title: Genetic diversity and multiple infections of Plasmodium vivax malaria in Western Thailand.
abstract: Using two polymorphic genetic markers, the merozoite surface protein-3alpha (MSP-3alpha) and the circumsporozoite protein (CSP), we investigated the population diversity of Plasmodium vivax in Mae Sod, Thailand from April 2000 through June 2001. Genotyping the parasites isolated from 90 malaria patients attending two local clinics for the dimorphic CSP gene revealed that the majority of the parasites (77%) were the VK210 type. Genotyping the MSP3-alpha gene indicated that P. vivax populations exhibited an equally high level of polymorphism as those from Papua New Guinea, a hyperendemic region. Based on the length of polymerase chain reaction products, three major types of the MSP-3alpha locus were distinguished, with frequencies of 74.8%, 18.7%, and 6.5%, respectively. The 13 alleles distinguished by restriction fragment length polymorphism analysis did not show a significant seasonal variation in frequency. Genotyping the MSP-3alpha and CSP genes showed that 19.3% and 25.6% of the patients had multiple infections, respectively, and the combined rate was 35.6%. Comparisons of MSP-3alpha sequences from nine clones further confirmed the high level of genetic diversity of the parasite and also suggested that geographic isolation may exist. These results strongly indicate that P. vivax populations are highly diverse and multiple clonal infections are common in this malaria-hypoendemic region of Thailand.
authors.affiliation: Department of Entomology, Pennsylvania State University, University Park, Pennsylvania 16802, USA. luc2@psu.edu
authors.forename: Liwang
authors.initials: L
authors.lastname: Cui
authors.forename: Carlye N
authors.initials: CN
authors.lastname: Mascorro
authors.forename: Ql
authors.initials: Q
authors.lastname: Fan
authors.forename: Kimberly A
authors.initials: KA
authors.lastname: Rzomp
authors.forename: Benjawan
authors.initials: B
authors.lastname: Khuntirat
authors.forename: Guofa
authors.initials: G
authors.lastname: Zhou
authors.forename: Hong
authors.initials: H
authors.lastname: Chen
authors.forename: Guiyun
authors.initials: G
authors.lastname: Yan
authors.forename: Jetsumon
authors.initials: J
authors.lastname: Sattabongkot
mesh_terms: D000483:Alleles; D000595:Amino Acid Sequence; D000818:Animals; D000953:Antigens, Protozoan / Q000235:genetics; D001483:Base Sequence; D017124:Conserved Sequence; D017353:Gene Deletion; D005787:Gene Frequency; D005819:Genetic Markers; D014644:Genetic Variation; D005838:Genotype; D006801:Humans; D015994:Incidence; D016780:Malaria, Vivax / Q000453:epidemiology / Q000469:parasitology*; D010802:Phylogeny; D010966:Plasmodium vivax / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification; D016133:Polymerase Chain Reaction; D012150:Polymorphism, Restriction Fragment Length; D015995:Prevalence; D015800:Protozoan Proteins / Q000235:genetics; D012621:Seasons; D016415:Sequence Alignment; D013785:Thailand / Q000453:epidemiology
chemical_list: D000953:Antigens, Protozoan; D005819:Genetic Markers; D015800:Protozoan Proteins; C041595:circumsporozoite protein, Protozoan; C089133:merozoite surface protein 3, Plasmodium