title: Co-infections of Plasmodium knowlesi, P. falciparum, and P. vivax among Humans and Anopheles dirus Mosquitoes, Southern Vietnam.
abstract: A single Anopheles dirus mosquito carrying sporozoites of Plasmodium knowlesi, P. falciparum, and P. vivax was recently discovered in Khanh Phu, southern Vietnam. Further sampling of humans and mosquitoes in this area during 2009-2010 showed P. knowlesi infections in 32 (26%) persons with malaria (n = 125) and in 31 (43%) sporozoite-positive An. dirus mosquitoes (n = 73). Co-infections of P. knowlesi and P. vivax were predominant in mosquitoes and humans, while single P. knowlesi infections were found only in mosquitoes. P. knowlesi-co-infected patients were largely asymptomatic and were concentrated among ethnic minority families who commonly spend nights in the forest. P. knowlesi carriers were significantly younger than those infected with other malaria parasite species. These results imply that even if human malaria could be eliminated, forests that harbor An. dirus mosquitoes and macaque monkeys will remain a reservoir for the zoonotic transmission of P. knowlesi.
authors.affiliation: Medical Committee Netherlands-Vietnam, Khanh Hoa Province, Vietnam. ronmarch@gmail.com
authors.forename: Ron P
authors.initials: RP
authors.lastname: Marchand
authors.forename: Richard
authors.initials: R
authors.lastname: Culleton
authors.forename: Yoshimasa
authors.initials: Y
authors.lastname: Maeno
authors.forename: Nguyen Tuyen
authors.initials: NT
authors.lastname: Quang
authors.forename: Shusuke
authors.initials: S
authors.lastname: Nakazawa
mesh_terms: D000328:Adult; D000818:Animals; D000852:Anopheles / Q000469:parasitology*; D016172:DNA Fingerprinting; D004197:Disease Reservoirs / Q000469:parasitology; D005260:Female; D006801:Humans; D007303:Insect Vectors / Q000469:parasitology; D008251:Macaca; D016778:Malaria, Falciparum / Q000097:blood / Q000150:complications / Q000208:ethnology / Q000469:parasitology / Q000635:transmission; D016780:Malaria, Vivax / Q000097:blood / Q000150:complications / Q000208:ethnology / Q000469:parasitology / Q000635:transmission; D008297:Male; D008853:Microscopy; D010963:Plasmodium falciparum / Q000302:isolation & purification* / Q000502:physiology; D016790:Plasmodium knowlesi / Q000302:isolation & purification* / Q000502:physiology; D010966:Plasmodium vivax / Q000302:isolation & purification* / Q000502:physiology; D016133:Polymerase Chain Reaction; D012337:RNA, Ribosomal, 18S / Q000032:analysis; D012469:Salivary Glands / Q000469:parasitology; D034101:Sporozoites; D014744:Vietnam / Q000453:epidemiology
chemical_list: D012337:RNA, Ribosomal, 18S