Introduction: Malaria caused by Plasmodium vivax species has shown signs of severity, recorded with increasing frequency in the medical literature. This study aimed to characterize the signs of severe malaria by Plasmodium vivax in the State of Maranhão, Brazil. Methods: A descriptive cohort study of patients assisted in the field and a historical and concurrent study of a series of cases among hospitalized patients were undertaken to identify the clinical and laboratory signs of severity. Results: A total of 153 patients were included in the study, 13 of whom were hospitalized. Males made up the majority, numbering 103 (67.3%). The age of the patients ranged from 10 to 70 years, 92.2% were natives of the State of Maranhão, and 65% of the patients had had malaria before. The average time elapsed between symptom onset and diagnosis among outpatients was three days, while among hospitalized patients this average reached 15.5 days, a statistically significant difference (p=0.001). The parasitemia ranged from 500 to 10,000 parasites/µl in 92.8% of cases. The clinical and laboratory manifestations of severity were vomiting and diarrhea, jaundice, drowsiness, mental confusion, seizures, loss of consciousness, agitation, bleeding, pale skin, coughing and dyspnea, thrombocytopenia, anemia, elevation of nitrogenous compounds, and elevated transaminases and bilirubin. Conclusions: The monitoring of malaria patients with Plasmodium vivax showed the possibility of aggravation, the intensity of which varied in different circumstances, especially the interval time between falling ill and diagnostic confirmation.

ARTIGO/ARTICLEVariações no gene da proteína circunsporozoíta (CSP) da espécie Plasmodium vivax foram reveladas por estudos realizados nas últimas décadas 13 15 . A primeira variante seqüenciada e que se caracteriza pela presença de um nonapeptídeo repetido em tandem no domínio central da proteína, foi denominada VK210, considerada a forma clássica de Plasmodium vivax. Em cepas da Tailândia foram descritas variações no referido nonapeptídeo, sendo essa variante conhecida como VK247 15 . Posteriormente, em Papua Nova Guiné, foi relatada a existência de uma variante denominada Plasmodium vivax-like, por ser morfologicamente semelhante ao Plasmodium vivax, mas por diferir na seqüência repetitiva da região central da CSP, bem como por induzir resposta ABSTRACTThis study was developed with the aim of characterizing Plasmodium vivax circumsporozoite protein genotypes on the Island of São Luís, Maranhão. Blood samples were taken for direct parasitological examination (thick blood film) from 126 individuals. Among these individuals, 109 samples were also taken for molecular diagnosis by means of the polymerase chain reaction. The parasitological examination showed the presence of Plasmodium vivax in two symptomatic individuals, while the molecular study was positive for Plasmodium vivax in seven individuals (two symptomatic and positive from the thick blood film and five asymptomatic and negative from the thick blood film). Two samples showed an association with Plasmodium falciparum. Genotyping of the Plasmodium vivax samples showed that the VK 210 variant was present. This was associated with the VK 247 variant in two samples. A transmissão desta espécie, num padrão endêmico, na Ilha de São Luís, motivou o desenvolvimento do estudo que teve por objetivo caracterizar os genótipos da proteína circunsporozoíta do Plasmodium vivax e, portanto, as variantes da espécie. Além disso, propôs-se a comparação de métodos microscópicos e Key