RESUMO
Malaria, a major global public health problem, is mainly caused by Plasmodium falciparum and Plasmodium vivax, and is responsible for nearly half a million deaths annually. Although P. vivax malaria was not believed to cause severe disease, recent robust studies have proved otherwise. However, the clinical spectrum and pathogenesis of severe vivax malaria and, especially, its respiratory complications remain poorly understood. A systematic search for articles reporting respiratory complications associated with vivax malaria was performed in Lilacs, Cochrane, Scielo, Web of Science, and Medline databases irrespective of publication date. Prevalence of acute respiratory distress syndrome (ARDS) and associated mortality among vivax patients were calculated from cross-sectional and longitudinal studies, whereas factors associated with mortality were calculated from data pooled from case reports and series of cases. A total of 101 studies were included (49 cross-sectional or longitudinal and 52 case reports or series of cases). Prevalence of ARDS was 2.8% and 2.2% in children and adults, respectively, with nearly 50% mortality. Moreover, female sex (P = 0.013), having any comorbidity (P = 0.036), lower body temperature (P = 0.032), lower hemoglobin (P = 0.043), and oxygen saturation (P = 0.053) values were significantly associated with mortality. Plasmodium vivax malaria respiratory complications included ARDS and were associated with high mortality. Demographics and clinical characteristics upon presentation to hospital were associated with mortality among patients with respiratory complications in vivax malaria. This study reaffirms the evidence of severe and fatal complications of P. vivax malaria and its associated respiratory complications.
Assuntos
Malária Vivax/complicações , Doenças Respiratórias/etiologia , Saúde Global , Humanos , Malária Vivax/epidemiologia , Malária Vivax/mortalidade , Doenças Respiratórias/epidemiologia , Doenças Respiratórias/mortalidadeRESUMO
It is generally accepted that Plasmodium vivax, the most widely distributed human malaria parasite, causes mild disease and that this species does not sequester in the deep capillaries of internal organs. Recent evidence, however, has demonstrated that there is severe disease, sometimes resulting in death, exclusively associated with P. vivax and that P. vivax-infected reticulocytes are able to cytoadhere in vitro to different endothelial cells and placental cryosections. Here, we review the scarce and preliminary data on cytoadherence in P. vivax, reinforcing the importance of this phenomenon in this species and highlighting the avenues that it opens for our understanding of the pathology of this neglected human malaria parasite.
Assuntos
Humanos , Eritrócitos , Malária Vivax , Plasmodium vivax , Adesão Celular , Eritrócitos/fisiologia , Malária Vivax/patologia , Plasmodium vivax/fisiologiaRESUMO
We cloned and characterized a Plasmodium vivax repeat element of 7872bp named PvRE7.8. Several internal tandem repeats were found along the sequence. The repetitive nature of the PvRE7.8 element was confirmed by hybridization of a P. vivax YAC library. Based on the data bank analysis and the presence of two contiguous putative genes that may encode proteins related to DNA metabolism, PvRE7.8 could be considered an inactivated transposon-LINE element. By using Pv79 as probe or primers derived from Pv79-flanking sequences, P. vivax DNA Could be detected from whole blood and mosquito samples. We consider that the repeat element described here has potential for P. vivax malaria diagnosis and for epidemiological analysis of P. vivax transmission areas.
Assuntos
DNA de Protozoário/química , Sequências Repetitivas Dispersas/genética , Malária Vivax/parasitologia , Plasmodium vivax/genética , Aedes/parasitologia , Sequência de Aminoácidos , Animais , Sequência de Bases , Clonagem Molecular , Culex/parasitologia , Sondas de DNA/química , DNA de Protozoário/isolamento & purificação , Eletroforese em Gel de Ágar , Humanos , Immunoblotting , Malária Vivax/diagnóstico , Malária Vivax/epidemiologia , Dados de Sequência Molecular , Plasmodium vivax/isolamento & purificação , Reação em Cadeia da Polimerase , Proteínas de Protozoários/química , Proteínas de Protozoários/genética , Alinhamento de SequênciaRESUMO
BACKGROUND: Cytoadherence and rosetting contribute to the development of severe Plasmodium falciparum malaria. In Brazil,severe falciparum malaria is mostly associated with renal or pulmonary complications and very rarely with cerebral malaria. The most N-terminal DBL1 alpha domain of PfEMP1, a protein encoded by the var multigene family mediates rosetting. We analyzed parasites of Brazilian patients with severe malaria to determine whether there were particular DBL1 alpha var sequences predominantly expressed in such patients. MATERIALS AND METHODS: DBL1 alpha var sequences were obtained from parasites of Brazilian patients with severe and mild malaria and were analyzed by standard bioinformatic programs. Three hundred twenty var DBL1 alpha sequences obtained from 80 Brazilian patients with mild malaria were spotted in high-density filters and hybridized to probes representing predominantly expressed sequences in parasites from patients with severe malaria. A DBL1 alpha domain was expressed in bacteria and used to demonstrate its binding capacity to erythrocytes by immunofluorescence. RESULTS: Forty-three different and unreported DBL1 alpha amino acid sequences were obtained. Sequences predominantly expressed in patients with severe malaria could be subgrouped due to deletions of 1-2-cysteine residues. These sequences were commonly found in the var gene repertoire of parasites from patients with mild malaria, yet they were rarely expressed in these patients. A recombinant protein representing the most abundantly expressed sequence detected in one patient with severe malaria bound directly to uninfected erythrocytes. CONCLUSIONS: This is the first report showing an association of severe noncerebral malaria from Brazil with particular DBL1 alpha sequences.