Morphological atypia and molecular profile of Plasmodium vivax: Findings from an outbreak in the Brazilian Amazon

This study aimed to perform morphological and molecular analyses of parasites isolated from the blood of malaria-infected individuals during an outbreak in the Microregion of Cametá, State of Pará, Brazilian Amazon. A total of 260 positive samples were identified by microscopy as Plasmodium vivax; however, in three samples, forms considered unusual for the species were found and defined as morphological atypia of P. vivax. Single P. vivax infection was confirmed by qPCR in all samples. Among 256 genotyped samples, the VK247 genotype alone was identified in 255 samples, and the VK210 genotype was found in only one. The study showed that this malaria outbreak was caused by the etiological agent P. vivax, and for the first time, morphological atypia was described in isolates circulating in Brazil. Likewise, for the first time, the VK247 genotype was detected predominantly in single infections in an area of the State of Pará, which may suggest a greater circulation of the genotype in the region.