Serologic responses of Korean soldiers serving in malaria-endemic areas during a recent outbreak of Plasmodium vivax.
Anti-Pv200 antibody levels were assessed in samples from endemic areas of Plasmodium vivax malaria in the Republic of Korea (ROK), using an indirect enzyme-linked immunosorbent assay (ELISA) method. Asymptomatic carriers of P. vivax were detected using nested polymerase chain reaction (PCR) of blood samples. Anti-Pv200 antibody levels in 20 vivax malaria patients (optical density +/- standard deviation [OD +/- SD] values 1.85 +/- 0.29 of IgG isotype and 1.33 +/- 1.33 of IgM isotype) were markedly higher than those of uninfected, malaria-naive controls (0.08 +/- 0.16 of IgG isotype and 0.04 +/- 0.04 of IgM isotype). Antibody levels for 7 out of 8 soldiers with a recent malaria infection were sustained above the cut-off values for 4 months after successful treatment. Analysis of serum collected from 40 healthy, asymptomatic soldiers who had a P. vivax malaria attack within 3 months after our sampling, revealed 11 antibody-positive samples (27.5%), compared to 5 positive samples (12.5%) collected from a random selection of 40 soldiers. Among a larger pool of 1,713 soldiers who had served in high-risk areas for P. vivax transmission, 15% were antibody positive. Among 1,000 blood samples from asymptomatic soldiers who had served in the high-risk areas, 4 samples (0.4%) were parasite positive, as determined by nested PCR. Our results show that anti-Pv200 antibody levels can provide useful information in the late diagnosis of P. vivax malaria infection in a previously naive population and also in large seroepidemiologic studies. Furthermore, our results suggest that asymptomatic P. vivax carriers could be important in the current outbreak of malaria in Korea.
Park
C G
CG
Korean Armed Forces Central Medical Research Institute, Chumok-dong, Yuseong-gu, Taejeon, Republic of Korea. parkc@mail.rockefeller.edu
Chwae
Y J
YJ
Kim
J I
JI
Lee
J H
JH
Hur
G M
GM
Jeon
B H
BH
Koh
J S
JS
Han
J H
JH
Lee
S J
SJ
Park
J W
JW
Kaslow
D C
DC
Strickman
D
D
Roh
C S
CS
D000818:Animals; D000913:Antibodies, Protozoan / Q000097:blood*; D000953:Antigens, Protozoan / Q000276:immunology; D000954:Antigens, Surface / Q000276:immunology; D002353:Carrier State / Q000469:parasitology; D016054:DNA, Protozoan / Q000032:analysis; D004196:Disease Outbreaks; D019353:Endemic Diseases; D006801:Humans; D007723:Korea / Q000453:epidemiology; D016780:Malaria, Vivax / Q000453:epidemiology* / Q000276:immunology* / Q000469:parasitology; D008889:Military Personnel; D010966:Plasmodium vivax / Q000235:genetics / Q000276:immunology* / Q000302:isolation & purification; D016133:Polymerase Chain Reaction / Q000379:methods; D015800:Protozoan Proteins / Q000276:immunology; D016036:Seroepidemiologic Studies
D000913:Antibodies, Protozoan; D000953:Antigens, Protozoan; D000954:Antigens, Surface; D016054:DNA, Protozoan; D015800:Protozoan Proteins; C041595:circumsporozoite protein, Protozoan; C073018:Pv200 antigen, P vivax