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1.
Braz. j. biol ; 83: e247422, 2023. tab, graf
Article in English | LILACS, VETINDEX | ID: biblio-1285631

ABSTRACT

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.


Subject(s)
Plasmodium falciparum/genetics , Antimalarials/pharmacology , Pakistan , Membrane Transport Proteins/genetics , Drug Resistance/genetics , Protozoan Proteins/genetics , Chloroquine/pharmacology , Multidrug Resistance-Associated Proteins/genetics , Alleles
2.
Rev. peru. med. exp. salud publica ; 39(3): 336-344, jul.-sep. 2022. tab, graf
Article in Spanish | LILACS-Express | LILACS | ID: biblio-1410004

ABSTRACT

RESUMEN Objetivos. Evaluar la variación de los perfiles hematológicos antes, durante y después del tratamiento de pacientes infectados con malaria no complicada por Plasmodium vivax (Pv) y P. falciparum (Pf) en una población de la región Loreto. Materiales y métodos. El estudio se realizó entre 2010 y 2012, en Zungarococha (Iquitos). Los 425 participantes tuvieron tres visitas (visita 1-día 0-antes del tratamiento, visita 2-día 7-durante tratamiento, visita 3-día 28-después del tratamiento), hemograma completo, diagnóstico microscópico y molecular (PCR). Resultados. En la primera visita, se encontraron 93 (21,9%) positivos a Pv y 34 (8,0%) a Pf. Todos los positivos mostraron una reducción en los indicadores hematológicos de hematocrito, recuento de glóbulos blancos (RGB), neutrófilos abastonados y segmentados, eosinófilos y plaquetas (p<0.001) en comparación con el grupo negativo. Se encontró un porcentaje mayor de neutrófilos abastonados en Pf y de neutrófilos segmentados en Pv comparado al grupo negativo. Se observó variaciones en los perfiles hematológicos después del tratamiento para ambas especies, los neutrófilos abastonados disminuyeron, las plaquetas aumentaron, los eosinófilos se incrementaron al día 7 y decaen el día 28, el hematocrito y los neutrófilos segmentados disminuyeron al día 7 y se normalizaron el día 28. Las diferencias entre especies en el tiempo mostraron una disminución diaria de neutrófilos abastonados en infectados con Pv que en Pf. Conclusiones. El perfil hematológico en pacientes positivos a malaria no complicada varía en el tiempo durante y después del tratamiento. Estos son indicadores de la progresión de la enfermedad y ayudan en la vigilancia terapéutica de pacientes infectados con Plasmodium.


ABSTRACT Objectives. To evaluate the variation of hematological profiles of patients infected with uncomplicated Plasmodium vivax (Pv) and P. falciparum (Pf) malaria before, during and after treatment in a population of the Loreto region. Materials and methods. This study was conducted between 2010 and 2012, in Zungarococha (Iquitos). The 425 participants had three visits (visit 1-day 0-before treatment, visit 2-day 7-during treatment, visit 3-day 28-after treatment), complete blood count, microscopic and molecular diagnosis (PCR). Results. At the first visit, 93 (21.9%) participants were found positive for Pv and 34 (8.0%) for Pf. All positives showed a reduction in hematocrit, white blood cell count (WBC), ablated and segmented neutrophils, eosinophils and platelets (p<0.001) compared to the negative group. A higher percentage of ablated neutrophils was found in Pf and segmented neutrophils in Pv compared to the negative group. Variations in hematological profiles were observed after treatment for both species; ablated neutrophils decreased, platelets increased, eosinophils increased at day 7 and declined at day 28, hematocrit and segmented neutrophils decreased at day 7 and normalized at day 28. Interspecies differences over time showed a bigger daily decrease in ablated neutrophils in Pv-infected when compared to Pf. Conclusions. The hematological profile in uncomplicated malaria-positive patients varies over time during and after treatment. These are indicators of disease progression and help in the therapeutic surveillance of Plasmodium-infected patients.

3.
Rev. peru. med. exp. salud publica ; 39(2): 241-244, abr.-jun. 2022. tab
Article in Spanish | LILACS-Express | LILACS | ID: biblio-1395061

ABSTRACT

RESUMEN Plasmodium vivax es la especie más común en la Amazonía peruana y ocasiona el 81% del total de casos de malaria. Presentamos el caso de un paciente adulto varón con malaria cerebral por Plasmodium vivax, que inicia con malestar general y fiebre, luego presenta convulsiones más de dos veces al día con pérdida de consciencia y limitación funcional motora. Se le realiza gota gruesa donde se observa trofozoítos de Plasmodium vivax y depresión de las tres series sanguíneas. Se inicia tratamiento con artesunato y clindamicina por cinco días, se le transfunde un paquete globular, y continua con primaquina por siete días. El paciente muestra mejoría clínica con secuela neurológica en extremidad inferior izquierda.


ABSTRACT Plasmodium vivax causes 81% of all malaria cases and is the most common species in the Peruvian Amazon. We present the case of a male patient with cerebral malaria caused by Plasmodium vivax, who had general malaise and fever, and then presented seizures more than twice a day with loss of consciousness and motor functional limitation. Plasmodium vivax trophozoites were detected by thick blood smear, besides, we also observed low counts of all three blood cell types. Treatment began with artesunate and clindamycin for five days, then one unit of packed red blood cells was transfused; treatment continued with primaquine for seven days. The patient showed clinical improvement with neurological sequelae in one lower limb.

4.
Biomédica (Bogotá) ; 42(2): 244-252, ene.-jun. 2022. tab
Article in Spanish | LILACS-Express | LILACS | ID: biblio-1403578

ABSTRACT

Resumen 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.


Abstract 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.

5.
Bol. venez. infectol ; 33(1): 24-29, ene-jun 2022.
Article in Spanish | LILACS-Express | LILACS | ID: biblio-1381960

ABSTRACT

La malaria representa un grave problema de salud pública en el país, por su morbilidad y mortalidad. Es importante conocer la patogenia y las manifestaciones clínicas de la malaria grave, en especial revisar el ciclo biológico del parásito, ya que la enfermedad comienza con la ruptura del esquizonte maduro, siendo las primeras manifestaciones clínicas: fiebre y anemia. La infección por Plasmodium falciparum es más severa y es mediada por el fenómeno de secuestro en la microvasculatura venosa profunda, mientras que Plasmodium vivax causa una enfermedad debilitante, rara vez mortal, pero en oportunidades se presentan manifestaciones graves que causan la muerte del paciente. Malaria grave se define por la presencia de signos clínicos y de laboratorio de disfunción de órganos vitales como sistema nervioso central, riñón, gastrointestinal, vías respiratorias y alteraciones hemodinámicas; la cual requiere el rápido reconocimiento de la enfermedad y del grado de severidad. Se debe hacer un manejo de índole general y prestar especial atención a la terapia antimalárica oportuna con Artesunato, primera línea en malaria grave, o Arthemeter o Quinina con Clindamicina según los protocolos nacionales e internacionales, para lograr una evolución satisfactoria. En consecuencia, es un reto enfrentar esta entidad y obliga a la constante actualización en las diferentes opciones cónsonas con las diferentes especies de Plasmodium patógeno.


Malaria represents a serious public health problem in the country, due to its morbidity and mortality. It is of most importance to know the pathogenesis and clinical manifestations of severe malaria, particularly to review the biological cycle of the parasite. The disease begins with the rupture of the mature schizont, with the first clinical manifestations being fever and anemia. Plasmodium falciparum infection is more severe and is mediated by the phenomenon of sequestration in the deep venous microvasculature, while Plasmodium vivax causes a debilitating disease, rarely fatal, but sometimes serious manifestations occur that cause the death of the patient. Severe malaria is defined by the presence of clinical and laboratory signs of dysfunction of vital organs such as the central nervous system, kidney, gastrointestinal, respiratory tract, and pathological hemodynamic changes that requires rapid disease recognition and degree of severity. General management and timely antimalarial therapy with Artesunate, first line in severe malaria, or Arthemeter, or Quinine with Clindamycin following national and international protocols, achieve a favorable outcome. Consequently, it is a challenge to face this entity and requires constant updating in the different options consistent with the different species of pathogenic Plasmodium.

6.
Rev. cuba. med. trop ; 74(1): e755, ene.-abr. 2022. tab, graf
Article in Spanish | LILACS-Express | LILACS | ID: biblio-1408893

ABSTRACT

RESUMEN Introducción: El reconocimiento temprano de los sujetos con malaria que pueden desarrollar complicaciones es fundamental para orientar el tratamiento. Se requiere un instrumento de predicción basado en características clínicas para predecir las complicaciones. Objetivo: Desarrollar y validar una herramienta de predicción clínica y paraclínica para predecir malaria complicada. Métodos: Se reclutaron de manera secuencial sujetos con diagnóstico de malaria complicada según criterios de la Organización Mundial de la Salud. Las características clínicas que se asociaron a malaria complicada fueron identificadas e incorporadas en un modelo de predicción logístico binario en una cohorte inicial de derivación y posteriormente validadas en una cohorte diferente de sujetos con la infección. Resultados: Se analizaron 584 sujetos en la cohorte de derivación y 898 en la cohorte de validación. La incidencia de malaria complicada fue de 21,2 % y 10,9 %, respectivamente. Las variables asociadas con malaria complicada fueron la disnea, fiebre por más de 72 horas, hemoglobina < 13 mg/dL, bilirrubina total > 6 mg/dL, nitrógeno ureico > 20 mg/dL, y Plasmodium vivax. El área bajo la curva de características operativas del receptor para el puntaje construido con estas variables en la cohorte de derivación fue de 0,70 y en la cohorte de validación fue de 0,69. Conclusión: Un puntaje pronóstico en pacientes con malaria que evalúe la presencia de disnea, fiebre persistente, nivel de hemoglobina, bilirrubina total, nitrógeno ureico e infección por P. vivax puede ser útil para clasificar de manera oportuna y objetiva a los sujetos que pueden desarrollar complicaciones.


ABSTRACT Introduction: Early identification of subjects with malaria who may develop complications is critical to guide treatment. A predictive tool based on the clinical characteristics of the disease is required to predict complications. Objective: To develop and validate a clinical and paraclinical tool to predict complicated malaria. Methods: Subjects with a diagnosis of complicated malaria according to the World Health Organization criteria were sequentially recruited. Clinical characteristics associated with complicated malaria were identified and incorporated into a binary logistic prediction model in an initial derivation cohort and, subsequently, validated in a different cohort of subjects with the infection. Results: 584 subjects were analyzed in the derivation cohort and 898 in the validation cohort. The incidence of complicated malaria was 21.2% and 10.9%, respectively. Variables associated with complicated malaria were dyspnea, fever for more than 72 hours, hemoglobin < 13 mg/dL, total bilirubin > 6 mg/dL, urea nitrogen > 20 mg/dL and Plasmodium vivax. The area under the receiver operating characteristics curve for the score constructed with these variables in the derivation cohort was 0.70 and in the validation cohort, it was 0.69. Conclusion: A prognostic score that evaluates the presence of dyspnea, persistent fever, hemoglobin level, total bilirubin, urea nitrogen and P. vivax infection in patients with malaria may be useful to classify in a timely and objective manner subjects who may develop complications.

7.
Biomédica (Bogotá) ; 42(1): 127-135, ene.-mar. 2022. tab, graf
Article in Spanish | LILACS | ID: biblio-1374512

ABSTRACT

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.


Subject(s)
Malaria , Plasmodium falciparum , Plasmodium vivax , Infectious Disease Transmission, Vertical , Ecuador
8.
Biomédica (Bogotá) ; 42(1): 147-158, ene.-mar. 2022. tab
Article in Spanish | LILACS | ID: biblio-1374514

ABSTRACT

Introducción. En Perú, la microscopía óptica con gota gruesa continúa utilizándose en el seguimiento de los pacientes con malaria o paludismo. Esta prueba es sencilla, pero requiere de equipamiento microscópico y personal idóneo que realice la lectura de las muestras. Los estudios sugieren que la prueba rápida OptiMAL-IT™ es una opción para dicho seguimiento. Objetivo. Evaluar la efectividad de OptiMAL-IT™ como test de seguimiento en pacientes con malaria en áreas endémicas del Perú. Materiales y métodos. Se hizo un estudio observacional, transversal y analítico de pruebas diagnósticas en pacientes con malaria. Se seleccionó a todos los pacientes que cumplían con los criterios de inclusión, procedentes de diferentes establecimientos de salud de los departamentos peruanos de San Martín y Loreto. El diagnóstico se hizo mediante microscopía óptica con gota gruesa y la prueba rápida de diagnóstico inmunocromatográfico OptiMAL-IT™ en los días 2, 3, 7 y 14 para Plasmodium vivax y hasta el día 21 de seguimiento para Plasmodium falciparum. Se calculó el porcentaje de los correctamente clasificados y los valores predictivos, y se compararon los resultados de la selva occidental y la selva oriental mediante ji al cuadrado o prueba exacta de Fisher. Resultados. Se registraron 262 pacientes de San Martín y 302 de Loreto. Los porcentajes correctamente clasificados y el valor predictivo negativo fueron superiores a 92,0 y 93,0 %, respectivamente, a partir del tercer día de seguimiento; no se encontraron diferencias estadísticas en los resultados obtenidos en la Amazonía occidental y los de la oriental. Conclusiones. La prueba OptiMAL-IT™ sería efectiva como test de seguimiento en los pacientes con diagnóstico de malaria en áreas endémicas del Perú.


Introduction: In Peru, optical microscopy with the thick smear test continues to be performed for the follow-up of malaria patients. This test is simple but it requires microscopic equipment and suitable staff to perform the reading of the samples. Studies suggest that the rapid OptiMAL-IT™ test is an option for follow-up. Objective: To evaluate the effectiveness of OptiMAL-IT™ as a follow-up test in malaria patients in endemic areas of Perú. Materials and methods: We conducted an observational, analytical cross-sectional study of diagnostic tests performed in patients with malaria. We selected all the patients attending different health facilities in the Peruvian departments of San Martín and Loreto who met the inclusion criteria. Optical microscopy with thick smear and OptiMAL-IT™ was used on days 2, 3, 7, and 14 for Plasmodium vivax and until day 21 of follow-up for Plasmodium falciparum. Percentages of correctly classified samples and predictive values were calculated, and the results were compared between the western jungle and the eastern jungle using Chi2 or Fisher's exact tests. Results: We registered 262 patients from San Martín and 302 from Loreto. The percentage of correctly classified cases and the negative predictive value were higher than 92.0% and 93,0%, respectively, from the third day of follow-up; no statistical differences were found in the results obtained from the western jungle and those from the eastern jungle. Conclusions: The OptiMAL-IT™ test would be effective as a follow-up test in patients diagnosed with malaria in endemic areas of Perú.


Subject(s)
Malaria/diagnosis , Peru , Plasmodium , Effectiveness , Aftercare
9.
Rev. Eugenio Espejo ; 16(1): 71-80, 20220111.
Article in Spanish | LILACS | ID: biblio-1353005

ABSTRACT

Objetivo. Determinar el estado actual de la prevalencia de Plasmodium en pacientes febriles que acuden al Hospital Básico Franklin Tello Nuevo Rocafuerte, cantón Aguarico, comparando con los datos de otros estudios epidemiológicos de la misma zona y la frontera con el vecino país de Perú. Métodos. Se realizó un estudio observacional descriptivo, retrospectivo de prevalencia. Desde 2011-2015 se recogieron 2.668 muestras de sangre capilar correspondientes al 55,04% de la población total del cantón Aguarico. Se empleó la técnica Gota Gruesa y Frotis coloreados con Giemsa para determinar positividad de Plasmodium. Resultados. El rango de variación de la prevalencia en los pobladores de las comunidades investigadas osciló entre 2,38% y 28,57%, detectándose mayor prevalencia en el sexo masculino (50,56 %). Estos hallazgos son similares a los estudios previos realizados entre 1992-1995, en la misma región del Aguarico. El Riesgo Relativo es (RR) es de 1,36 y el Odds Ratio (OR) fue de 1,71, siendo mayor el riesgo a desarrollar la enfermedad en los positivos. Conclusiones. Los datos de la investigación confirman la presencia de un foco autóctono de malaria producida por Plasmodium vivax en la selva amazónica ecuatoriana, excepto 2 casos de P. falciparum importados de Perú. Los casos diagnosticados clínicamente y mediante la técnica de la Gota Gruesa, fueron tratados con medicación antipalúdica con excelente adherencia al medicamento.


Objective. To determine the status of the prevalence of Plasmodium in febrile patients who attend the Franklin Tello Nuevo Rocafuerte Basic Hospital, Aguarico town, comparing the results obtained with data from other epidemiological studies in the same area, and places near the border with Peru. Methods. A descriptive, retrospective, observational study of prevalence was carried out. From 2011-2015 2,668 capillary blood samples were collected corresponding to 55.04% of the total population of the Aguarico town. The Thick Drop and Giemsa-stained smear technique was used to determine Plasmodium positivity. Results. The range of variation of the prevalence in the inhabitants of the investigated communities ranged between 2.38% and 28.57%, detecting a higher prevalence in males (50.56%). These findings are like previous studies carried out between 1992-1995, in the same Aguarico region. The Relative Risk (RR) is 1.36 and the Odds Ratio (OR) was 1.71, with the risk of developing the disease being greater in the positives. Conclusions. The research data confirm the presence of an autochthonous focus of malaria produced by Plasmodium vivax in the Ecuadorian Amazon rainforest, except for 2 cases of P. falciparum imported from Peru. The cases diagnosed clinically and using the thick gout technique were treated with antimalarial medication with excellent adherence to the medication.


Subject(s)
Humans , Male , Female , Prevalence , Amazonian Ecosystem , Malaria , Plasmodium vivax , Indigenous Peoples , Antimalarials
10.
Tropical Biomedicine ; : 209-214, 2022.
Article in English | WPRIM | ID: wpr-936920

ABSTRACT

@#Circumsporozoite protein (CSP) is a sporozoite major surface protein of Plasmodium species. The protein showed promising protection level as a vaccine candidate against Plasmodium falciparum infection. There is a lack of studies on P. knowlesi CSP (PkCSP) as a vaccine candidate due to the high polymorphic characteristic of central repeat region. Recent studies showed the protein has a relatively conserved region at the C-terminal, which consists of T- and B-cell epitopes. This could be the target region for vaccine development against the pre-erythrocytic stage of the parasite. In this study, recombinant PkCSP was expressed using Escherichia coli system. Recombinant PkCSP was immunized in animal models and the antiserum was evaluated using immunoblot analysis. Results showed that PkCSP can be successfully expressed using the bacterial system. Endpoint titre of the antiserum were ranged up to 1:819200. Immunoblot analysis showed the antiserum recognized recombinant PkCSP but not total protein extract from P. knowlesi erythrocytic stage. In conclusion, PkCSP could elicit strong immune response in animal models. However, serum antibodies could not recognize protein from the parasite’s erythrocytic stage extract indicating it is not expressed at the erythrocytic stage. Therefore, PkCSP remains as a potential pre-erythrocytic vaccine candidate against P. knowlesi infection.

11.
Tropical Biomedicine ; : 66-72, 2022.
Article in English | WPRIM | ID: wpr-936400

ABSTRACT

@#Recent reports of natural human infection by Plasmodium cynomolgi indicate the increased risk of zoonotic transmission by this simian parasite. The P. cynomolgi Duffy binding protein 2 (PcDBP2) has a potential role in the invasion pathway of host erythrocytes, and it is a possible vaccine candidate against cynomolgi malaria. This study investigates the genetic diversity, haplotypes, and natural selection of PcDBP2 region II from isolates collected from wild macaques in Peninsular Malaysia. Blood samples from 50 P. cynomolgi-infected wild macaques were used in the study. Genomic DNA extracted from the blood samples was used as template for PCR amplification of the PcDBP2 region II. The amplicons were cloned into a plasmid vector and sequenced. MEGA X and DnaSP ver.6.12.03 programmes were used to analyse the DNA sequences. A genealogical relationship of PcDBP2 region II were determined using haplotype network tree on NETWORK ver.10.2. Result showed high genetic diversity (ð = 0.017 ± 0.002; Hd = 1.000 ± 0.001) of the PcDBP2 region II. The Z-test indicates a purifying selection, with population expansion as shown in Tajima’s D analysis. A total of 146 haplotypes of PcDBP2 region II were observed. Phylogenetic tree analysis showed that these haplotypes were grouped into three allelic types (136 for Strain B type, 9 for Berok type, and 1 recombinant type). In the haplotype network, PcDBP2 region II revealed no geographical groupings but was divided into two distinct clusters.

12.
Article in Chinese | WPRIM | ID: wpr-920750

ABSTRACT

Objective To investigate the effects of nitroquine on the development of different stages of Plasmodium yoelii in Anopheles stephensi. Methods An. stephensi mosquitoes were fed with conventional sucrose water or sucrose water containing 100 μmol/L nitroquine one day prior to P. yoelii infection. Following starvation for 24 hours, mosquitoes were fed with the blood of Kunming mice infected with P. yoelii, and the number of oocysts was observed in the stomach of An. stephensi. After 6 days and 14 days of infection, the mosquitoes were starved for 24 hours, and then fed with conventional sucrose water or nitroquine treated sucrose water. The An. stephensi mosquitoes were starved for 24 hours 6 and 14 days post-infection with P. yoelii, and then fed with conventional sucrose water or nitroquine-containing sucrose water, the numbers of P. yoelii sporozoites were examined in the hemolymph and salivary glands of An. stephensi. Results Following exposure to nitroquine-containing sucrose water one day prior to P. yoelii infections, the number of P. yoelii oocysts was significantly lower in the An. stephensi stomach on day 7 (119.2 ± 16.1 vs. 207.3 ± 21.8; t = 3.207, P < 0.05). After conventional sucrose water was ceased for 24 hours on day 6, and An. stephensi was fed with nitroquine-containing sucrose water, the number of P. yoelii sporozoites peaked in the hemolymph on day 14 in the nitroquine treatment group (952.3 ± 22.7) and on day 12 in the sucrose water treatment group (1 287.0 ± 39.0), and there was a significant difference in the number of sporozoites in the salivary glands between the nitroquine treatment group and the sucrose water treatment group (9 467.0 ± 1 304.0 vs. 10 533.0 ± 758.7; t = 0.707, P = 0.506) on day 17. After conventional sucrose water was ceased for 24 hours on day 14, and An. stephensi was fed with nitroquine-containing sucrose water, the number of sporozoites in the salivary glands was significantly greater in the nitroquine treatment group than in the sucrose water treatment group (21 900.0 ± 2 613.0 vs. 10 533.0 ± 732.3; t = 4.188, P < 0.05). Conclusions Nitroquine treatment exhibits diverse effects the development of different stages of P. yoelii, and nitroquine treatment may reduce the transmission of P. yoelii in uninfected An. stephensi.

13.
Article in Chinese | WPRIM | ID: wpr-920741

ABSTRACT

Objective To analyze the polymorphism of Plasmodium lactate dehydrogenase (pLDH) gene and predict B-cell epitopes in pLDH peptides in four species of human malaria parasites. Methods The blood samples and epidemiological characteristics were collected from malaria cases in Yunnan Province registered in the National Notifiable Disease Report System. The pLDH genes of four human Plasmodium species were amplified using nested PCR assay and sequenced. The polymorphisms of pLDH genes was analyzed using the software MEGA version 7.0.26 and DnaSP version 5.10, and the B-cell epitopes were predicted in pLDH peptides using the Immune Epitope Database (IEDB). Results The sequences of P. vivax LDH (PvLDH), P. falciparum LDH (PfLDH), P. ovale LDH (PoLDH) and P. malariae LDH (PmLDH) genes were obtained from 153, 29, 17 and 11 blood samples from patients with P. vivax, P. falciparum, P. ovale and P. malariae malaria, respectively, which included 15, 2, 4 and 2 haplotypes and had a nucleotide diversity (π) of 0.104. A high level of intra-species differentiation was seen in the PoLDH gene (π = 0.012), and the π values were all < 0.001 for PvLDH, PfLDH and PmLDH genes. Active regions of B-cell antigen were predicted in the pLDH peptide chain of four human malaria parasites, of 4 to 5 in each chain, and the activity score was approximately 0.430. Among these peptide chains, the “86-PGKSDKEWNRD-96” short-peptide was a B-cell epitope shared by all four species of human malaria parasites, and the “266-GQYGHS (T)-271” short-peptide was present in PvLDH and PoLDH peptide chains, while “212-EEVEGIFDR-220” was only found in the PvLDH peptide chain, and “208-LISDAE-213” was only seen in the PfLDH peptide chain. Conclusions The PoLDH gene polymorphism may be derived from the weak negative purification selection, while PvLDH, PfLDH and PmLDH genes may maintain a relatively conservative state. There may be two B-cell epitopes “212-EEVEGIFDR-220” and “208-LISDAE-213” in the proximal region of the C terminal in the pLDH peptide chain, which is feasible to differentiate between P. vivax and P. falciparum infections.

14.
Frontiers of Medicine ; (4): 83-92, 2022.
Article in English | WPRIM | ID: wpr-929204

ABSTRACT

The dihydrofolate reductase (dhfr) and dihydropteroate synthetase (dhps) genes of Plasmodium vivax, as antifolate resistance-associated genes were used for drug resistance surveillance. A total of 375 P. vivax isolates collected from different geographical locations in China in 2009-2019 were used to sequence Pvdhfr and Pvdhps. The majority of the isolates harbored a mutant type allele for Pvdhfr (94.5%) and Pvdhps (68.2%). The most predominant point mutations were S117T/N (77.7%) in Pvdhfr and A383G (66.8%) in Pvdhps. Amino acid changes were identified at nine residues in Pvdhfr. A quadruple-mutant haplotype at 57, 58, 61, and 117 was the most frequent (57.4%) among 16 distinct Pvdhfr haplotypes. Mutations in Pvdhps were detected at six codons, and the double-mutant A383G/A553G was the most prevalent (39.3%). Pvdhfr exhibited a higher mutation prevalence and greater diversity than Pvdhps in China. Most isolates from Yunnan carried multiple mutant haplotypes, while the majority of samples from temperate regions and Hainan Island harbored the wild type or single mutant type. This study indicated that the antifolate resistance levels of P. vivax parasites were different across China and molecular markers could be used to rapidly monitor drug resistance. Results provided evidence for updating national drug policy and treatment guidelines.


Subject(s)
Antimalarials/pharmacology , China/epidemiology , Drug Combinations , Drug Resistance/genetics , Folic Acid Antagonists/pharmacology , Humans , Mutation , Plasmodium vivax/genetics , Prevalence
15.
Article in Chinese | WPRIM | ID: wpr-940623

ABSTRACT

ObjectiveThe tolerance of C57BL/6 mice to artemisinin-sensitive and -resistant strains of Plasmodium berghei (Pb) K173 and the differences in blood parameters, spleen coefficient and spleen structure during infection were compared to explore whether the artemisinin resistance of Pb would aggravate malaria infection. MethodPbK173 artemisinin-sensitive and -resistant strains were tested in parallel. C57BL/6 mice were randomly divided into 1 control group, 4 artemisinin-sensitive strain groups and 4 artemisinin-resistant strain groups by body weight. Each infection group was simultaneously inoculated (ip) with 1×107 infected red blood cells (iRBCs) of sensitive/resistant strain. For the mice in the survival test group, the body weight was recorded every day post infection, and the tail vein blood smear was collected to calculate the Pb infection rate. In the other infection groups, peripheral blood and spleen were collected on 2, 5 and 9 d after infection. Peripheral blood parameters, spleen coefficient, pathological section of spleen and spleen cells were detected in each group. ResultOn 1-3 d after infection, the infection rate of the resistant strain (0.4±0.0, 0.8±0.1, 1.9±0.4)% was always higher than that of the sensitive strain (0.2±0.1, 0.4±0.1, 1.1±0.3)% (P<0.01). From the 4th d of infection, the infection rate of the two groups gradually approached. The survival period of the sensitive strain group (20.5±1.2) d was shorter than that of the resistant strain group (23.3±1.4) d (P<0.01). On the 9th d, the white blood cell count of the sensitive strain group (16.2±1.1)×109 cells/L was higher than that of the resistant strain group (10.6±1.8)×109 cells/L (P<0.01). Flow cytometry analysis of spleen cells showed that the sensitive strain group (3.6±0.4) demonstrated a higher CD4+/CD8+ value than the resistant strain group (2.3±0.2) on the 9th d (P<0.01). The spleen of C57BL/6 infected mice was gradually enlarged during infection, and on the 9th d, the resistant strain group (3.1±0.1)% showed a higher spleen coefficient than the sensitive strain group (2.7±0.2)% (P<0.01). In the early stage of C57BL/6 infected mice, the red pulp of spleen was hyperemic and swollen. On the 9th d, the marginal area of the spleen disappeared and the structure of the red and white pulp was destroyed. ConclusionWithout drug treatment, the protective immune responses of peripheral blood and spleen of C57BL/6 mice were more sensitive to PbK173 artemisinin-sensitive strain. The artemisinin-resistant strain of PbK173 bred with mouse-to-mouse blood transmission and increased artemisinin dose exhibited shortened growth period and reduced toxicity.

16.
Mem. Inst. Oswaldo Cruz ; 117: e210330, 2022. tab, graf
Article in English | LILACS-Express | LILACS | ID: biblio-1386343

ABSTRACT

BACKGROUND Understanding the epidemiology of malaria through the molecular force of the blood-stage infection of Plasmodium vivax (molFOB) may provide a detailed assessment of malaria transmission. OBJECTIVES In this study, we investigated risk factors and spatial-temporal patterns of incidence of Plasmodium infection and clinical malaria episodes in three peri-urban communities of Manaus, Western Brazilian Amazon. METHODS Monthly samples were collected in a cohort of 1,274 individuals between April 2013 and March 2014. DNA samples were subject to Plasmodium species. molFOB was calculated by counting the number of genotypes observed on each visit, which had not been present in the preceding two visits and adjusting these counts by the respective times-at-risk. FINDINGS Respectively, 77.8% and 97.2% of the population remained free of P. vivax and P. falciparum infection. Expected heterozygosity for P. vivax was 0.69 for MSP1_F3 and 0.86 for MS2. Multiplicity of infection in P. vivax was close to the value of 1. The season was associated with P. vivax positivity [adjusted hazard ratio (aHR) 2.6 (1.9-5.7)] and clinical disease [aHR 10.6 (2.4-47.2)]. P. falciparum infection was associated with previous malarial episodes [HR 9.7 (4.5-20.9)]. Subjects who reported possession of a bed net [incidence rate ratio (IRR) 1.6 (1.2-2.2)] or previous malaria episodes [IRR 3.0 (2.0-4.5)] were found to have significantly higher P. vivax molFOB. MAIN CONCLUSIONS Overall, P. vivax infection prevailed in the area and infections were mostly observed as monoclonal. Previous malaria episodes were associated with significantly higher P. vivax molFOB.

17.
Mem. Inst. Oswaldo Cruz ; 117: e210331, 2022. tab, graf
Article in English | LILACS-Express | LILACS | ID: biblio-1386364

ABSTRACT

BACKGROUND One of the most controversial factors about malaria parasite culture is the gaseous composition used. The most commonly used one consists of a mixture poor in O2 and rich in CO2. OBJECTIVES The present study aimed to share standard methods from our research group simplifying Plasmodium falciparum cultures by employing atmospheric air (ATM) and reusable glass bottles under agitation. METHODS Here, it was compared the parasite viability, free oxygen in media, and drug sensitivity between different strains and isolates maintained for long periods under ATM or classic conditions. FINDINGS The oxygen concentration in media under ATM was slightly superior to that observed in human blood and the media under the classic gaseous mixture. However, ATM or the use of glass bottles did not affect parasitic proliferation after several years of culture. Noticeably, the introduction of ATM altered reversibly the efficacy of several antimalarials. This influence was different between the strains and isolate. CONCLUSIONS ATM conditions and shaken flasks could be used as a standard method condition for culture manutention since they do not differ greatly from classical 5% O2 gas mixtures in terms of parasite proliferation and do not impose non-reversible changes to P. falciparum physiology.

18.
Article in English | LILACS-Express | LILACS | ID: biblio-1360794

ABSTRACT

ABSTRACT Malaria is the most important vector-borne disease in the world and a challenge for control programs. In Brazil, 99% of cases occur in the Amazon region. In the extra-Amazonian region, a non-endemic area, epidemiological surveillance focuses on imported malaria and on autochthonous outbreaks, including cases with mild symptoms and low parasitemia acquired in the Atlantic Forest biome. In this scenario, cases are likely to be underreported, since submicroscopic parasitemias are not detected by thick blood smear, considered the reference test. Molecular tests are more sensitive, detecting asymptomatic individuals and mixed infections. The aim of this study was to propose a more efficient alternative to detect asymptomatic individuals living in areas of low malaria endemicity, as they are reservoirs of Plasmodium that maintain transmission locally. In total, 955 blood samples from residents of 16 municipalities with autochthonous malaria outbreaks in the Sao Paulo State were analyzed; 371 samples were collected in EDTA tubes and 584 in filter paper. All samples were initially screened by a genus-specific qPCR targeting ssrRNA genes (limit of detection of 1 parasite/µL). Then, positive samples were subjected to a nested PCR targeting ssrRNA and dihydrofolate reductase-thymidylate synthase genes (limit of detection of 10 parasites/µL) to determine Plasmodium species. The results showed a statistically significant difference (K = 0.049; p < 0.0001) between microscopy positivity (6.9%) and qPCR (22.9%) for EDTA-blood samples. Conversely, for samples collected in filter paper, no statistical difference was observed, with 2.6% positivity by thick blood smear and 3.1% for qPCR (K = 0.036; p = 0.7). Samples positive by qPCR were assayed by a species-specific nested PCR that was in turn positive in 26% of samples (16 P. vivax and 4 P. malariae ). The results showed that molecular protocols applied to blood samples from residents in areas with autochthonous transmission of malaria were useful to detect asymptomatic patients who act as a source of transmission. The results showed that the genus-specific qPCR was useful for screening positives, with the subsequent identification of species by nested PCR. Additional improvements, such as standardization of blood plotting on filter paper and a more sensitive protocol for species determination, are essential. The qPCR-based algorithm for screening positives followed by nested PCR will contribute to more efficient control of malaria transmission, offering faster and more sensitive tools to detect asymptomatic Plasmodium reservoirs.

19.
Mem. Inst. Oswaldo Cruz ; 117: e220085, 2022. graf
Article in English | LILACS-Express | LILACS | ID: biblio-1394476

ABSTRACT

BACKGROUND Malaria is a disease that affects many tropical and subtropical countries, including Brazil. The use of tests for malaria detection is one of the fundamental strategies recommended by the World Health Organization for the control and eradication of the disease. The lack of diagnostic tests leads to an increase in transmission and non-reporting cases. OBJECTIVES This work described an electrochemical immunosensor for detecting Plasmodium vivax lactate dehydrogenase antigen (Ag-PvLDH). METHODS The device has developed by immobilising egg yolk IgY antibodies (Ab-PvLDH) on a gold electrode surface using cysteamine as linker. The immunosensor fabrication was followed by differential pulse voltammetry, and contact angle measurements were performed to characterise the modified gold electrode surface. FINDINGS The results for Ag-PvLDH determination exhibit a linear response at 10-50 µg mL-1 concentration range, with a limit of detection of 455 ng mL-1. The excellent selectivity of the device was confirmed. MAIN CONCLUSIONS The developed immunosensor showed a good performance, therefore, it can be considered an alternative test to detect malaria caused by P. vivax.

20.
Article in English | LILACS-Express | LILACS | ID: biblio-1365417

ABSTRACT

ABSTRACT Despite the many efforts of researchers around the world, there is currently no effective vaccine for malaria. Numerous studies have been developed to find vaccine antigens that are immunogenic and safe. Among antigen candidates, Plasmodium falciparum merozoite surface protein 3 (MSP3) has stood out in a number of these studies for its ability to induce a consistent and protective immune response, also being safe for use in humans. This review presents the main studies that explored MSP3 as a vaccine candidate over the last few decades. MSP3 formulations were tested in animals and humans and the most advanced candidate formulations are MSP3-LSP, a combination of MSP3 and LSP1, and GMZ2 (a vaccine based on the recombinant protein fusion GLURP and MSP3) which is currently being tested in phase II clinical studies. This brief review highlights the history and the main formulations of MSP3-based vaccines approaches against P. falciparum .

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