratory conditions as it produces enough adults to create a stenogamic colony. The establishment of a stable, P. vivax-susceptible colony of Ny. deaneorum makes it possible to model parasite-vector interactions and to test novel drug therapies that target parasite development in mosquitoes.

Avances en el desarrollo de una vacuna contra la malaria por Plasmodium falciparum: una revisión de literatura / Advances in the development of vaccine against malaria by Plasmodium falciparum: a literature review / Avanços no desenvolvimento de uma vacina contra a Malária por Plasmodium falciparum: Uma revisão da literatura

Introducción. La malaria por Plasmodium falciparum es una enfermedad causante de altas tasas de morbimortalidad a nivel mundial. Diferentes candidatos a vacuna se han evaluado experimentalmente en humanos; sin embargo, no se dispone de ninguna vacuna que reduzca o elimine esta devastadora enfermedad. Objetivo. Describir en términos de diseño, respuesta inmune, eficacia protectiva y perspectivas, los principales candidatos vigentes a vacuna contra la malaria por Plasmodium falciparum, dirigidos a las fases pre-eritrocítica y eritrocítica. Metodología. Se realizó una revisión descriptiva de trabajos publicados en bases de datos PubMed, Science Direct, Embase y MedLine. Los criterios de inclusión fueron: trabajos publicados en una ventana de tiempo entre 2000 y 2019, candidatos a vacuna contra Plasmodium falciparum en estadíos pre y eritrocíticos y vigencia según la Organización Mundial de la Salud. En total, se revisaron 90 artículos originales, encontrando que 63 cumplieron con todos los criterios establecidos, mientras que 27, no cumplieron por lo menos con un criterio. Resultados. Los candidatos a vacunas vigentes incluyen diseños basados en parásitos atenuados, proteínas recombinantes, vectores virales y síntesis química. Las formulaciones contienen un número mínimo de antígenos con secuencias de aminoácidos altamente polimórficas, que inducen un aceptable perfil de inmunogenicidad, aunque una limitada eficacia protectora contra la malaria, debido a que tales regiones polimórficas son inmunodominantes, confiriendo únicamente inmunidad específica de cepa. Conclusiones. El desarrollo de una vacuna efectiva contra la malaria por Plasmodium falciparum posiblemente requiera incluir múltiples epítopes funcionalmente relevantes, del estadío pre y eritrocítico, que contengan regiones conservadas entre cepas, para lograr inducir respuestas inmunes duraderas que bloqueen la invasión del parásito a células hepáticas y eritrocitos.

Introduction. Plasmodium falciparum malaria is a disease that causes high rates of morbidity and mortality worldwide. Different vaccine candidates have been evaluated experimentally in humans; however, there is no vaccine available that reduces or eliminates this devastating disease. Objective. Describe in terms of design, immune response, protective efficacy and perspectives, the main current candidates for Plasmodium falciparum malaria vaccine aimed at the pre-erythrocytic and erythrocyte phases. Methodology. A descriptive review of works published in PubMed, Science Direct, Embase and MedLine databases was carried out. The inclusion criteria were: papers published in a time window between 2000 and 2019, candidates for vaccine against Plasmodium falciparum in pre and erythrocyte stages and validity according to the World Health Organization. In total, 90 original articles were reviewed, finding that 63 met all the established criteria, while Introduction. Plasmodium falciparum malaria is a disease that causes high rates of morbidity and mortality worldwide. Different vaccine candidates have been evaluated experimentally in humans; however, there is no vaccine available that reduces or eliminates this devastating disease. Objective. Describe in terms of design, immune response, protective efficacy and perspectives, the main current candidates for Plasmodium falciparum malaria vaccine aimed at the pre-erythrocytic and erythrocyte phases. Methodology. A descriptive review of works published in PubMed, Science Direct, Embase and MedLine databases was carried out. The inclusion criteria were: papers published in a time window between 2000 and 2019, candidates for vaccine against Plasmodium falciparum in pre and erythrocyte stages and validity according to the World Health Organization. In total, 90 original articles were reviewed, finding that 63 met all the established criteria, while 27 did not meet at least one criterion. Results. Applicants for current vaccines include designs based on attenuated parasites, recombinant proteins, viral vectors and chemical synthesis. The formulations include a minimum number of an- tigens with highly polymorphic amino acid sequences, which induce an acceptable immunogenicity profile, although a limited protective efficacy against malaria. Conclusion. The development of an effective vaccine against malaria by Plasmodium falciparum may require the inclusion of multiple functionally relevant epitopes, from the pre and erythrocyte stage, which do not contain polymorphic regions, in order to induce lasting immune responses that block the invasion of the parasite to hepatic and erythrocyte target cells.27 did not meet at least one criterion. Results. Applicants for current vaccines include designs based on attenuated parasites, recombinant proteins, viral vectors and chemical synthesis. The formulations include a minimum number of an- tigens with highly polymorphic amino acid sequences, which induce an acceptable immunogenicity profile, although a limited protective efficacy against malaria. Conclusion. The development of an effective vaccine against malaria by Plasmodium falciparum may require the inclusion of multiple functionally relevant epitopes, from the pre and erythrocyte stage, which do not contain polymorphic regions, in order to induce lasting immune responses that block the invasion of the parasite to hepatic and erythrocyte target cells.

Introdução. A malária por Plasmodium falciparum é uma doença que causa altas taxas de morbimortalidade em todo o mundo. Diferentes candidatos à vacina foram avaliados experimentalmente em humanos; no entanto, nenhuma vacina está disponível para reduzir ou eliminar esta doença devastadora. Objetivo. Descrever em termos de projeção, resposta imune, eficácia protetora e perspectivas, os principais candidatos atuais à vacina contra a malária por Plasmodium falciparum, visando às fases pré-eritrocítica e eritrocítica. Metodologia. Foi realizada uma revisão descritiva dos trabalhos publicados nas bases de dados PubMed, Science Direct, Embase e MedLine. Os critérios de inclusão foram: trabalhos publicados em uma janela temporal entre 2000 e 2019, candidatos à vacina contra Plasmodium falciparum nos estágios pré e eritrocitários e validade de acordo com a Organização Mundial da Saúde. No total, foram revisados 90 artigos originais, constatando que 63 atendiam a todos os critérios estabelecidos, enquanto 27 não atendiam pelo menos um critério. Resultados. Os candidatos atuais à vacina incluem projeções baseadas em parasitas atenuados, pro- teínas recombinantes, vetores virais e síntese química. As formulações contêm um número mínimo de antígenos com sequências de aminoácidos altamente polimórficas, que induzem um perfil de imu- nogenicidade aceitável, embora com eficácia protetora limitada contra a malária, uma vez que essas regiões polimórficas são imunodominantes, conferindo apenas imunidade específica à cepa. Conclusão. O desenvolvimento de uma vacina eficaz contra a malária por Plasmodium falciparum pode exigir a inclusão de vários epítopos funcionalmente relevantes, do estágio pré e eritrocítico, contendo regiões conservadas entre as cepas, a fim de induzir respostas imunes duradouras que permitam bloquear a invasão do parasita nas células hepáticas e eritrócitos.

Proteínas homólogas de unión a reticulocitos de Plasmodium falciparum involucradas en el proceso de invasión al eritrocito: revisión de la literatura / Plasmodium falciparum reticulocyte-binding homologous proteins involved in the process of erythrocyte invasion: literature review / Proteínas de ligação a reticulócitos de Plasmodium falciparum homólogas envolvidas no pro-cesso de invasão de eritrócitos: revisão da literatura

Introducción: la malaria es uno de los mayores retos de la salud pública mundial. Es causada principalmente por los parásitos Plasmodium falciparum y Plasmodium vivax. Durante el proceso de invasión, se encuentran involucra-das las proteínas homólogas de unión a reticulocitos de P.falciparumPfRH1, PfRH2a, PfRH2b, PfRH4 y PfRH5, que tras su unión a receptores específicos de membrana permiten la invasión del merozoíto al eritrocito. Objetivo: compilar y resumir las características moleculares y estructurales de las interacciones entre las proteínas pertenecientes a la familia de proteínas homólogas de unión a reticulocitos de P.falciparum y los receptores expre-sados en la célula del hospedero. Método: revisión descriptiva sobre las proteínas homólogas de unión a reticulocitos de P. falciparum involucradas en el proceso de invasión al eritrocito. Esta revisiónincluye literatura publicada hasta el año 2020 en bases de datos electrónicas especializadas en investigación biomédica. Se encontraron 105 documentos, de los cuales se se-leccionaron 70 y se excluyeron 11, por no presentar los criterios de inclusión, analizando un total de 59 referencias. Conclusión: la invasión del merozoíto es mediada por interacciones específicas de los ligandos de las familias EBL y PfRH. La unión de las proteínas PfRH1 y PfRH2b a sus receptores en el eritrocito da lugar a la liberación de la proteína EBL-175 que, junto con PfRH4, median la formación de una unión estrecha entre el parásito y los glóbulos rojos. Ello permite la unión de la proteína PfRH5 a la basigina y la entrada del parásito a la célula del hospedero

Introduction: Malaria is one of the world's greatest public health challenges, caused mainly by Plas-modium falciparum and Plasmodium vivax. During the invasion process, the P. falciparum reticulo-cyte-binding homologous proteins PfRH1, PfRH2a, PfRH2b, PfRH4 and PfRH5 are involved, which after binding to specific membrane receptors allow the invasion of the merozoite into the erythrocyte. Objective: To compile and summarize the molecular and structural characteristics of the interactions between proteins belonging to the P. falciparum family of reticulocyte-binding homologous proteins and the receptors expressed in the host cell. Method: Descriptive review of the P. falciparum reticulocyte-binding homologous proteins involved in the process of erythrocyte invasion. This review includes literature published until 2020 in electronic databases specialized in biomedical research. We found 105 papers, of which 70 were selected and 11 were excluded for not presenting the inclusion criteria, analyzing a total of 59 references. Conclusion: The invasion of merozoite is mediated by specific interactions of the ligands of the LBS and PfRH families. The binding of the PfRH1 and PfRH2b proteins to their receptors in the erythrocyte results in the release of the EBL-175 protein, which together with PfRH4 mediates the formation of a close bond between the parasite and the red blood cells, thus allowing the binding of the PfRH5 protein to basigin and the entry of the parasite into the host cell.

Introdução: a malária é um dos maiores desafios globais de saúde pública. É causada principalmente pelos parasitas Plasmodium falciparum e Plasmodium vivax. Durante o processo de invasão, proteínas homólogas de ligação a reticulócitos de P. falciparum PfRH1, PfRH2a, PfRH2b, PfRH4 e PfRH5 estão envolvidas, que após a ligação a receptores de membrana específicos permitem a invasão do mero-zoíta ao andritro. Objetivo: compilar e resumir as características moleculares e estruturais das interações entre as pro-teínas pertencentes à família das proteínas reticulocitárias homólogas de P. falciparum e os receptores expressos na célula hospedeira. Método: revisão descritiva das proteínas ho-mólogas de ligação a reticulócitos de P. falciparum envol-vidas no processo de invasão eritrocitária. Esta revisão inclui literatura publicada até 2020 em bases de dados eletrônicas especializadas em pesquisa biomédica. Foram encontrados 105 documentos, dos quais 70 foram selecionados e 11 excluídos por não apresentarem os critérios de inclusão, anali-sando um total de 59 referências. Conclusão: a invasão de merozoítos é mediada por interações específicas dos ligantes das famílias EBL e PfRH. A ligação das proteínas PfRH1 e PfRH2b aos seus receptores no eritrócito resulta na libe-ração da prote-ína EBL-175 que, junto com PfRH4, a mediação da formação de uma junção compacta entre o parasita e as hemácias. Isso permite a ligação da proteína PfRH5 à basigina e a entrada do parasita na célula hospedeira.

Method for rapid synchronization of different growth cycles of Plasmodium falciparum in vitro and application in differential gene expression profile of 3D7 after dihydroartemisinin treatment / 中国中药杂志

Plasmodium culture in vitro is often used as an antimalarial drug evaluation model, but the lifecycle of P. falciparum culture in vitro tends to be disordered, which affects the research and evaluation of antimalarial drug mechanism in vitro. By combining magnetic bead separation method with sorbitol synchronization method, a synchronization method was constructed to quickly acquire different lifecycles of P. falciparum and obtain large amounts of parasite with a narrow synchronization window in a short period. Furthermore, the dihydroartemisinin(DHA) was used to treat the early trophozoite phase of P. falciparum 3 D7 for 4 h. Then mRNA was extracted and RNA-seq was conducted to analyze the differential expression of mRNA after drug treatment and obtain the differential gene expression profile. Differential expression of up-regulated genes and down-regulated genes was analyzed according to the screening criteria of |log_2FC|>1 and P<0.05. There, 262 genes were up-regulated and 77 genes were down-regulated. GO functional enrichment analysis of all the differentially expressed genes showed that the enrichment items mainly included cell membrane components, transporter activity, serine/threonine kinase activity, Maurer's clefts(MCs), rhoptry, antigen variation and immune evasion. The enrichment of KEGG pathway included malaria, fatty acid metabolism and peroxisome. Protein-protein interaction(PPI) analysis showed that the down-regulated genes in the modules with high degree of association included rhoptry, myosin complex, transporter and other genes related to the important life activities of malaria invasion and immune escape; the up-regulated genes were mainly related to various toxic exportins of malaria, such as PfSBP1 of MCs. qRT-PCR was used to verify the expression level of some genes, and most of the results were the same as the sequencing results. SBP1 was significantly up-regulated, while some antigenic protein expression levels were down-regulated. Above all, key molecules of DHA therapy were mainly involved in the parasites' rhoptry, transporter, antigenic variation, plasmodium exportin. These results offer us many hints to guide the further studies on mechanism of artemisinin and provide a new way for development of new antimalarial drugs.

In vitro and in vivo antimalarial activity of the volatile oil of Cyperus articulatus (Cyperaceae)

Malaria is a disease of global tropical distribution, being endemic in more than 90 countries and responsible for about 212 million cases worldwide in 2016. To date, the strategies used to eradicate this disease have been ineffective, without specific preventive measures such as vaccines. Currently, the existing therapeutic arsenal is limited and has become ineffective against the expansion of artemisinin-resistant Plasmodium, demonstrating the need for studies that would allow the development of new compounds against this disease. In this context, we studied the volatile oil obtained from rhizomes of Cyperus articulatus (VOCA), a plant species commonly found in the Amazon region and popularly used as a therapeutic alternative for the treatment of malaria, in order to confirm its potential as an antimalarial agent by in vitro and in vivo assays. We cultured Plasmodium falciparum W2 (chloroquine-resistant) and 3D7 (chloroquine-sensitive) strains in erythrocytes and exposed them to VOCA at different concentrations in 96-well microplates. In vivo antimalarial activity was tested in BALB/c mice inoculated with approximately 106 erythrocytes infected with Plasmodium berghei. VOCA showed a high antimalarial potential against the two P. falciparum strains, with IC50 = 1.21 µg mL-1 for W2 and 2.30 µg mL-1 for 3D7. VOCA also significantly reduced the parasitemia and anemia induced by P. berghei in mice. Our results confirmed the antimalarial potential of the volatile oil of Cyperus articulatus. (AU)

Evaluación de la calidad del diagnóstico de malaria en la red local de laboratorios y en los laboratorios intermedios en el contexto de la eliminación de la enfermedad en Ecuador / Quality evaluation of malaria diagnosis in the local laboratories network and in intermediate laboratories in a setting towards the disease elimination in Ecuador

Resumen Introducción. El cumplimiento de la meta de eliminación de la malaria en Ecuador en el 2020 exige contar con la capacidad requerida para el diagnóstico microscópico ajustado a los estándares de calidad de la Organización Mundial de la Salud (OMS) y de la Organización Panamericana de la Salud (OPS) y proveer el tratamiento adecuado a los pacientes. Objetivo. Conocer la idoneidad o competencia de los microscopistas de la red pública local para el diagnóstico parasitológico de la malaria y el desempeño de los laboratorios intermedios de referencia. Materiales y métodos. Se hizo un estudio descriptivo de corte transversal a partir de la información obtenida en los talleres de evaluación de idoneidad en el diagnóstico microscópico de la red de laboratorios en las coordinaciones zonales de salud utilizando un panel de láminas para evaluar la concordancia del diagnóstico. Además, se calificó el desempeño de los laboratorios intermedios en el diagnóstico en el marco del programa de evaluación externa del desempeño. Los resultados se compararon con los obtenidos por el laboratorio supranacional de Perú. Resultados. En los 11 talleres realizados, se evaluó la idoneidad de 191 microscopistas, de los cuales 153 (80,1 %) aprobaron las pruebas. Las medianas de los indicadores fueron las siguientes: concordancia entre la detección y el resultado, 100 % (Q1- Q3: 96-100); concordancia en la especie, 100 % (Q1- Q3: 93-100); concordancia en el estadio, 93,0 % (Q1- Q3: 86-95) y concordancia en el recuento, 77 % (Q1- Q3: 71-82). En el programa de evaluación externa de desempeño, los tres laboratorios intermedios obtuvieron una concordancia del 100 % en el resultado y una del 96 % en la especie. Conclusiones. Los indicadores de competencia de la red local y de desempeño de los laboratorios intermedios alcanzaron altos estándares de calidad acordes con el proceso de entrenamiento implementado en el país.

Abstract Introduction: To reach the goal of malaria elimination in Ecuador for the year 2020, it is necessary to have a laboratory network with the capacity to perform microscopic diagnosis according to the WHO/PAHO quality standards and to provide the adequate treatment of cases. Objective: To determine the level of competence for parasitological diagnosis of the microscopists from the local public network and the performance of intermediate reference laboratories. Materials and methods: We conducted a cross-sectional study based on the information collected in workshops carried out to appraise the competence for microscopic diagnosis of the local laboratory network (zonal health coordinating offices 1 to 8) using a slide panel to evaluate diagnosis agreement, as well as the diagnostic performance of the intermediate laboratories using an external quality assessment program. The results were compared against the reference standards of the supranational laboratory in Perú. Results: We evaluated the competencies of 191 microscopists in 11 workshops and 153 (80.1%) of them were approved. The medians of the indicators were the following: concordance for parasite detection, 100% (Q1- Q3: 96-100), concordance for species identification, 100% (Q1- Q3: 93-100), and concordances for stage identification, 93.0% (Q1- Q3: 86-95) and parasite counting, 77.0% (Q1- Q3: 71-82). In the external quality assessment, the three intermediate laboratories obtained 100% in parasite detection concordance and 96% for species detection concordance. Conclusions: The results for the primary network and the performance indicators for the intermediate laboratories showed the high-quality standards of the training program implemented in the country.