Reação de polimerização em cadeia (PCR) em etapa única para diagnóstico de Leishmania do subgênero (Viannia)

No Brasil, o principal agente etiológico da leishmaniose, apresentando freqüentemente comprometimento das mucosas, pertence ao subgênero (Viannia). A conduta terapêutica no tratamento da leishmaniose depende de seu diagnóstico parasitológico e os métodos clássicos restringem sua identificação. Neste trabalho, descrevemos uma reação de PCR, utilizando primers desenhados a partir de seqüências repetitivas de mini-exons, que amplificam um fragmento de 177pb e que são capazes de distinguir o subgênero (Viannia) do subgênero (Leishmania), tornando-se uma ferramenta útil no diagnóstico desta doença.In Brazil, the main etiologic agent of Leishmaniasis that frequently presents with mucosal involvement belongs to the Viannia subgenus. The therapeutic conduct in this disease depends on the parasitological diagnosis, and classical methods are restricted in identifying the agent. In this paper we describe a polymerase chain reaction (PCR), which uses primers designed from mini-exons repetitive sequences. The PCR amplifies a 177bp fragment that can distinguish (Viannia) from (Leishmania) subgenus. This test could be a useful diagnostic tool

Aspectos epidemiológicos e ecológicos relacionados à malária na área de influência do lago da Represa de Porto Primavera, região oeste do Estado de São Paulo, Brasil

A study was carried out in the area of influence of the Porto Primavera Hydroelectric Power Station, in western São Paulo State, to investigate ecological and epidemiological aspects of malaria in the area and monitor the profile of the anopheline populations following the environmental changes brought about by the construction of the lake. Mosquitoes captured were analyzed by standardized indicator species analysis (ISA) before and during different flooding phases (253 m and 257 m elevations). The local human population was studied by means of parasitological (thin/thick blood smears), molecular (PCR) and serological tests. Serological tests consisted of Enzyme Linked Immunosorbent Assay (ELISA) with synthetic peptides of the circumsporozoite protein (CSP) from classic Plasmodium vivax, P. vivax variants (VK247 and "vivax-like"), P. malariae and P. falciparum and Indirect Immunofluorescence Assay (IFA) with asexual forms of P. vivax, P. malariae and P. falciparum. The results of the entomological survey indicated that, although the Anopheles darlingi population increased after the flooding, the population density remained very low. No malaria, parasite infection or DNA was detected in the inhabitants of the study area. However, there was a low frequency of antibodies against asexual forms and a significant prevalence of antibodies against P. vivax, P. vivax variants, P. falciparum and P. malariae; the presence of these antibodies may result from recent or less recent contact with human or simian Plasmodium (a parallel study in the same area revealed the existence of a sylvatic cycle). Nevertheless, these results suggest that, as in other places where malaria is present and potential vectors circulate, the local epidemiological conditions observed could potentially support the transmission of malaria in Porto Primavera Lake if infected individuals are introduced in sufficient numbers. Further studies are required to elucidate the phenomena described in this paper.Foi realizada pesquisa na área de influência do lago da Usina Hidrelétrica de Porto Primavera, região oeste do Estado de São Paulo, para estudar aspectos ecológicos e epidemiológicos da malária na localidade e acompanhar o perfil das populações de anofelinos frente às mudanças decorrentes do impacto ambiental pela formação do lago. Mosquitos capturados foram analisados pelo Índice de Abundância de Espécies Padronizado (IAEP), antes e durante o enchimento do reservatório (cotas 253 e 257 m). A população humana local foi estudada por meio de teste parasitológico (gota espessa e esfregaço sangüíneo), testes moleculares (PCR) e testes sorológicos. A sorologia consistiu na reação de ELISA com peptídeos sintéticos correspondentes à porção repetitiva da proteína circumsporozoíta (CSP) de Plasmodium vivax clássico, e suas variantes VK247 e "vivax-like", P. malariae e P. falciparum; e reação de Imunofluorescência Indireta (RIFI) com formas assexuadas de P. vivax, P. malariae e P. falciparum. Os resultados do estudo entomológico indicaram que, embora a população de Anopheles darlingi tenha aumentando após o enchimento, permaneceu em baixa densidade. Não foi detectada malária nem a presença de parasitos ou de DNA parasitário nos habitantes estudados. No entanto, foi observada baixa freqüência de anticorpos contra formas assexuadas e significativa prevalência de anticorpos contra esporozoítos de P. vivax e suas variantes, P. falciparum e P. malariae, que poderiam decorrer de contatos prévios, recentes ou não, com plasmódios humanos ou símios (o ciclo silvestre foi evidenciado em estudo paralelo realizado na mesma área). Por outro lado, estes resultados sugerem que, como em outros lugares onde existem vetores potenciais da malária, as condições epidemiológicas poderiam potencialmente permitir a transmissão da malária na área de influência do lago de Porto Primavera, se indivíduos infectados fossem introduzidos em número suficiente. Estudos adicionais deverão ser realizados para elucidar os fenômenos relatados neste artigo

Epidemiology of Disappearing Plasmodium vivax Malaria: A Case Study in Rural Amazonia

Background: New frontier settlements across the Amazon Basin pose a major challenge for malaria elimination in Brazil. Here we describe the epidemiology of malaria during the early phases of occupation of farming settlements in Remansinho area, Brazilian Amazonia. We examine the relative contribution of low-density and asymptomatic parasitemias to the overall Plasmodium vivax burden over a period of declining transmission and discuss potential hurdles for malaria elimination in Remansinho and similar settings. Methods: Eight community-wide cross-sectional surveys, involving 584 subjects, were carried out in Remansinho over 3 years and complemented by active and passive surveillance of febrile illnesses between the surveys. We used quantitative PCR to detect low-density asexual parasitemias and gametocytemias missed by conventional microscopy. Mixed-effects multiple logistic regression models were used to characterize independent risk factors for P. vivax infection and disease. Principal Findings/Conclusions P. vivax prevalence decreased from 23.8% (March–April 2010) to 3.0% (April–May 2013), with no P. falciparum infections diagnosed after March–April 2011. Although migrants from malaria-free areas were at increased risk of malaria, their odds of having P. vivax infection and disease decreased by 2–3% with each year of residence in Amazonia. Several findings indicate that low-density and asymptomatic P. vivax parasitemias may complicate residual malaria elimination in Remansinho: (a) the proportion of subpatent infections (i.e. missed by microscopy) increased from 43.8% to 73.1% as P. vivax transmission declined; (b) most (56.6%) P. vivax infections were asymptomatic and 32.8% of them were both subpatent and asymptomatic; (c) asymptomatic parasite carriers accounted for 54.4% of the total P. vivax biomass in the host population; (d) over 90% subpatent and asymptomatic P. vivax had PCR-detectable gametocytemias; and (e) few (17.0%) asymptomatic and subpatent P. vivax infections that were left untreated progressed to clinical disease over 6 weeks of follow-up and became detectable by routine malaria surveillance

Relationship between acute malaria and anti-resa antibodies in sera of patients from two different endemic areas in Brazil

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Instituto de Medicina Tropical de São PauloCompanhia Florestal de Monte DouradoEscola Paulista de MedicinaInstituto de Ciências Biomédicas Depto. de ParasitologiaUNIFESP, EPMSciEL

Clustering symptoms of non-severe malaria in semi-immune Amazonian patients

Malaria is a disease that generates a broad spectrum of clinical features. The purpose of this study was to evaluate the clinical spectrum of malaria in semi-immune populations. Patients were recruited in Mâncio Lima, a city situated in the Brazilian Amazon region. The study included 171 malaria cases, which were diagnosed via the use of a thick blood smear and confirmed by molecular methods. A questionnaire addressing 19 common symptoms was administered to all patients. Multiple correspondence analysis and hierarchical cluster analysis were performed to identify clusters of symptoms, and logistic regression was used to identify factors associated with the occurrence of symptoms. The cluster analysis revealed five groups of symptoms: the first cluster, which included algic- and fever-related symptoms, occurred in up to 95.3% of the cases. The second cluster, which comprised gastric symptoms (nausea, abdominal pain, inappetence, and bitter mouth), occurred in frequencies that ranged between 35.1% and 42.7%, and at least one of these symptoms was observed in 71.9% of the subjects. All respiratory symptoms were clustered and occurred in 42.7% of the malaria cases, and diarrhea occurred in 9.9% of the cases. Symptoms constituting the fifth cluster were vomiting and pallor, with a 14.6% and 11.7% of prevalence, respectively. A higher parasitemia count (more than 300 parasites/mm3) was associated with the presence of fever, vomiting, dizziness, and weakness (P < 0.05). Arthralgia and myalgia were associated with patients over the age of 14 years (P < 0.001). Having experienced at least eight malaria episodes prior to the study was associated with a decreased risk of chills and fever and an increased risk of sore throat (P < 0.05). None of the symptoms showed an association with gender or with species of Plasmodium. The clinical spectrum of malaria in semi-immune individuals can have a broad range of symptoms, the frequency and intensity of which are associated with age, past exposure to malaria, and parasitemia. Understanding the full spectrum of nonsevere malaria is important in endemic areas to guide both passive and active case detection, for the diagnosis of malaria in travelers returning to non-endemic areas, and for the development of vaccines aimed to decrease symptom severity

Single step polymerase chain reaction (PCR) for the diagnosis of the Leishmania (Viannia) subgenus Reação de polimerização em cadeia (PCR) em etapa única para diagnóstico de Leishmania do subgênero (Viannia)

In Brazil, the main etiologic agent of Leishmaniasis that frequently presents with mucosal involvement belongs to the Viannia subgenus. The therapeutic conduct in this disease depends on the parasitological diagnosis, and classical methods are restricted in identifying the agent. In this paper we describe a polymerase chain reaction (PCR), which uses primers designed from mini-exons repetitive sequences. The PCR amplifies a 177bp fragment that can distinguish (Viannia) from (Leishmania) subgenus. This test could be a useful diagnostic tool.<br>No Brasil, o principal agente etiológico da leishmaniose, apresentando freqüentemente comprometimento das mucosas, pertence ao subgênero (Viannia). A conduta terapêutica no tratamento da leishmaniose depende de seu diagnóstico parasitológico e os métodos clássicos restringem sua identificação. Neste trabalho, descrevemos uma reação de PCR, utilizando primers desenhados a partir de seqüências repetitivas de mini-exons, que amplificam um fragmento de 177pb e que são capazes de distinguir o subgênero (Viannia) do subgênero (Leishmania), tornando-se uma ferramenta útil no diagnóstico desta doença