Frequency of blood donation and malaria occurrence among blood donors in a tertiary hospital, Nigeria

Context: Malaria is a significant cause of morbidity and mortality in Sub-Saharan Africa (SSA). Transfusion transmitted malaria contributes significantly to the burden of malaria in SSA. The safety of blood transfusion as it relates to frequency of blood donation and malaria occurrence on the part of donors is an aspect that has not been properly investigated hence this study. Objectives: This study was conducted to assess the frequency of blood donation and occurrence of malaria among blood donors at OAUTHC, Ile-Ife. Materials and methods: This was a cross-sectional study. Ethical approval was obtained. One hundred and thirty-three consenting blood donors aged between 18-50 years were recruited for the study. Two milliliter's of blood were collected from each study participant and immediately transported to the laboratory for processing. Giemsa-stained films of the samples were viewed under the oil immersion objective of the microscope. Questionnaires were administered to the study participants to obtain relevant information. Data generated were analyzed using descriptive and inferential statistics with SPSS software version 20. The level of significance was set at p < 0.05. Results: The prevalence of malaria among the blood donors was 21.1% with the highest rate among commercial donors (33.3%) followed by family donors (12.9%) then voluntary donors (11.9%). Evaluation of the frequency of donation showed that malaria occurred more in recurring donors (77.78%) than first time donors (22.22%).

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.

Perfil de notificações de malária em gestantes de Oiapoque, Amapá / Profile of malaria reports in pregnant women from Oiapoque, Amapá / Perfil de notificaciones de malaria en gestantes de Oiapoque, Amapá

Objetivo: caracterizar as notificações de malária em gestantes no município de Oiapoque. Método: estudo documental, descritivo, retrospectivo e com abordagem quantitativa, realizado a partir de dados secundários do Sistema de Vigilância Epidemiológica da Malária em Oiapoque-Amapá, Brasil, no período de 2013 a 2017. Abordam-se as seguintes variáveis de casos autóctones de malária em gestantes: ano, mês de ocorrência, idade gestacional, espécie infectante de Plasmodium e unidade de notificação. Os dados foram apresentados e analisados mediante estatística descritiva e formulação de mapas de distribuição espacial, gerados pelo software ArcGIS. Resultados: predominaram notificações em áreas urbanas, especialmente no bairro Paraíso (74%), sendo o Plasmodium vivax o principal agente (88%), e de maior incidência entre outubro a dezembro (33%), no terceiro trimestre gestacional (35%). Conclusão: o perfil de notificações de malária em gestante desse munícipio assemelha-se a estudos anteriores nessa região quanto ao local de concentração e período de maior ocorrência. No entanto, a introdução gradativa do protozoário Plasmodium falciparum traz um alerta para a mobilização de gestores e profissionais.

Objective: to characterize the notifications of malaria in pregnant women in the municipality of Oiapoque. Method: documentary, descriptive, retrospective and quantitative study, conducted from secondary data of the Epidemiological Surveillance System of Malaria in Oiapoque-Amapá, Brazil, from 2013 to 2017. The following variables of autochthonous cases of malaria in pregnant women are addressed: year, month of occurrence, gestational age, Plasmodium infecting species and notification unit. Data were presented and analyzed using descriptive statistics and formulation of spatial distribution maps, generated by ArcGIS software. Results: notifications predominated in urban areas, especially in the Paraíso neighborhood (74%), with Plasmodium Vivax being the main agent (88%), and with a higher incidence between October and December (33%), in the third gestational quarter (35%). Conclusion: the profile of reports of malaria in pregnant women of this municipality resembles previous studies in this region, regarding the place of concentration and period of greater occurrence. However, the gradual introduction of the protozoan Plasmodium falciparum brings an alert to the mobilization of managers and professionals.

Investigação sobre a presença de Plasmodium spp. em Anophelinae (Diptera: Culicidae) do Vale do Ribeira, sudeste da Mata Atlântica, Estado de São Paulo, Brasil / Investigation of the presence of Plasmodium spp. in Anophelinae (Diptera: Culicidae) from Vale do Ribeira, southeastern Atlantic Forest, State of São Paulo, Brazil

Objetivos: Identificar espécies de anofelinos presentes na região do Vale do Ribeira, Sudeste de São Paulo, e a circulação de plasmódios por estes anofelinos. Método: Foram utilizadas armadilhas CDC com atração luminosa e armadilhas de Shannon no período que compreende das 17:00 às 22:00 horas e atração por humano protegido realizadas das 9:00 às 12:00 horas durante três dias consecutivos em seis campanhas, realizadas de setembro de 2021 a novembro de 2022. Os espécimes capturados foram identificados morfologicamente, separados por espécie e tiveram seu DNA genômico extraído em grupos de até 10 mosquitos, considerando os métodos de captura, locais, datas e horas. Os grupos de DNA genômico foram analisados utilizando tecnologia de PCR em tempo real para amplificar fragmento de 157 a 165 pares de bases da unidade 18S do DNA ribossômico, que permite identificar a presença de plasmódios. As amostras positivas foram submetidas a técnicas de PCR aninhado de fragmento do gene citocromo b do genoma mitocondrial. De oito amostras analisadas, duas foram positivas e tiveram seus amplicons sequenciados empregando tecnologia de Sanger. Resultados: Foram coletados 5.577 mosquitos classificados no gênero Kerteszia (99,62%) e gênero Anopheles (0,38%), agrupados em 811 grupos. Foram identificados oito grupos positivos para plasmódios, sendo um para Plasmodium vivax / Plasmodium simium, um para Plasmodium malariae / Plasmodium brasilianum, dois para Plasmodium falciparum e quatro grupos positivos apenas para Plasmodium spp. O sequenciamento Sanger confirmou a infecção por P. vivax / P. simium em uma amostra, e P. malariae / P. brasilianum em outra. A proporção total de anofelinos infectados por Plasmodium spp. foi 0,5% (4/811), 0,2% dos anofelinos coletados apresentavam infecção por P. falciparum (2/811), 0,1% apresentavam infecção por P. vivax (1/811) e a mesma proporção de infectados por P. malariae (1/811). A razão mínima de infecção (RMI) para Plasmodium spp. nos anofelinos coletados foi 0,125, para P. vivax foi 0,02, assim como para P. malariae e, para P. falciparum foi 0,035. As estimativas de razão entre mosquitos infectados e mosquitos coletados foram 0,007 para Plasmodium spp., 0,0002 para P. vivax, 0,0005 para P. falciparum e 0,0005 para P. malariae. A razão de infecção absoluta por P. vivax foi 0,02 em março de 2022 e 0,01 por P. falciparum em novembro de 2022 no mesmo ponto de coleta. Conclusão: Foi identificada a presença de plasmódios zoonóticos em área de reserva da Mata Atlântica do sudeste brasileiro, onde a presença de hospedeiros humanos é restrita aos moradores, turistas, trabalhadores da reserva e pesquisadores. A densidade de mosquitos infectados por P. falciparum foi maior do que a de P. vivax e P. malariae. O encontro de mosquitos, naturalmente, infectados por estas espécies de plasmódios indica a necessidade de programas de educação ambiental delineados aos frequentadores e moradores da região da reserva e do entorno. Acresce considerar a necessidade de pesquisas detalhadas sobre as taxas de Plasmodium ocorrendo na área estudada e na Mata Atlântica, com sequenciamentos dos genomas das espécies que são encontradas em localidades diversas do Brasil e América Latina.

Objectives: Identify species of anophelines present in the Vale do Ribeira region, Southeast of São Paulo, and the circulation of plasmodia by these anophelines. Method: CDC light traps and Shannon traps were used in the period from 5:00 p.m. to 10:00 p.m. and attraction by protected human carried out from 9:00 a.m. to 12:00 p.m. for three consecutive days in 6 campaigns, carried out from September 2021 to November 2022. The captured specimens were morphologically identified, separated by species, and had their genomic DNA extracted in pools of up to 10 mosquitoes, considering capture methods, locations, dates and time. By utilizing real-time PCR technology, a 157 to 165 base pairs segment of the 18S ribosomal DNA unit was amplified to identify plasmodia within the genomic DNA pools. The positive samples were submitted to nested PCR techniques of cytochrome b gene fragment of the mitochondrial genome. Of 8 samples analyzed, two were positive and had their amplicons sequenced using Sanger technology. Results: A total of 5,577 mosquitoes belonging to the genus Kerteszia (99.62%) and to the genus Anopheles (0.38%) were collected, grouped into 811 pools. Eight positive pools for plasmodia were identified, one for Plasmodium vivax / Plasmodium simium, one for Plasmodium malariae / Plasmodium. brasilianum, two for Plasmodium falciparum and four pools positive only for Plasmodium spp. Sanger sequencing confirmed P. vivax / P. simium infection in one sample, and P. malariae / P. brasilianum in the other. The total proportion of anophelines infected with Plasmodium spp. was 0.5% (4/811), 0.2% of the collected anophelines had P. falciparum infection (2/811), 0.1% had P. vivax infection (1/811) and the same proportion of infected with P. malariae (1/811). The minimum infection rate (MIR) for Plasmodium spp. in anophelines collected was 0.125, for P. vivax was 0.02, as well as for P. malariae, and for P. falciparum it was 0.035. The ratio estimates between infected and collected mosquitoes were 0.007 for Plasmodium spp., 0.0002 for P. vivax, 0.0005 for P. falciparum, and 0.0005 for P. malariae. The absolute infection ratio for P. vivax was 0.02 in March 2022 and 0.01 for P. falciparum infection in November 2022 at the same collection point. Conclusion: The presence of zoonotic plasmodia was identified in a reserve area of the Atlantic Forest in southeastern Brazil, where the presence of human hosts is restricted to residents, tourists, reserve workers and researchers. The density of mosquitoes infected with P. falciparum was higher than that of P. vivax and P. malariae. The finding of mosquitoes naturally infected by these species of plasmodia shows the need for environmental education programs designed for visitors and residents of the reserve region and surroundings. In addition, consider the need for detailed research on the rates of Plasmodium occurring in the studied area and in the Atlantic Forest, with sequencing of the genomes of the species that are found in different locations in Brazil and Latin America.

Representação social da malária na perspectiva dos garimpeiros em Boa Vista ­ Roraima / Social representation of malaria from the prespective of miners in Boa Vista ­ Roraima / Representación social de la malaria en la perspectiva de los mineros de Boa Vista ­ Roraima

Objetivo: analisar o núcleo central da representação social acerca da malária na ótica dos garimpeiros e dos indivíduos que exercem atividades laborais em região de garimpo que buscam atendimento no Pronto Atendimento Cosme e Silva em Boa Vista/RR. Método:estudo descritivo exploratório de carácter qualitativo delineado por meio da Teoria das Representações Sociais, formulada por Serge Moscovici em 1961. Foram realizadas 72 entrevistas semiestruturadas com garimpeiros. A análise dos dados ocorreu com o auxílio do software OpenEvoc 0.92 desenvolvido pelo Prof. Dr. Hugo Cristo em 2012. Resultados: foi constatado que as percepções dos garimpeiros acerca da malária está diretamente relacionada com a sintomatologia da doença, principalmente pelos traumas vivenciados devidoa ausência de serviço de saúde disponível no local de trabalho. Enquanto que, as percepções dos garimpeiros sobre o garimpo estão vinculadas a condição econômica deste grupo. Conclusão:observa-se que a busca pelo bem-estar financeiro, faz o garimpeiro se submeter às relações extremamente precárias de trabalho, incluindo a exposição ao vetor da malária.

Objective: to analyze the central nucleus of the social representation about malaria from the perspective of miners and individuals who carry out work activities in a mining region who seek care at the Cosme e Silva Emergency Room in Boa Vista/RR. Method:descriptiveexploratory study of a qualitative nature outlined through the Theory of Social Representations, formulated by Serge Moscovici in 1961. 72 semi-structured interviews were carried out with miners. Data analysis took place with the aid of the OpenEvoc 0.92 software developed by Prof. Dr. Hugo Cristo in 2012. Results:it was found that the prospectors' perceptions about malaria are directly related to the symptoms of the disease, mainly due to the traumas experienced due to the lack of health services available in the workplace. Meanwhile, the prospectors' perceptions about mining are linked to the economic condition of this group. Conclusion:it is observed that the search for financial well-being makes the prospector submit to extremely precarious work relationships, including exposure to the malaria vector.

Objetivo: analizar el núcleo central de la representación social sobre la malaria en la perspectiva de mineros y personas que ejercen actividades laborales en una región minera que buscan atención en el Servicio de Emergencia Cosme e Silva de Boa Vista/RR. Método:estudio descriptivo exploratorio de carácter cualitativo esbozado a través de la Teoría de las Representaciones Sociales, formulada por Serge Moscovici en 1961. Se realizaron 72 entrevistas semiestructuradas con mineros. El análisis de datos se llevó a cabocon la ayuda del software OpenEvoc 0.92 desarrollado por el Prof. Dr. Hugo Cristo en 2012. Resultados:se encontró que las percepciones de los prospectores sobre la malaria están directamente relacionadas con los síntomas de la enfermedad, principalmente debido a los traumas experimentados por la falta de servicios de salud disponibles en el lugar de trabajo. Por su parte, las percepciones de los buscadores sobre la minería están ligadas a la condición económica de este grupo. Conclusión: se observa que labúsqueda de bienestar económico hace que el prospector se someta a relaciones de trabajo extremadamente precarias, incluida la exposición al vector de la malaria.

Malária: A crise silenciosa em Alto Alegre, Roraima e o fantasma do garimpo na Terra Indígena Yanomami / Malaria: The Silent Crisis in Alto Alegre, Roraima and the Specter of Mining in the Yanomami Indigenous Land / Malaria: La crisissilenciosa en Alto Alegre, Roraima y el fantasma de la minería en la Tierra Indígena Yanomami

Objetivo:analisar a evolução dos casos de malária em Roraima, principalmente no município de Alto Alegre, estratificado por aglomerações por área geográfica habitada -rural, urbana e área indígena no período de 2013 a 2022. Método:Estudo ecológico do tipo série temporal baseado em dados secundários dos casos confirmados de malária em Roraima, no período de 2013 a 2022. Resultados:nesse período foram confirmados 72.828 casos de malária em Roraima, dos quais 78,0% foram por Plasmodium vivax. Além disso, a maior parte dos casos se concentrou no município de Alto Alegre, correspondendo a 41,1%. Portanto, este foi o município que mais produziu malária procedente de garimpo, apesar de existirem outros que registraram aumento da doença nesse período. Conclusão:assim, osmunicípios de Alto Alegre, Amajari, Caracaraí, Iracema e Mucajaí, juntos respondem por 77.8% de toda malária produzida em Roraima. Estes municípios fazem parte da rota do garimpo ilegal na terra indígena Yanomami.

Objective: analyze the evolution of malaria cases in Roraima, especially in the municipality of Alto Alegre, stratified by geographical areas of habitation -rural, urban, and indigenous areas, from 2013 to 2022. Method: A time series ecological study based on secondary data of confirmed malaria cases in Roraima from 2013 to 2022. Results:During this period, 72,828 cases of malaria were confirmed in Roraima, of which 78.0% were due to Plasmodium vivax. Furthermore, the majority of cases were concentrated in the municipality of Alto Alegre, accounting for 41.1%. Therefore, this was the municipality that produced the most malariafrom mining activities, despite others experiencing an increase in the disease during this period. Conclusion: Thus, the municipalities of Alto Alegre, Amajari, Caracaraí, Iracema, and Mucajaí together accounted for 77.8% of all malaria cases produced in Roraima. These municipalities are part of the illegal mining route within the Yanomami indigenous land.

Objetivo: analizar la evolución de los casos de malaria en Roraima, principalmente en el municipio de Alto Alegre, marcado por aglomeraciones por área geográfica habitada -rural, urbana, en el área indígena en el período comprendido desde 2013 hasta 2022. Método: Estudio ecológico de tipo serie temporal basado en datos secundarios de los casos confirmados de malaria en Roraima, en el periodo de 2013 hasta 2022. Resultados: Durante este periodo fueron confirmados 72.828 casos de malaria en Roraima, de los cuales 78,0% correspondieron a Plasmodium Vivax. Además, la mayor parte de los casos estaban concentrados en el municipio de Alto Alegre, correspondiendo a 41,1%. Por lo tanto, este fue el condado que más produjo malaria proveniente de la minería, a pesar de existir otros que registraron aumentos de la enfermedad durante este periodo. Conclusión: Siendo así, los condados de Alto Alegre, Amajari, Caracaraí, Iracema y Mucajaí, juntos representan el 77.8% de toda la malaria existente en Roraima. Estos condados hacen parte de la ruta de minería ilegal en tierras indígenas Yanomam.

Prevalence and seroprevalence of COVID-19 in suspected malaria during the second wave in Yaounde, Cameroon

Background. The COVID-19 pandemic has added an additional burden in countries with already fragile health systems. Our objective was to determine the prevalence and seroprevalence of COVID-19 in suspected malaria during the second wave in Yaounde. Methods. A descriptive cross-sectional study was conducted at the Jordan Medical Services for 8 weeks from April 19 to June 13, 2021, i.e., during the second wave in Cameroon. For the 86 patients with suspected malaria, nasopharyngeal and blood samples were taken for SARS-CoV-2 antigen and anti-SARS-CoV-2 IgG and IgM using the STANDARD TM Q COVID-19 Ag kit from SD BIOSENSOR, Korea, 2020 and Standard TM Q COVID 19 Ac IgG/IgM kit from SD BIOSENSOR, Korea, 2020 respectively. Confirmation of malaria was done by microscopic examination of stained blood smears. Results. Malaria was confirmed in 20.9% (18) of cases. The prevalences of COVID-19 and COVID-19/malaria co-infection were 8.1% and 0.9% respectively. Of the 25.6% (54) of patients with anti-COVID-19 IgM, no positive microscopic cases were found. On the other hand, a little more than half of the patients had IgG antibodies against COVID-19 whether they had a positive thick drop or not (56.0% (42/75) and 52.2% (71/136) respectively). Conclusion. In case of suspicion of malaria in a malaria area, it seems important to consider COVID-19 as a differential diagnosis.

Introduction. La pandémie de la COVID-19 a ajouté un fardeau supplémentaire dans les pays aux systèmes de santé déjà fragiles. Objectif : déterminer la prévalence et la séroprévalence de la COVID-19 en cas de suspicion du paludisme au cours de la deuxième vagueà Yaoundé. Méthodologie. Une étude transversale descriptive a été menée au Centre Médical le Jourdain pendant 8 semaines du 19 Avril au 13 Juin 2021 soit durant la deuxième vague au Cameroun. Pour les 86 patients avec suspicion de paludisme, des prélèvements nasopharyngé et sanguins ont été réalisés pour la recherche d'antigène du SRAS- CoV 2 et des IgG et IgM anti-SARS-CoV-2 grâce aux kits STANDARDTM Q COVID-19 Ag de SD BIOSENSOR, Corée, 2020 et StandardTM Q COVID 19 Ac IgG/IgM de SD BIOSENSOR, Corée, 2020 respectivement. La confirmation du paludisme a été faite grâce à l'examen microscopique des étalements de sang colorés. Résultats. Le paludisme était confirmé dans 20,9% (18) des cas. Les prévalences de la COVID-19 et de la coïnfection COVID19/Paludisme étaient de 8,1% et de 0,9% respectivement. Sur les 25,6% (54) des patients avec des IgM anti-COVID-19, aucun cas de microscopie positive n'a été retrouvé. Par ailleurs un peu plus de la moitié des patients avaient des anticorps IgG anti-COVID-19 qu'ils aient une goutte épaisse positive ou pas soit 56,0% (42/75) et 52,2% (71/136) respectivement. Conclusion. En cas de suspicion du paludisme en zone impaludée, il parait non négligeable de considérer la COVID-19 comme un diagnostic différentiel.

Artemisinin drug resistance and monitoring: a narrative review

Artemisinin drug resistance is one of the major reasons for malaria treatment failures in the sub-Saharan African countries where artemisinin-based combination therapy (ACT) is the first-line treatment for uncomplicated malaria. The occurrence of single nucleotide polymorphisms (SNPs) is found to correlate with antimalarial drug resistance. With artemisinin, the SNPs occurs at the Kelch 13-propeller gene locus on chromosome 13. The artemisinin drug resistance surveillance strategy involves continuous monitoring of Kelch 13-propeller biomarker to detect emergence of mutations which could herald drug resistance in the region. In this narrative review paper, we examined existing literature to bridge the knowledge gap and accentuate the importance of routine surveillance for artemisinin resistance in sub-Saharan Africa. We conducted our search on PubMed database and Google Scholar to identify peer-reviewed articles, reports, and abstracts on artemisinin drug resistance using the following keywords; 'artemisinin drug resistance', 'antimalarial drug resistance', 'artemisinin-based combination therapy', 'Kelch 13-propeller', 'K13- propeller gene', and 'K13 molecular marker'. The review provided pertinent information on artemisinin derivatives, artemisinin-based combination therapy, molecular action of artemisinin, definition of artemisinin resistance, genetic basis of artemisinin drug resistance and discovery of Kelch 13, and the importance of artemisinin resistance surveillance. Molecular surveillance can provide healthcare policy makers a forecast of impending threats to malaria treatment. This is more so when drugs are in combination therapy, for instance, molecular surveillance can give a hint that one drug is failing despite the fact that in combination, it is still apparently clinically effective.

Artemisinin drug resistance and monitoring: a narrative review

Artemisinin drug resistance is one of the major reasons for malaria treatment failures in the sub-Saharan African countries where artemisinin-based combination therapy (ACT) is the first-line treatment for uncomplicated malaria. The occurrence of single nucleotide polymorphisms (SNPs) is found to correlate with antimalarial drug resistance. With artemisinin, the SNPs occurs at the Kelch 13-propeller gene locus on chromosome 13. The artemisinin drug resistance surveillance strategy involves continuous monitoring of Kelch 13-propeller biomarker to detect emergence of mutations which could herald drug resistance in the region. In this narrative review paper, we examined existing literature to bridge the knowledge gap and accentuate the importance of routine surveillance for artemisinin resistance in sub-Saharan Africa. We conducted our search on PubMed database and Google Scholar to identify peer-reviewed articles, reports, and abstracts on artemisinin drug resistance using the following keywords; 'artemisinin drug resistance', 'antimalarial drug resistance', 'artemisinin-based combination therapy', 'Kelch 13-propeller', 'K13- propeller gene', and 'K13 molecular marker'. The review provided pertinent information on artemisinin derivatives, artemisinin-based combination therapy, molecular action of artemisinin, definition of artemisinin resistance, genetic basis of artemisinin drug resistance and discovery of Kelch 13, and the importance of artemisinin resistance surveillance. Molecular surveillance can provide healthcare policy makers a forecast of impending threats to malaria treatment. This is more so when drugs are in combination therapy, for instance, molecular surveillance can give a hint that one drug is failing despite the fact that in combination, it is still apparently clinically effective.

La résistance aux médicaments à base d'artémisinine est l'une des principales raisons des échecs du traitement du paludisme dans les pays d'Afrique subsaharienne où la polythérapie à base d'artémisinine (ACT) est le traitement de première intention du paludisme simple. L'apparition de polymorphismes mononucléotidiques (SNP) est corrélée à la résistance aux médicaments antipaludiques. Avec l'artémisinine, les SNP se produisent au locus du gène Kelch 13- propeller sur le chromosome 13. La stratégie de surveillance de la résistance aux médicaments à base d'artémisinine implique une surveillance continue du biomarqueur Kelch 13-propeller pour détecter l'émergence de mutations qui pourraient annoncer une résistance aux médicaments dans la région. Dans cet article de revue narrative, nous avons examiné la littérature existante pour combler le manque de connaissances et accentuer l'importance de la surveillance de routine de la résistance à l'artémisinine en Afrique subsaharienne. Nous avons effectué notre recherche sur la base de données PubMed et Google Scholar pour identifier des articles, des rapports et des résumés évalués par des pairs sur la résistance aux médicaments à base d'artémisinine en utilisant les mots-clés suivants; «résistance aux médicaments à base d'artémisinine¼, «résistance aux médicaments antipaludiques¼, «thérapie combinée à base d'artémisinine¼, «Kelch 13-propeller¼, «gène K13-propeller¼ et «marqueur moléculaire K13¼. L'examen a fourni des informations pertinentes sur les dérivés de l'artémisinine, la polythérapie à base d'artémisinine, l'action moléculaire de l'artémisinine, la définition de la résistance à l'artémisinine, la base génétique de la résistance aux médicaments à base d'artémisinine et la découverte de Kelch 13, ainsi que l'importance de la surveillance de la résistance à l'artémisinine. La surveillance moléculaire peut fournir aux responsables des politiques de santé une prévision des menaces imminentes pour le traitement du paludisme. C'est d'autant plus vrai lorsque les médicaments sont en thérapie combinée, par exemple, la surveillance moléculaire peut donner un indice qu'un médicament échoue malgré le fait qu'en combinaison, il est toujours apparemment cliniquement efficace.

Rectal artesunate for severe malaria, implementation research, Zambia

Objective To determine whether the positive results of a single-district pilot project focused on rectal artesunate administration at the community level in Zambia could be replicated on a larger scale. Methods In partnership with government, in 10 rural districts during 2018­2021 we: (i) trained community health volunteers to administer rectal artesunate to children with suspected severe malaria and refer them to a health facility; (ii) supported communities to establish emergency transport, food banks and emergency savings to reduce referral delays; (iii) ensured adequate drug supplies; (iv) trained health workers to treat severe malaria with injectable artesunate; and (v) monitored severe malaria cases and associated deaths via surveys, health facility data and a community monitoring system. Results Intervention communities accessed quality-assured rectal artesunate from trained community health volunteers, and follow-on treatment for severe malaria from health workers. Based on formal data from the health management information system, reported deaths from severe malaria reduced significantly from 3.1% (22/699; 95% confidence interval, CI: 2.0­4.2) to 0.5% (2/365; 95% CI: 0.0­1.1) in two demonstration districts, and from 6.2% (14/225; 95% CI: 3.6­8.8) to 0.6% (2/321; 95% CI: 0.0­1.3) in eight scale-up districts. Conclusion Despite the effects of the coronavirus disease, our results confirmed that pre-referral rectal artesunate administered by community health volunteers can be an effective intervention for severe malaria among young children. Our results strengthen the case for wider expansion of the pre-referral treatment in Zambia and elsewhere when combined with supporting interventions.

Mort in utero tardive: fréquence, facteurs associés et méthodes de déclenchement du travail à Kisangani, République Démocratique du Congo / Late fetal death: frequency, associated factors and methods of labor induction in Kisangani, Democratic Republic of Congo

La mort fœtale tardive fait référence à la mort in utéro (MIU) de survenue spontanée à partir de 22 semaines d'aménorrhée (SA), mais avant tout début du travail d'accouchement, ce qui constitue une tragédie pour la mère, les membres de la famille et du personnel soignant. La présente étude a déterminé l'ampleur, les facteurs associés et les méthodes de déclenchement artificiel du travail d'accouchement sur MIU. Méthodes : Il s'est agi d'une étude transversale descriptive, multicentrique menée dans 3 hôpitaux de Kisangani, pendant une période de 3 ans. La collecte des données était rétrospective, des cas de MIU à partir de 28 SA. Résultats : La fréquence de MIU tardive était de 6,48%. Les principaux facteurs associés étaient l'infection urinaire (35,4%), le paludisme sur grossesse (27,5%) et l'hypertension artérielle gravidique (27,5%). Le taux de participation aux consultations prénatales (CPN) n'était que de 63,5 %. Les méthodes de déclenchement artificiel du travail d'accouchement utilisées étaient le Misoprostol (42,7%), l'ocytocine (17,7%) soit les deux combinées (25%). La césarienne était indiquée à un taux de 26,4%. Conclusion : la fréquence de MIU tardive est élevée à Kisangani. L'infection urinaire, le paludisme et l'hypertension artérielle en constituaient les principaux facteurs associés. Le Misoprostol était la méthode de déclenchement du travail les plus utilisées. Un suivi régulier des CPN pourrait réduire le taux de MIU.

Comparaison des coûts du traitement du paludisme en biomédecine et en médecine traditionnelle à Niono (Mali) / Comparison of costs of treatment of malaria in biomedicine and traditional medicine in Niono (Mali)

Introduction. Au Mali, la prise en charge du paludisme se fait à travers la médecine conventionnelle et la médecine traditionnelle, mais peu d'évaluation existe sur les implications fi nancières de ces approches qui coexistent et qui sont pratiqués parfois de manière concomitante. L'objectif de cette étude était d'évaluer les coûts fi nanciers de ces deux approches du point de vue des patients. Méthodes. Ainsi, une étude transversale descriptive impliquant des patients ont été sélectionnés dans trois aires de santé et plus précisément dans des ménages, structures de santé conventionnelle et chez les praticiens de la médecine traditionnelle de Niono, Sirabala et N'Debougou. Des questionnaires structurés ont été utilisés pour collecter des informations. Le calcul du coût de traitement a été utilisé pour comparer le coût moyen de traitement du paludisme en médecine conventionnelle et traditionnelle. Résultats. Au total, 300 patients ont été sélectionnés. 52,7% des patients avaient recouru à la médecine conventionnelle, contre 32% pour l'automédication et 15,3% pour la médecine traditionnelle. Les patients avaient utilisé les ressources de ces trois systèmes de santé pour quatre principaux motifs. Le coût moyen du traitement par épisode de paludisme était estimé à 12,97 Euro en médecine conventionnelle contre 6,24 Euros en médecine traditionnelle. Le coût moyen du traitement de paludisme en automédication à base de médicaments conventionnels ou traditionnels était de 0,82 Euros. Conclusion. Dans notre étude, même si le coût du traitement du paludisme en médecine conventionnelle reste plus élevé que celui en médecine traditionnelle, contrairement aux idées reçues, les coûts des ressources de la médecine traditionnelle ne sont pas aussi bas qu'on le croit.

Introduction. In Mali, malaria management is done through conventional and traditional medicine, but little evaluation exists on the fi nancial implications of these approaches which coexist and are sometimes practiced concomitantly. The objective of this study was to evaluate the fi nancial costs of these two approaches from the patients' point of view. Methods. Thus, a descriptive cross-sectional study involving patients selected in three health areas and more precisely in households, conventional health structures and traditional medicine practitioners in Niono, Sirabala and N'Debougou. Structured questionnaires were used to collect information. The calculation of the cost of treatment was used to compare the average cost of treating malaria in conventional and traditional medicine. Results. Finally, 300 patients were selectionned and 52.7% of patients had used conventional medicine, compared to 32% for self-medication and 15.3% for traditional medicine. Patients had used the resources of these three health systems for four main reasons. The average cost of treatment per malaria episode was estimated at 12.97 Euros for conventional medicine versus 6.24 Euros for traditional medicine. The average cost of treatment of malaria by self-medication with conventional or traditional medicines was 0.82 Euros. Conclusion. In our study, even if the cost of treating malaria with conventional medicine remains higher than with traditional medicine, contrary to popular belief, the resource costs of traditional medicine are not as low as one might think

Determination of knowledge, attitude, and practice of Chinese and local people towards malaria prevention in Kano State, Nigeria

To date, malaria is still a major public health issue in the world. Africa remains the most affected continent with the highest malaria cases and deaths. Since more than one thousand Chinese citizens are living in Nigeria, examination of their knowledge, attitude, and practice compared with those of the local people may be essential towards malaria prevention. This study adopted cross-sectional research. A total of 137 Chinese people and 299 local people residing in Kano State, Nigeria constituted the study subjects. A questionnaire was used for the collection of data on socio-demography and predictors of attitudes. The Cronbach alpha statistic was used to analyze these data. Insecticide spraying, mosquito repellents, wearing protective clothing at night are the malaria preventive measures by both the local and Chinese people living in Kano state, Nigeria. However, there is a significant difference (p < 0.05) between the two groups, with a duration of stay in Nigeria, the use of mosquito, attitude, and practices playing impactful roles among the Chinese people. Hence, Chinese people demonstrated better knowledge and control of malaria transmission and prevention than the local people living in Kano state. In conclusion, attitudes and practices toward malaria diseases are the major causes of a high rate of malaria in Nigeria, particularly in Kano State.

Disability inclusion in malaria services in western Tanzania: A rapid barrier analysis

Background: Persons with disabilities generally face greater challenges in accessing healthcare and interventions compared with the general population. Malaria is one of the diseases that can seriously affect individuals with disabilities, as it requires early diagnosis and prompt treatment. Objective: This study explores the extent to which locally available malaria services and interventions are inclusive of persons with disabilities and identifies associated access barriers. Method: A qualitative case study focusing on social, cultural and health system factors associated with the inclusion of persons with disabilities in malaria services was conducted in Kigoma Region, western Tanzania. Thematic analysis of emerging themes identified barriers affecting access to locally available malaria services and interventions. Results: Inclusion of persons with disabilities in planning, implementation and reporting of health issues in different malaria programmes was reported to be limited. Persons with disabilities were unable to access malaria services because of different barriers such as the distance of the service provision sites, communication and information issues and a lack of financial resources. Conclusion: Persons with disabilities are widely excluded from malaria care provision across the entire health services paradigm, impacting access and utilisation to this vulnerable population. Barriers to malaria service access among persons with disabilities were physical, attitudinal, financial and informational. Contribution: The findings of this study identify that malaria intervention stakeholders need to take a holistic approach and fully involve individuals with disabilities at all levels and scope of malaria service planning and provision.

SD bioline malaria rapid diagnostic test performance and time to become negative after treatment of malaria infection in southwest Nigerian children

Context and Aim: Given the challenges of microscopy, we compared its performance with SD Bioline malaria rapid diagnostic test (MRDT) and polymerase chain reaction (PCR) and evaluated the time it took for positive results to become negative after treatment of children with acute uncomplicated malaria. Subjects and Methods: We present the report of 485 participants with complete MRDT, microscopy, and PCR data out of 511 febrile children aged 3­59 months who participated in a cohort study over a 12 month period in rural and urban areas of Ibadan, Nigeria. MRDT positive children received antimalaria and tested at every visit over 28 days. Speciation was also carried out by PCR. Results: With microscopy as the gold standard, SD-Bioline™ had 95.2% sensitivity, 66.4% specificity, 67.5% positive predictive value (PPV), and 94.9 negative predictive value (NPV), while with PCR the findings were 84.3% sensitivity, 66.5% specificity, 72.7% PPV, and 80.1% NPV. PCR speciation of malaria parasites revealed 91.6% Plasmodium falciparum, 18.9% Plasmodium malariae, and 4.4% Plasmodium ovale. Among the 47 children with P. malariae infections, 66.0% were coinfected with P. falciparum, while 54.6% cases of P. ovale occurred as coinfections with P. falciparum. The median time to a negative MRDT was 23.2 days, while the median time to a negative malaria microscopy was 3.8 days. The two survival curves were significantly different. Conclusions: The SD BiolineTM MRDT performed well, with remarkable persistence of rapid test-positive for an average of 23 days post treatment. The prevalence of P. malaria is somewhat greater than expected.

Achievements of the national malaria control and elimination program in the People's Republic of China: the Atlas of Malaria Transmission in China / 医学前沿

In 2017, China achieved the target of zero indigenous malaria case for the first time, and has been certified as malaria free by World Health Organization in 2021. To further summarize the historical achievements and technical experiences of the elimination program, a project on the Roadmap Analysis and Verification for Malaria Elimination in China was carried out. Results of the project were compiled and published as the Atlas of Malaria Transmission in China (The Atlas). The Atlas using modern digital information technologies, has been supported by various data from 24 malaria endemic provinces of China since 1950, to assess the changes in malaria epidemic patterns from 1950 to 2019 at national and provincial levels. The Atlas is designed as two volumes, including a total of 1850 thematic maps and more than 130 charts, consisting of introductory maps, thematic maps of malaria epidemic and control at national and provincial levels. It objectively and directly shows the epidemic history, evolution process, and great achievements of the national malaria control and elimination program in China. The Atlas has important reference value for summing up historical experience in the national malaria elimination program of China, and malaria control and elimination in other endemic countries in the world.

Indigenous ecological calendars and seasonal vector-borne diseases in the Colombian Amazon: an intercultural and interdisciplinary approach / Calendarios ecológicos indígenas y enfermedades estacionales transmitidas por vectores en la Amazonia colombiana: un enfoque intercultural e interdisciplinario

Traditional ecological knowledge of indigenous groups in the southeastern Colombian Amazon coincides in identifying the two main hydrological transition periods (wet-dry: August-November; dry-wet: March-April) as those with greater susceptibility to disease in humans. Here we analyze the association between indigenous knowledge about these two periods and the incidence of two vector-borne diseases: malaria and dengue. We researched seven "ecological calendars" from three regions in the Colombian Amazon, malaria and dengue cases reported from 2007 to 2019 by the Colombian National Institute of Health, and daily temperature and precipitation data from eight meteorological stations in the region from 1990-2019 (a climatological normal). Malaria and dengue follow a seasonal pattern: malaria has a peak from August to November, corresponding with the wet-dry transition (the "season of the worms" in the indigenous calendars), and dengue has a peak in March and April, coinciding with the dry-wet transition. Previous studies have shown a positive correlation between rainfall and dengue and a negative correlation between rainfall and malaria. However, as the indigenous ecological knowledge codified in the calendars suggests, disease prediction cannot be reduced to a linear correlation with a single environmental variable. Our data show that two major aspects of the indigenous calendars (the time of friaje as a critical marker of the year and the hydrological transition periods as periods of greater susceptibility to diseases) are supported by meteorological data and by the available information about the incidence of malaria and dengue.(AU)

Los conocimientos ecológicos tradicionales de grupos indígenas del sureste de la Amazonia colombiana coinciden en identificar dos principales periodos de transición hidrológica (seco-húmedo: agosto-noviembre; húmedo-seco: marzo-abril) como los de mayor susceptibilidad a enfermedades en humanos. Aquí analizamos la asociación entre el conocimiento indígena sobre estos dos periodos y la incidencia de dos enfermedades transmitidas por vectores: malaria y dengue. Investigamos siete calendarios ecológicos de tres regiones en la Amazonia colombiana, casos de dengue y malaria reportados de 2007 hasta 2019 por el Instituto Nacional de Salud de Colombia y datos diarios de temperatura y precipitación de ocho estaciones meteorológicas en la región, de 1990 a 2019 (una normal climatológica). Malaria y dengue siguen un patrón estacional, la malaria tiene un pico de agosto a noviembre, correspondiendo con la transición húmedo-seco (el "tiempo de gusano" según los calendarios indígenas), mientras que dengue tiene un pico de marzo a abril, coincidiendo con la transición seco-húmedo. Estudios previos mostraron una correlación positiva entre precipitación y dengue, y una correlación negativa entre precipitación y malaria. Sin embargo, como lo sugiere el conocimiento ecológico codificado en los calendarios indígenas, la predicción de enfermedades no puede reducirse a una correlación lineal con una sola variable medioambiental. Nuestros datos muestran que dos aspectos principales de los calendarios indígenas (el tiempo de friaje como un marcador crítico anual y los periodos de transición hidrológica como épocas de mayor susceptibilidad a enfermedades) están soportados por datos meteorológicos e información disponible acerca de la incidencia de malaria y dengue.(AU)

Prevalence and correlates of childhood anemia in the MINA-Brazil birth cohort study / Prevalência e preditores de anemia na infância no estudo de coorte de nascimentos MINA-Brasil

ABSTRACT OBJECTIVE: This study aimed to describe the prevalence and predictors of childhood anemia in an Amazonian population-based birth cohort study. METHODS: Prevalence of maternal anemia was estimated at delivery (hemoglobin [Hb] concentration < 110 g/L) in women participating in the MINA-Brazil birth cohort study and in their children, examined at ages one, two (Hb < 110 g/L), and five (Hb < 115 g/L). Moreover, ferritin, soluble transferrin receptor, and C-reactive protein concentrations were measured in mothers at delivery and in their 1- and 2-year-old children to estimate the prevalence of iron deficiency and its contribution to anemia, while adjusting for potential confounders by multiple Poisson regression analysis (adjusted relative risk [RRa]). RESULTS: The prevalence 95% confidence interval (CI) of maternal anemia, iron deficiency, and iron-deficiency anemia at delivery were 17.3% (14.0-21.0%), 42.6% (38.0-47.2%), and 8.7% (6.3-11.6)%, respectively (n = 462). At one year of age (n = 646), 42.2% (38.7-45.8%) of the study children were anemic, 38.4% (34.6-42.3%) were iron-deficient, and 26.3 (23.0-29.9) had iron-deficiency anemia. At two years of age (n = 761), these values decreased to 12.8% (10.6-15.2%), 18.1% (15.5-21.1%), and 4.1% (2.8-5.7%), respectively; at five years of age (n = 655), 5.2% (3.6-7.2%) were anemic. Iron deficiency (RRa = 2.19; 95%CI: 1.84-2.60) and consumption of ultra-processed foods (UPF) (RRa = 1.56; 95%CI: 1.14-2.13) were significant contributors to anemia at 1 year, after adjusting for maternal schooling. At 2 years, anemia was significantly associated with maternal anemia at delivery (RRa: 1.67; 95%CI: 1.17-2.39), malaria since birth (2.25; 1.30-3.87), and iron deficiency (2.15; 1.47-3.15), after adjusting for children's age and household wealth index. CONCLUSIONS: Anemia continues to be highly prevalent during pregnancy and early childhood in the Amazon. Public health policies should address iron deficiency, UPF intake, maternal anemia, and malaria to prevent and treat anemia in Amazonian children.

RESUMO OBJETIVO: O objetivo deste estudo foi descrever a prevalência e os preditores de anemia na infância em um estudo de coorte de nascimentos de base populacional amazônica. MÉTODOS: Estimou-se a prevalência de anemia materna no parto (concentração de hemoglobina [Hb] < 110 g/L) em mulheres participantes do estudo de coorte de nascimentos MINA-Brasil e em seus filhos, examinados nas idades um, dois (Hb < 110 g/L) e cinco anos (Hb < 115 g/L). Além disso, as concentrações de ferritina, receptor solúvel de transferrina e proteína C reativa foram medidas em mães no parto e em seus filhos de 1 e 2 anos de idade para estimar a prevalência de deficiência de ferro e sua contribuição para anemia, ajustando para potenciais fatores de confusão por análise de regressão múltipla de Poisson (risco relativo ajustado [RRa]). RESULTADOS: As prevalências com intervalo de confiança (IC) de 95% de anemia materna, deficiência de ferro e anemia ferropriva no parto foram de 17,3% (14,0-21,0%), 42,6% (38,0-47,2%) e 8,7% (6,3-11,6%), respectivamente (n = 462). No primeiro ano de idade (n = 646), 42,2% (38,7-45,8%) das crianças estudadas eram anêmicas, 38,4% (34,6-42,3%) eram deficientes em ferro e 26,3 (23,0-29,9%) tinham anemia ferropriva. Aos dois anos de idade (n = 761), esses valores diminuíram para 12,8% (10,6-15,2%), 18,1% (15,5-21,1%) e 4,1% (2,8-5,7%), respectivamente; aos cinco anos de idade (n = 655), 5,2% (3,6-7,2%) eram anêmicos. A deficiência de ferro (RRa = 2,19, IC95%: 1,84-2,60) e consumo de alimentos ultraprocessados (AUP) (RRa = 1,56, IC95%: 1,14-2,13) foram contribuintes significantes para anemia no 1° ano de idade, após ajuste para escolaridade materna. Aos 2 anos, a anemia associou-se significativamente à anemia materna no parto (RRa = 1,67; IC95%: 1,17-2,39), malária desde o nascimento (2,25; 1,30-3,87) e deficiência de ferro (2,15; 1,47-3,15), após ajuste para idade das crianças e índice de riqueza familiar. CONCLUSÕES: A anemia continua sendo altamente prevalente durante a gravidez e a primeira infância na Amazônia. Políticas públicas de saúde devem abordar a deficiência de ferro, o consumo de AUP, a anemia materna e a malária para prevenir e tratar a anemia em crianças amazônicas.

Identificação, caracterização e determinação de padrões da resposta imune de epítopos imunogênicos de Plasmodium vivax / Identification, characterization and determination of immune response patterns of immunogenic epitopes of Plasmodium vivax

O Plasmodium vivax representa um grande desafio no controle da malária devido a sua vasta distribuição ao redor do globo, grande frequência de infecções sub microscópicas e habilidade de induzir recaídas em consequência das formas evolutivas que podem ficar latentes no fígado por longos períodos (hipnozoítos). O recente aumento de cepas de P. vivax resistentes aos fármacos disponíveis, a evolução de formas mais virulentas do parasito e a produção precoce de gametócitos, característica desta espécie, contribuem para classificar a malária vivax como um problema de saúde pública que merece atenção. Ainda que reconhecido por suas características biológicas peculiares e pelo agravamento recente de sua virulência, poucos investimentos têm sido feitos no desenvolvimento de ferramentas de controle para vivax. Portanto, o presente estudo teve como objetivo identificar e caracterizar novos alvos potenciais utilizando amostras de diferentes áreas endêmicas ao redor do mundo (Brasil, Mali, Camboja e Estados Unidos da América). Para tanto, investigamos e caracterizamos uma proteína recém descoberta na urina de pacientes naturalmente infectados (PvVir14); e descrevemos o potencial imunogênico de epítopos de células B de uma das proteínas mais bem caracterizadas de P. vivax, a PvAMA-1. Anti-IgG circulantes contra PvVir14 apareceram em 61% e 34.5% dos indivíduos do Brasil e Camboja, respectivamente, enquanto que indivíduos de Mali (infectados com falciparum e não expostos a vivax), tiveram 0% de reconhecimento. Ainda, os níveis de anti-PvVir14 correlacionaram-se com aqueles contra outros antígenos de vivax já bem caracterizados, como a PvCSP e a PvDBP, que foram reconhecidos por 7.6% e 42% dos indivíduos respectivamente. Com relação ao perfil celular, indivíduos sororreativos para PvVir14 apresentaram níveis significativamente maiores de células B atípicas circulantes (CD 21- CD 27-), sugerindo que tal tipo celular possa estar ligado à resposta anti-PvVir14. Entre as células T, os níveis de CD4+ e CD8+ diferiram entre indivíduos com e sem anticorpos contra PvVir14 (menor e maior expressão, respectivamente), enquanto que os níveis de células NKT foram mais expressivos em indivíduos sem anti-PvVir14. Se tratando da PvAMA-1, a antigenicidade dos peptídeos com epítopos para células B previamente selecionados foi avaliada através de múltiplos ensaios sorológicos utilizando amostras de indivíduos com infecção aguda por P.vivax do norte do Brasil. Os peptídeos sintéticos foram reconhecidos por 45.5%, 48.7% e 31.2% (PI, PII e PII, respectivamente) dos indivíduos selecionados para o estudo. Quando sintetizados em conjunto (tripeptídeo), a reatividade aumentou para 62%, porcentagem comparável àquela obtida pela proteína em sua forma e tamanho originais (57%). Além disso, a reatividade anti-IgG conta o tripeptídeo foi reduzida em 42% pós-depleção, indicando que tais epítopos podem ser responsáveis por parte considerável da imunogenicidade da proteína. Esses resultados representam uma excelente perspectiva na identificação de novos alvos com potencial imunogênico para compor uma vacina, ou auxiliar no desenvolvimento de outras medidas de controle, como testes diagnósticos, já que contemplar diversos alvos do ciclo de vida do parasito parece ser a chave para alcançar a resposta robusta e protetora que uma vacina contra a malária vivax precisa para ter sucesso.

Plasmodium vivax is a major challenge for malaria control due to its wide geographic distribution, high frequency of submicroscopic infections, and ability to induce relapses due to the latent forms present in the liver (hypnozoites). The recent increase in drug-resistant P. vivax strains, the evolution toward more virulent forms and the early production of gametocytes adds up to make P. vivax malaria a public health issue of increasing importance. Besides its tricky biological features and new awareness of its virulence, minimal investments have been made in vaccine discovery for P. vivax. Given that, this study aimed to discover and characterize potential new targets for future vaccine development using samples from different endemic areas around the world (Brazil, Mali, Cambodia and United States of America). For this purpose, we investigated and characterized a novel protein recently discovered in the urine of naturally infected subjects (PvVir14) and described the immunogenic potential of peptides from a well-known vivax protein (PvAMA-1), which has been proved to have important B cell epitopes that can induce specific immune response. Circulating antibodies against PvVir14 appeared in 61% and 34.5% of subjects from Brazil and Cambodia, respectively, versus none (0%) of the P. falciparum-infected subjects from Mali who have no exposure to P. vivax. PvVir14 antibody levels correlated with those against other well-characterized sporozoite/liver (PvCSP) and blood stage (PvDBP-RII) antigens, which were recognized by 7.6% and 42% of Brazilians, respectively. Concerning the cellular immune profiling of Brazilian subjects, PvVir14 seroreactive individuals displayed significantly higher levels of circulating atypical (CD21− CD27−) B cells, raising the possibility that atypical B cells may be contribute to the PvVir14 antibody response. Among T cells, CD4+ and CD8+ levels differed (lower and higher, respectively) between subjects with versus without antibodies to PvVir14, while NKT cell levels were higher in those without antibodies. As for PvAMA-1, the antigenicity of the selected B-cell peptides was assessed by multiple serological assays using sera from acute P.vivax infected subjects. The synthetic peptides were recognized by 45.5%, 48.7% and 32.2% of infected subjects for peptides I, II and III respectively. Moreover, when synthetized together (tripeptide), the reactivity increases up to 62%, which is comparable to the reactivity found against the whole protein PvAMA-1 (57%). Furthermore, IgG reactivity against the tripeptide after depletion was reduced by 42%, indicating that these epitopes may be responsible for a considerable part of the protein immunogenicity. These results represent an excellent perspective on discovering new targets with immunogenic potential to compose a vaccine, or even to assist the development of other control measures, such as diagnostic tools, since contemplating several targets seems to be the key to achieving a robust and protective response that a malaria vaccine needs to be successful.