Mixed Plasmodium falciparum infections and its clinical implications in four areas of the Brazilian Amazon region

Lorenzetti, Alexandre; Fornazari, Patrícia Aparecida; Bonini-Domingos, Ana C.; Penhalbel, Roberta de Souza Rodrigues; Fugikaha, Érika; Bonini-Domingos, Cláudia Regina; Fraga, Valéria Daltibari; Conceição, Luciana Moran; Rossit, Andréa Regina Baptista; Cavasini, Carlos Eugênio; Couto, Vanja Suely Calvosa D’Almeida; Machado, Ricardo Luiz Dantas

doi:10.1016/j.actatropica.2008.03.012

Cited by 19 publications

(16 citation statements)

References 37 publications

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“…Mixed infections have been reported in other diseases caused by different protozoans. In cases of malaria, up to 27.0% (Lorenzetti et al 2008) of mixed infections have been verified in certain areas, demonstrating the coexistence of two species ( Plasmodium falciparum and Plasmodium vivax ) which contributes to increased virulence, transmissibility, and resistance to drugs due to intrahost competition (Havyliuk and Ferreira, 2009). …”

Section: Discussionmentioning

confidence: 99%

Characterization of Leishmania spp. causing cutaneous leishmaniasis in Manaus, Amazonas, Brazil

et al. 2010

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In the State of Amazonas, American tegumentary leishmaniasis is endemic and presents a wide spectrum of clinical variability due to the large diversity of circulating species in the region. Isolates from patients in Manaus and its metropolitan region were characterized using monoclonal antibodies and isoenzymes belonging to four species of the parasite: Leishmania (Viannia) guyanensis, 73% (153/209); Leishmania (Viannia) braziliensis, 14% (30/209); Leishmania (Leishmania) amazonensis, 8% (17/209); and Leishmania (Viannia) naiffii, 4% (9/209). The most prevalent species was L. (V.) guyanensis. The principal finding of this study was the important quantity of infections involving more than one parasite species, representing 14% (29/209) of the total. The findings obtained in this work regarding the parasite are further highlighted by the fact that these isolates were obtained from clinical samples collected from single lesions.

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Section: Discussionmentioning

confidence: 99%

Characterization of Leishmania spp. causing cutaneous leishmaniasis in Manaus, Amazonas, Brazil

et al. 2010

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“…Nevertheless, the biphasic curve analysis can predict with reasonable accuracy the relative compositions of parasite subpopulations within a given sample. The occurrence of mixed infections has profound implications in clinical testing (21,40,42). This analysis can also be tailored to populations that have more than two types of strains, resulting in triphasic or even quadriphasic curves.…”

Section: Discussionmentioning

confidence: 99%

“…Other groups have noted that a number of malarial infections are heterogeneous in their composition (21,40). In fact, almost all infections occurring in nature are mixed, requiring a method that can discern subtle changes in resistance patterns.…”

Section: Discussionmentioning

confidence: 99%

Assessment of Malaria In Vitro Drug Combination Screening and Mixed-Strain Infections Using the Malaria Sybr Green I-Based Fluorescence Assay

Dennull

Reinbold

et al. 2009

Antimicrob Agents Chemother

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Several drug development strategies, including optimization of new antimalarial drug combinations, have been used to counter malaria drug resistance. We evaluated the malaria Sybr green I-based fluorescence (MSF) assay for its use in in vitro drug combination sensitivity assays. Drug combinations of previously published synergistic (atovaquone and proguanil), indifferent (chloroquine and azithromycin), and antagonistic (chloroquine and atovaquone) antimalarial drug interactions were tested against Plasmodium falciparum strains D6 and W2 using the MSF assay. Fifty percent inhibitory concentrations (IC 50 s) were calculated for individual drugs and in fixed ratio combinations relative to their individual IC 50 s. Subsequent isobologram analysis and fractional inhibitory concentration determinations demonstrated the expected drug interaction pattern for each combination tested. Furthermore, we explored the ability of the MSF assay to examine mixed parasite population dynamics, which are commonly seen in malaria patient isolates. Specifically, the capacity of the MSF assay to discern between single and mixed parasite populations was determined. To simulate mixed infections in vitro, fixed ratios of D6 and W2 strains were cocultured with antimalarial drugs and IC 50 s were determined using the MSF assay. Dichotomous concentration curves indicated that the sensitive and resistant parasites composing the genetically heterogeneous population were detectable. Biphasic analysis was performed to obtain subpopulation IC 50 s for comparison to those obtained for the individual malaria strains alone. In conclusion, the MSF assay allows for reliable antimalarial drug combination screening and provides an important method to discern between homogenous and heterogeneous parasite populations.

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“…plasmódio) e de infecções mistas 13 . Desde 1990, vários estudos Desde 1990, vários estudos têm ressaltado a aplicação da reação em cadeia da polimerase (polymerase-chain reaction -PCR) no diagnóstico molecular da malária 12 26 , nos inquéritos epidemiológicos 28 30 , no rastreamento de doadores infectados em bancos de sangue 27 , na determinação do portador assintomático de plasmódio 1 29 e no monitoramento da resposta terapêutica 5 .…”

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Diagnóstico molecular da malária em uma unidade de atenção terciária na Amazônia Brasileira

Costa

Vieira

Ferreira

et al. 2008

Rev. Soc. Bras. Med. Trop.

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O exame de rotina para o diagnóstico da malária continua sendo a gota espessa, apesar da comprovada diminuição da sensibilidade e especificidade em situações de densidade parasitária baixa e infecções mistas. A reação em cadeia da polimerase vem sendo cada vez mais utilizada para a detecção molecular e identificação das espécies de plasmódio, por apresentar maior sensibilidade e especificidade. Foi realizada a nested-PCR em amostras de sangue total de 344 pacientes com síndrome febril aguda que se apresentaram para o diagnóstico de malária, em uma unidade terciária de saúde, em Manaus (Amazonas). Nenhum caso de malária por Plasmodium malariae foi diagnosticado à gota espessa ou PCR. Observou-se co-positividade de 96,7%, co-negatividade de 62,2% e coeficiente kappa de 0,44 entre PCR e gota espessa para Plasmodium falciparum. Para Plasmodium vivax, co-positividade de 100%, co-negatividade de 78,1% e coeficiente kappa de 0,56. Na detecção da malária mista, co-positividade de 100%, co-negatividade de 84,9% e coeficiente kappa de 0,26. A reação em cadeia da polimerase detectou alto número de infecções mistas nas amostras analisadas, mas seu uso rotineiro no diagnóstico da malária merece ainda ampla discussão.

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Mixed Plasmodium falciparum infections and its clinical implications in four areas of the Brazilian Amazon region

Cited by 19 publications

References 37 publications

Characterization of Leishmania spp. causing cutaneous leishmaniasis in Manaus, Amazonas, Brazil

Characterization of Leishmania spp. causing cutaneous leishmaniasis in Manaus, Amazonas, Brazil

Assessment of Malaria In Vitro Drug Combination Screening and Mixed-Strain Infections Using the Malaria Sybr Green I-Based Fluorescence Assay

Diagnóstico molecular da malária em uma unidade de atenção terciária na Amazônia Brasileira

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