title: Unusual plasmodium malariae-like parasites in southeast Asia.
abstract: 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.
authors.affiliation: Department of International Health, Nagoya University School of Medicine, Japan. hiko@med.nagoya-u.ac.jp
authors.forename: Fumihiko
authors.initials: F
authors.lastname: Kawamoto
authors.forename: Thin Thida
authors.initials: TT
authors.lastname: Win
authors.forename: Sahoko
authors.initials: S
authors.lastname: Mizuno
authors.forename: Khin
authors.initials: K
authors.lastname: Lin
authors.forename: Ohn
authors.initials: O
authors.lastname: Kyaw
authors.forename: Indah S
authors.initials: IS
authors.lastname: Tantulart
authors.forename: Daniel P
authors.initials: DP
authors.lastname: Mason
authors.forename: Masatsugu
authors.initials: M
authors.lastname: Kimura
authors.forename: Chansuda
authors.initials: C
authors.lastname: Wongsrichanalai
mesh_terms: D000818:Animals; D001483:Base Sequence; D016054:DNA, Protozoan / Q000737:chemistry / Q000235:genetics*; D006801:Humans; D008288:Malaria / Q000097:blood / Q000469:parasitology*; D008969:Molecular Sequence Data; D002052:Myanmar; D009693:Nucleic Acid Hybridization; D010965:Plasmodium malariae / Q000145:classification* / Q000166:cytology / Q000235:genetics; D016133:Polymerase Chain Reaction; D015800:Protozoan Proteins / Q000737:chemistry / Q000235:genetics; D012335:RNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D012424:Rural Population; D012689:Sequence Homology, Nucleic Acid
chemical_list: D016054:DNA, Protozoan; D015800:Protozoan Proteins; D012335:RNA, Ribosomal; C041595:circumsporozoite protein, Protozoan