title: Marked age-dependent prevalence of symptomatic and patent infections and complexity of distribution of human Plasmodium species in central Vietnam.
abstract: In Vietnam, Plasmodium falciparum and P. vivax are responsible for most malaria infections, and P. malariae and P. ovale infections are rarely reported. Nevertheless, species-specific polymerase chain reaction analysis on 2,303 blood samples collected during a cross-sectional survey conducted in a forest area of central Vietnam identified 223 (9.7%) P. falciparum, 170 (7.4%) P. vivax, 95 (4.1%) P. malariae, and 19 (0.8%) P. ovale mono-infections and 164 (7.1%) mixed infections. Of the 671 Plasmodium-positive samples by polymerase chain reaction, only 331 were detected by microscopy. Microscopy poorly diagnosed P. malariae, P. ovale, and mixed infections. Clinical and sub-clinical infections occurred in all age groups. The risk for infection and disease decreased with age, probably because of acquired partial immunity. The common occurrence of sub-patent infections seems to indicate that the malaria burden is underestimated and that diagnostic and therapeutic policies should be adapted accordingly.
authors.forename: Hong Van
authors.initials: HV
authors.lastname: Nguyen
authors.forename: Peter van den
authors.initials: PVD
authors.lastname: Eede
authors.forename: Chantal
authors.initials: C
authors.lastname: van Overmeir
authors.forename: Ngo Duc
authors.initials: ND
authors.lastname: Thang
authors.forename: Le Xuan
authors.initials: LX
authors.lastname: Hung
authors.forename: Umberto
authors.initials: U
authors.lastname: D'Alessandro
authors.forename: Annette
authors.initials: A
authors.lastname: Erhart
mesh_terms: D000293:Adolescent; D000328:Adult; D000375:Aging; D002648:Child; D002675:Child, Preschool; D006801:Humans; D007223:Infant; D008288:Malaria / Q000453:epidemiology / Q000469:parasitology*; D015999:Multivariate Analysis; D010961:Plasmodium / Q000145:classification* / Q000235:genetics; D016133:Polymerase Chain Reaction; D015995:Prevalence; D012307:Risk Factors; D013045:Species Specificity; D014744:Vietnam / Q000453:epidemiology; D055815:Young Adult