title: Seroprevalence of Antibodies against Plasmodium falciparum Sporozoite Antigens as Predictive Disease Transmission Markers in an Area of Ghana with Seasonal Malaria Transmission.
abstract: BACKGROUND
  As an increasing number of malaria-endemic countries approach the disease elimination phase, sustenance of control efforts and effective monitoring are necessary to ensure success. Mathematical models that estimate anti-parasite antibody seroconversion rates are gaining relevance as more sensitive transmission intensity estimation tools. Models however estimate yearly seroconversion and seroreversion rates and usually predict long term changes in transmission, occurring years before the time of sampling. Another challenge is the identification of appropriate antigen targets since specific antibody levels must directly reflect changes in transmission patterns. We therefore investigated the potential of antibodies to sporozoite and blood stage antigens for detecting short term differences in malaria transmission in two communities in Northern Ghana with marked, seasonal transmission.
  
  
  METHODS
  Cross-sectional surveys were conducted during the rainy and dry seasons in two communities, one in close proximity to an irrigation dam and the other at least 20 Km away from the dam. Antibodies against the sporozoite-specific antigens circumsporozoite protein (CSP) and Cell traversal for ookinetes and sporozoites (CelTOS) and the classical blood stage antigen apical membrane antigen 1 (AMA1) were measured by indirect ELISA. Antibody levels and seroprevalence were compared between surveys and between study communities. Antibody seroprevalence data were fitted to a modified reversible catalytic model to estimate the seroconversion and seroreversion rates.
  
  
  RESULTS
  Changes in sporozoite-specific antibody levels and seroprevalence directly reflected differences in parasite prevalence between the rainy and dry seasons and hence the extent of malaria transmission. Seroconversion rate estimates from modelled seroprevalence data did not however support the above observation.
  
  
  CONCLUSIONS
  The data confirms the potential utility of sporozoite-specific antigens as useful markers for monitoring short term/seasonal changes in malaria transmission. It may however be essential to update models to allow for assessment of seasonal changes in malaria transmission, which usually occur within four to six months.
authors.affiliation: Department of Immunology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Accra, Ghana.
authors.forename: Kwadwo A
authors.identifier: http://orcid.org/0000-0001-5483-9985
authors.initials: KA
authors.lastname: Kusi
authors.affiliation: Department of Biostatistics, School of Public Health, College of Health Sciences, University of Ghana, Legon, Accra, Ghana.
authors.forename: Samuel
authors.initials: S
authors.lastname: Bosomprah
authors.affiliation: Department of Immunology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Accra, Ghana.
authors.forename: Eric
authors.initials: E
authors.lastname: Kyei-Baafour
authors.affiliation: Department of Immunology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Accra, Ghana.
authors.forename: Emmanuel K
authors.initials: EK
authors.lastname: Dickson
authors.affiliation: Department of Immunology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Accra, Ghana.
authors.forename: Bernard
authors.initials: B
authors.lastname: Tornyigah
authors.affiliation: Malaria Vaccine Branch, Walter Reed Army Institute of Research, Silver Spring, MD, United States of America.
authors.forename: Evelina
authors.initials: E
authors.lastname: Angov
authors.affiliation: Malaria Vaccine Branch, Walter Reed Army Institute of Research, Silver Spring, MD, United States of America.
authors.forename: Sheetij
authors.initials: S
authors.lastname: Dutta
authors.affiliation: Department of Immunology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Accra, Ghana.
authors.forename: Daniel
authors.initials: D
authors.lastname: Dodoo
authors.affiliation: Malaria Department, Naval Medical Research Center, Silver Spring, MD, United States of America.
authors.forename: Martha
authors.initials: M
authors.lastname: Sedegah
authors.affiliation: Department of Epidemiology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Accra, Ghana.
authors.forename: Kwadwo A
authors.initials: KA
authors.lastname: Koram
mesh_terms: D000293:Adolescent; D000328:Adult; D000913:Antibodies, Protozoan / Q000276:immunology*; D000953:Antigens, Protozoan / Q000276:immunology*; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D005260:Female; D005869:Ghana / Q000453:epidemiology; D006801:Humans; D007223:Infant; D016778:Malaria, Falciparum / Q000453:epidemiology / Q000276:immunology / Q000635:transmission; D008297:Male; D008565:Membrane Proteins / Q000276:immunology*; D008954:Models, Biological; D010963:Plasmodium falciparum / Q000276:immunology*; D015800:Protozoan Proteins / Q000276:immunology*; D012621:Seasons; D016036:Seroepidemiologic Studies
chemical_list: D000913:Antibodies, Protozoan; D000953:Antigens, Protozoan; D008565:Membrane Proteins; D015800:Protozoan Proteins; C090077:apical membrane antigen I, Plasmodium