Malaria in pregnant women living in areas of low transmission on the southeast Brazilian Coast: molecular diagnosis and humoural immunity profile

Studies on autochthonous malaria in low-transmission areas in Brazil have acquired epidemiological relevance because they suggest continued transmission in what remains of the Atlantic Forest. In the southeastern portion of the state of São Paulo, outbreaks in the municipality of Juquitiba have been the focus of studies on the prevalence of Plasmodium, including asymptomatic cases. Data on the occurrence of the disease or the presence of antiplasmodial antibodies in pregnant women from this region have not previously been described. Although Plasmodium falciparum in pregnant women has been widely addressed in the literature, the interaction of Plasmodium vivax and Plasmodium malariae with this cohort has been poorly explored to date. We monitored the circulation of Plasmodium in pregnant women in health facilities located in Juquitiba using thick blood film and molecular protocols, as well as immunological assays, to evaluate humoural immune parameters. Through real-time and nested polymerase chain reaction, P. vivax and P. malariae were detected for the first time in pregnant women, with a positivity of 5.6%. Immunoassays revealed the presence of IgG antibodies: 44% for ELISA-Pv, 38.4% for SD-Bioline-Pv and 18.4% for indirect immunofluorescence assay-Pm. The high prevalence of antibodies showed significant exposure of this population to Plasmodium. In regions with similar profiles, testing for a malaria diagnosis might be indicated in prenatal care.

Malaria diagnosis from pooled blood samples: comparative analysis of real-time PCR, nested PCR and immunoassay as a platform for the molecular and serological diagnosis of malaria on a large-scale

Malaria diagnoses has traditionally been made using thick blood smears, but more sensitive and faster techniques are required to process large numbers of samples in clinical and epidemiological studies and in blood donor screening. Here, we evaluated molecular and serological tools to build a screening platform for pooled samples aimed at reducing both the time and the cost of these diagnoses. Positive and negative samples were analysed in individual and pooled experiments using real-time polymerase chain reaction (PCR), nested PCR and an immunochromatographic test. For the individual tests, 46/49 samples were positive by real-time PCR, 46/49 were positive by nested PCR and 32/46 were positive by immunochromatographic test. For the assays performed using pooled samples, 13/15 samples were positive by real-time PCR and nested PCR and 11/15 were positive by immunochromatographic test. These molecular methods demonstrated sensitivity and specificity for both the individual and pooled samples. Due to the advantages of the real-time PCR, such as the fast processing and the closed system, this method should be indicated as the first choice for use in large-scale diagnosis and the nested PCR should be used for species differentiation. However, additional field isolates should be tested to confirm the results achieved using cultured parasites and the serological test should only be adopted as a complementary method for malaria diagnosis.

Transfusion-transmitted malaria: case report of asymptomatic donor harboring Plasmodium malariae / Malária transfusional: relato de caso de doador assintomático infectado por Plasmodium malariae

Malaria in Brazil is endemic in the Amazon region, but autochthonous cases with low parasitaemia occur in the Atlantic Forest area of the country. According to Brazilian legislation no test is mandatory for blood donors from non-endemic areas. However if they have traveled to malaria transmission regions they are deferred for six months before they can donate. This report describes a transfusion-transmitted malaria case in Sao Paulo, Brazil, where one recipient received infected blood and developed the disease. He lived in Sao Paulo and had no previous transfusion or trips to endemic areas, including those of low endemicity, such as Atlantic Forest. Thick blood smears confirmed Plasmodiummalariae. All donors lived in Sao Paulo and one of them (Donor 045-0) showed positive hemoscopy and PCR. This asymptomatic donor had traveled to Juquia, in the Atlantic Forest area of S ao Paulo State, where sporadic cases of autochthonous malaria are described. DNA assay revealed P. malariae in the donor's (Donor 045-0) blood. Serum archives of the recipient and of all blood donors were analyzed by ELISA using both P. vivax and P. falciparum antigens, and IFAT with P. malariae. Donor 045-0's serum was P. malariae IFAT positive and the P. vivax ELISA was reactive. In addition, two out of 44 donors' archive sera were also P. vivax ELISA reactive. All sera were P. falciparum ELISA negative. This case suggests the need of reviewing donor selection criteria and deferral strategies to prevent possible cases of transfusion-transmitted malaria.

No Brasil a malária é endêmica na Amazônia, porém casos autóctones com baixas parasitemias ocorrem na área costeira de Mata Atlântica. De acordo com a legislação brasileira, não são obrigatórios testes para detecção de malária em doadores de sangue de áreas não-endêmicas; entretanto são excluídos por seis meses aqueles com relato de deslocamento para áreas de transmissão. Este trabalho descreve um caso de malária transfusional ocorrido em São Paulo, Brasil, em que um paciente recebeu sangue infectado, desenvolvendo a doença. Ele residia em São Paulo e não apresentava histórico de transfusão anterior ou deslocamentos para áreas endêmicas, incluindo as de baixa endemicidade, como a Mata Atlântica. A gota espessa revelou Plasmodium malariae. Os doadores eram residentes em São Paulo e um deles (045-0) apresentou hemoscopia e PCR positivos. Este era assintomático com PCR positiva para P. malariae e viagem para Juquiá, Mata Atlântica de São Paulo, onde são descritos casos esporádicos de malária autóctone. Amostras de soro do receptor e de todos os doadores foram ensaiadas por ELISA com antígenos de P. vivax e P. falciparum e RIFI com P. malariae. O doador 045-0 apresentou RIFI positiva para P. malariae. ELISA-P. vivax foi reagente no doador infectado (045-0) e em dois dos 44 doadores. Todos os soros foram negativos com antígeno de P. falciparum. Este caso aponta a necessidade de revisão dos critérios de triagem clínico-epidemiológica para evitar casos transfusionais e também adequar as estratégias de exclusão de doadores de sangue.

Prevalence and level of antibodies to the circumsporozoite protein of human malaria parasites in five states of the Amazon region of Brazil

The aim of this study was to determine the prevalence of malaria infection and antibodies against the repetitive epitopes of the circumsporozoite (CS) proteins of Plasmodium falciparum, P. malariae, P. vivax VK210, P. vivax VK247, and P. vivax-like in individuals living in the states of Rondônia, Pará, Mato Grosso, Amazonas, and Acre. Active malaria transmission was occurring in all studied sites, except in Acre. P. falciparum was the predominant species in Pará and Rondônia and P. vivax in Mato Grosso. Infection by P. malariae was low but this Plasmodium species was detected in Rondônia (3.5 percent), Mato Grosso (2.5 percent), and Pará (0.8 percent). High prevalence and levels of serological reactivity against the CS repeat peptides of P. falciparum were detected in Rondônia (93 percent) and Pará (85 percent). Sera containing antibodies against the CS repeat of P. malariae occurred more frequently in Rondônia (79 percent), Pará (76 percent), and Amazonas (68 percent). Antibodies against the repeat epitope of the standard CS protein of P. vivax VK210, P. vivax VK247, and P. vivax-like were more frequent in Rondônia, Pará, and Mato Grosso. The high frequency of reactions to P. malariae in most of the areas suggests that the infection by this Plasmodium species has been underestimated in Brazil.

The new and the old in malaria immunopathology

O termo "imunopatologia" pode ser considerado tanto como "uma patologia do sistema imune" quanto como "uma patologia provocada pelo sistema imune". Isso se aplica também no caso de infecções parasitárias como a malária na qual ambos os tipos de fenômeno säo comumente observados. Por quase meio século após a descoberta do Plasmodium, clínicos e patologistas deixaram-se seduzir pela fácil tentaçäo de explicar fenômenos como a anemia e a malária cerebral como complicações mecânicas da doença, resultantes da açäo direta de formas maduras do parasita, destruindo hemácias ou obliterando vasos capilares profundos. Nas últimas décas, entretanto, progressos substanciais no conhecimento da estrutura e funções das citocinas levaram a uma profunda revoluçäo na maneira de se ver a patologia da malária. Os conceiros atuais tendem a considerar que a maior parte da patogenia da malária resulta da interaçäo de distintos processos, e a dar mais ênfase ao efeito modulador de toxinas parasitárias na cascata de ativaçäo de citocinas do que aos óbvios componentes mecânicos da infecçäo parasitária. Neste artigo, revisamos criticamente alguns aspectos da patologia da malária que poderiam resultar de um sistema imune alterado. A anemia e a forma cerebral da malária Plasmodium falciparum assim como o envolvimento renal que acompanha a infecção por P. malariae. Também discutimos os mecanismos envolvidos nas perturbações do sistema imune. Ativação policlonal linfocitária, autoimunidade e imunodepressão.

Antibodies anti Bloodstream and Circumsporozoite antigens (Plasmodium

During 1992-1994, 33 malaria cases were reported in two regions in Brazil were few sporadic atypical cases occur, most of them in home owners, who are weekenders, while home caretakers live there permanently. Indirect Flurescent antibody Test (IFLAT), with Plasmodium vivax, and Enzime Linked Immunosorbent Assay (ELISA) with repeat peptides of the circumsporozoite (CS) proteins of the 3 known P. vivax variants and P. malarie/P. brasilianum, were performed on 277 sera, obtained within a 5 to 10 km range of malaria cases. Very rarely did any of these donors recall typical malaria episodes. Blood smears of all but 5 were negative. One of the 5 malaria cases included in our serology was of a home owner, 1 of a permanent resident, 3 from Superintendencia de Controle de Endemias employees who went there to capture mosquitoes. In region 1the prevalence of IFLAT positive sera was 73 per cent and 28 per cent among caretakers, 18 per cent and 9.6 per cent among home owners. In region 2 (3 localities) no distinction was possible between caretakers and home owners, IFAT positivity being 38 per cent, 28 per cent and 7 per cent. The relative percentage of positive anti-CS repeats ELISA, differed for each of the peptides among localities. Dwellings are in the vicinity of woods, where monkeys are frequently seen. The origin of these malaria cases, geographical differences and high seropositivity is discussed.

Estudios epidemiológicos en los SILAIS en Nicaragua / Epidemiological studies on the SILAIS

Contiene 6 investigaciones realizadas por epidemiólogos de los SILAIS de Nicaragua: 1) TRATAMIENTO HOSPITALARIO DE LA MALARIA EN LAS EMBARAZADAS Y PUERPERAS MANAGUA,NICARAGUA. 2) PERFIL CLINICO DE LA MALARIA EN NICARAGUA: DICIEMBRE 1992/JUNIO DE 12993. 3) PRESENCIA DE TRIATOMINOS EN EL SILAIS CENTRAL DE MANAGUA: OCTUBRE 1992/ENERO 1993. 4) EFICACIA TERAPEUTICA AL ESQUEÑA ANTIMALARICO CLASICO EN PACIENTES CON MALARIA POR EL P.FALCIPARUM EN EL HSOPITAL "JACINNTO HERNANDEZ", NUEVA GUINEA, CHONTALES NICARAGUA, 1992. 5) MANEJO DE PACIENTES CON MALARIA EN EL HOSPITAL REGIONAL "SANDINO" BLUEFILDS, NICARAGUA: 1987/1992. 6) CUMPLIMIENTO HOSPITALARIO DE LAS NORMAS DE CONTROL DE LA TUBERCULOSIS EN MANAGUA, NICARAGUA: 1991/1992. Se realizan a partir del desarrollo de las políticas nacionales de salud, basados en la descentralización de los programas específicos de prevención y control de la malaria y otras ETV y su integración a los SILOS, se identificó la necesidad de realizar un conjunto de actividades conteneidas en etapas cuyo objetivo es proporcionar los elementos dedesarrollo para la capacidad resolutiva de los servicios locales. Los estudios contenidos en el presente documento fueron realizados como parte de la cooperación de la Representación de OPS/OMS en Nicaragua y desarrollados técnicamente con el Programa Regionasl de Enfermedades transmisibles, en el marco del Proyecto de Cooperación OPS/ASDI para el control de la malaria y de otras enfermedades transmisibles.

Inmunodiagnóstico de la malaria en los niños / Malaria immunodiagnosis in children

Se estudiaron 55 niños con diagnóstico clínico y parasitoscópico de malaria, atendidos en los servicios de Parasitología, Infectología, Medicina Interna, Oncología, Nefrología, Hematología y Urgencias, del Instituto Nacional de Pediátria. A cada uno se le realizó detección de anticuerpos por el método de Inmunofluorescencia indirecta (IFI) usando antígeno de Plasmodium falciparum. El objeto del trabajo fue investigar la sensibilidad que tiene esta metodología para detectar y cuantificar anticuerpos específicos contra Plasmodium vivax y Plasmodium malariae. Se estudiaron dos grupos de pacientes: Grupo A constituído por 44 niños infectados con P. vivax, adquirido por picadura de Anopheles, en los que se demostraron títulos anticuerpos entre 1:20 y 1:1280; el mayor número de pacientes presentó títulos de 1:60 a 1:640. La sensibilidad fue del 100 por ciento. Grupo B conformado por 11 niños infectados por P.malariae, en los cuales el mecanismo de transmisión fue por transfusión de sangre. Se encontraron títulos de 1:20 ó más; la mayoría de pacientes presentaron títulos de 1:160 a 1:640. El porcentaje de positividad fue de 100. Se efectuaron retitulaciones posteriores al tratamiento, con objeto de evaluar su efectividad, observándose disminución o negativización de los títulos aproximadamente seis meses después. Se concluye que la inmunofluorescencia indirecta es un recurso de laboratorio útil para el inmunodiagnóstico de la malaria en los niños

Detection of circulating plasmodial antigens in human sera by sandwich ELISA with monoclonal antibodies.

Two monoclonal antibodies (MAbs), one produced against Plasmodium falciparum (PF-IG8) and the other against P. cynomolgi (PC-IE12) schizont antigens were used in a sandwich ELISA for the detection of circulating plasmodial antigens in sera of patients infected with either P. falciparum, P. vivax or P. malariae. The mean +/- SD optical density (OD) values for the normal control group using PF-108 and PC-1E12 were 0.351 +/- 0.036 and 0.205 +/- 0.044, respectively. Mean OD values for the three infected groups were found to be significantly higher than those of the normal control group for both MAbs. However, ELISA values for individual serum specimens did not correlate with the level of parasitemia in the infected blood. Using a cut-off point of mean OD +/- 3 SD of the normal control group as indicating a positive reading, the specificity of this assay with both MAbs was 100%. The sensitivity of the assay using PF-1G8 was 95% while that obtained with PC-1E12 was 98%.

Diffusion-in-gel enzyme-linked immunosorbent assay, ELISA and IFA test in the detection of malarial antibodies.

Malarial antibodies in 80 patients were measured using the diffusion-in-gel enzyme linked immunosorbent assay (DIG-ELISA), enzyme-linked immunosorbent assay (ELISA) and the indirect fluorescent antibody (IFA) test. Good correlations were obtained between all three tests in terms of sensitivity and reliability. DIG-ELISA has the advantage of being a rapid diagnostic tool for the detection of malarial antibodies.