title: Comparison of the antibody responses to Plasmodium vivax and Plasmodium falciparum antigens in residents of Mandalay, Myanmar.
abstract: BACKGROUND
  The aim of this study was to investigate the profile of antibodies against several antigens of Plasmodium vivax and Plasmodium falciparum in Mandalay, Myanmar.
  
  
  METHODS
  Malaria parasites were identified by microscopic examination. To test the antibodies against P. vivax and P. falciparum in sera, an indirect immunofluorescence antibody test (IFAT) was performed using asexual blood parasite antigens. An enzyme-linked immunosorbent assay (ELISA) was performed with circumsporozoite protein (CSP), Pvs25 and Pvs28 recombinant proteins of transmission-blocking vaccine candidates for P. vivax, and liver stage specific antigen-1 and -3 (PfLSA-1, PfLSA-3) for P. falciparum.
  
  
  RESULTS
  Fourteen patients among 112 were found to be infected with P. vivax and 26 with P. falciparum by thick smear examination. Twenty-three patients were found to be infected with P. vivax, 19 with P. falciparum and five with both by thin smear examination. Blood samples were divided into two groups: Group I consisted of patients who were positive for infection by microscopic examination, and Group II consisted of those who showed symptoms, but were negative in microscopic examination. In P. falciparum, IgG against the blood stage antigen in Group I (80.8%) was higher than in Group II (70.0%). In P. vivax, IgG against the blood stage antigen in Group I (53.8%) was higher than in Group II (41.7%). However, the positivity rate of the PvCSP VK210 subtype in Group II (40.0%) was higher than in Group I (23.1%). Similarly for the PvCSP VK247 subtype, Group II (21.7%) was higher than that for Group I (9.6%). A similar pattern was observed in the ELISA using Pvs25 and Pvs28: positive rates of Group II were higher than those for Group I. However, those differences were not shown significant in statistics.
  
  
  CONCLUSIONS
  The positive rates for blood stage antigens of P. falciparum were higher in Group I than in Group II, but the positive rates for antigens of other stages (PfLSA-1 and -3) showed opposite results. Similar to P. falciparum, the positive rate of pre-blood stage (CSP VK210 and 247 subtype) and post-blood stage (Pvs25 and 28) antigens of P. vivax were higher in Group II than in Group I. Therefore, sero-diagnosis is not helpful to discriminate between malaria patients and symptomatic individuals during the epidemic season in Myanmar.
authors.affiliation: Department of Parasitology, College of Medicine, Inha University, Incheon405-751, Republic of Korea.
authors.forename: Tong-Soo
authors.initials: TS
authors.lastname: Kim
authors.forename: Hyung-Hwan
authors.initials: HH
authors.lastname: Kim
authors.forename: Jung-Yeon
authors.initials: JY
authors.lastname: Kim
authors.forename: Yoon
authors.initials: Y
authors.lastname: Kong
authors.forename: Byoung-Kuk
authors.initials: BK
authors.lastname: Na
authors.forename: Khin
authors.initials: K
authors.lastname: Lin
authors.forename: Sung-Ung
authors.initials: SU
authors.lastname: Moon
authors.forename: Yeon-Joo
authors.initials: YJ
authors.lastname: Kim
authors.forename: Myoung-Hee
authors.initials: MH
authors.lastname: Kwon
authors.forename: Youngjoo
authors.initials: Y
authors.lastname: Sohn
authors.forename: Hyuck
authors.initials: H
authors.lastname: Kim
authors.forename: Hyeong-Woo
authors.initials: HW
authors.lastname: Lee
mesh_terms: D000913:Antibodies, Protozoan / Q000097:blood*; D000953:Antigens, Protozoan; D004797:Enzyme-Linked Immunosorbent Assay; D019084:Fluorescent Antibody Technique, Indirect; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D016778:Malaria, Falciparum / Q000175:diagnosis*; D016780:Malaria, Vivax / Q000175:diagnosis*; D008853:Microscopy; D002052:Myanmar; D010963:Plasmodium falciparum / Q000276:immunology*; D010966:Plasmodium vivax / Q000276:immunology*; D012680:Sensitivity and Specificity
chemical_list: D000913:Antibodies, Protozoan; D000953:Antigens, Protozoan; D007074:Immunoglobulin G