Unusual Plasmodium malariae-like parasites in Southeast Asia

Fumihiko Kawamoto, Thin Thida Win, Sahoko Mizuno, Khin Lin, Ohn Kyaw, Indah S. Tantular, Daniel P. Mason, Masatsugu Kimura, Chansuda Wongsrichanalai

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24 Citations (Scopus)


During malaria surveys in Myanmar, 2 peculiar forms of Plasmodium malariae-like parasites were found. The morphologies of their early trophozoite stages were distinct from that of the typical P. malariae, resembling instead that of Plasmodium vivax, var. minuta, reported by Emin, and Plasmodium tenue, reported by Stephens, both in 1914. Two polymerase chain reaction (PCR)-based diagnoses, which target the same regions in the small subunit ribosomal RNA (SSUrRNA) genes, indicated that these parasites were new variant forms of P. malariae and that they could be separated into 2 genetic types that correlated with the 2 morphological types. Sequence analysis of the SSUrRNA and the circumsporozoite protein genes revealed that they were distinct both from each other and from other known P. malariae isolates and that the P. tenue-like type was closer to a monkey quartan malaria parasite, Plasmodium brasilianum. These results illustrate that the microscopic appearance of human P. malariae parasites may be more varied than previously assumed and suggest the value of molecular tools in the evaluation of malaria morphological variants.

Original languageEnglish
Pages (from-to)350-357
Number of pages8
JournalJournal of Parasitology
Issue number2
Publication statusPublished - 2002
Externally publishedYes


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