title: Anti-malarial seroprevalence assessment during an elimination programme in Chabahar District, south-eastern Iran.
abstract: Iran has achieved a substantial decline in malaria incidence over the past decades. A common feature of malaria-endemic settings is the requirement for more sensitive techniques to describe levels of low transmission. In this study, serological and parasitological methods were used to measure transmission levels of Plasmodium falciparum and Plasmodium vivax during an elimination programme (2012) in Chabahar District, Sistan and Baluchistan Province, south-eastern Iran.
  
  
  
  Participants were randomly selected from 64 different geographical clusters in Chabahar city and surrounding villages. Antibody responses to P. falciparum and P. vivax blood-stage antigens were assessed by ELISA, while microscopy and molecular testing were used to determine parasite carriage by species. Age-adjusted antibody responses were analysed using a reversible catalytic model to calculate seroconversion rates (SCR).
  
  
  
  There was no evidence of recent transmission in the study areas, indicated by an absence of parasite infections in all ages and low or absent serological responses to either species in young children. The best model for age P. falciparum seroconversion was one with a change in exposure 21 years before sampling was done in Chabahar city (P = 0.018) and 4 years in the villages (P = 0.039). There was a higher level of recent P. vivax transmission compared to P. falciparum, based on the SCRs, in both the city and village settings.
  
  
  
  Serological analysis identified a decline in P. falciparum transmission in the urban areas of Chabahar, consistent with a previously described decrease in malaria in the early 1990s, demonstrating the utility of this approach to reconstruct exposure history. At present, it remains unclear whether the P. vivax antibody responses reflect active transmission due to new infections or relapse infections. The absence of parasitological and serological evidence of recent malaria transmission in Chabahar District is viable evidence for certification of elimination.
authors.affiliation: Malaria and Vector Research Group (MVRG), Biotechnology Research Center (BCR), Pasteur Institute, P.O. Box: 1316943551, Tehran, Iran. zakeris@yahoo.com.
authors.forename: Sedigheh
authors.initials: S
authors.lastname: Zakeri
authors.affiliation: Department of Immunology and Infection, London School of Hygiene & Tropical Medicine, London, UK.
authors.forename: Lotus Leonie
authors.initials: LL
authors.lastname: van den Hoogen
authors.affiliation: Malaria and Vector Research Group (MVRG), Biotechnology Research Center (BCR), Pasteur Institute, P.O. Box: 1316943551, Tehran, Iran.
authors.forename: Akram Abouie
authors.initials: AA
authors.lastname: Mehrizi
authors.affiliation: Malaria and Vector Research Group (MVRG), Biotechnology Research Center (BCR), Pasteur Institute, P.O. Box: 1316943551, Tehran, Iran.
authors.forename: Fatemh
authors.initials: F
authors.lastname: Karimi
authors.affiliation: National Programme Manager for Malaria Control, Ministry of Health and Medical Education, Tehran, Iran.|School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Ahmad
authors.initials: A
authors.lastname: Raeisi
authors.affiliation: Department of Immunology and Infection, London School of Hygiene & Tropical Medicine, London, UK. Chris.Drakeley@lshtm.ac.uk.
authors.forename: Chris
authors.initials: C
authors.lastname: Drakeley
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000913:Antibodies, Protozoan / Q000097:blood*; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D016054:DNA, Protozoan / Q000032:analysis / Q000235:genetics; D060740:Disease Eradication; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D007492:Iran / Q000453:epidemiology; D016778:Malaria, Falciparum / Q000453:epidemiology* / Q000276:immunology / Q000469:parasitology; D016780:Malaria, Vivax / Q000453:epidemiology* / Q000276:immunology / Q000469:parasitology; D008297:Male; D008853:Microscopy; D008875:Middle Aged; D010963:Plasmodium falciparum / Q000276:immunology* / Q000302:isolation & purification; D010966:Plasmodium vivax / Q000276:immunology* / Q000302:isolation & purification; D016133:Polymerase Chain Reaction; D016036:Seroepidemiologic Studies; D014505:Urban Population; D055815:Young Adult
chemical_list: D000913:Antibodies, Protozoan; D016054:DNA, Protozoan