title: Hotspots of Malaria Transmission in the Peruvian Amazon: Rapid Assessment through a Parasitological and Serological Survey.
abstract: BACKGROUND
  With low and markedly seasonal malaria transmission, increasingly sensitive tools for better stratifying the risk of infection and targeting control interventions are needed. A cross-sectional survey to characterize the current malaria transmission patterns, identify hotspots, and detect recent changes using parasitological and serological measures was conducted in three sites of the Peruvian Amazon.
  
  
  METHODS
  After full census of the study population, 651 participants were interviewed, clinically examined and had a blood sample taken for the detection of malaria parasites (microscopy and PCR) and antibodies against P. vivax (PvMSP119, PvAMA1) and P. falciparum (PfGLURP, PfAMA1) antigens by ELISA. Risk factors for malaria infection (positive PCR) and malaria exposure (seropositivity) were assessed by multivariate survey logistic regression models. Age-specific seroprevalence was analyzed using a reversible catalytic conversion model based on maximum likelihood for generating seroconversion rates (SCR, λ). SaTScan was used to detect spatial clusters of serology-positive individuals within each site.
  
  
  RESULTS
  The overall parasite prevalence by PCR was low, i.e. 3.9% for P. vivax and 6.7% for P. falciparum, while the seroprevalence was substantially higher, 33.6% for P. vivax and 22.0% for P. falciparum, with major differences between study sites. Age and location (site) were significantly associated with P. vivax exposure; while location, age and outdoor occupation were associated with P. falciparum exposure. P. falciparum seroprevalence curves showed a stable transmission throughout time, while for P. vivax transmission was better described by a model with two SCRs. The spatial analysis identified well-defined clusters of P. falciparum seropositive individuals in two sites, while it detected only a very small cluster of P. vivax exposure.
  
  
  CONCLUSIONS
  The use of a single parasitological and serological malaria survey has proven to be an efficient and accurate method to characterize the species specific heterogeneity in malaria transmission at micro-geographical level as well as to identify recent changes in transmission.
authors.affiliation: Instituto de Medicina Tropical Alexander von Humboldt, Universidad Peruana Cayetano Heredia, Lima 31, Perú; Research Institute of Health and Society (IRSS), Université catholique de Louvain, Brussels 1200, Belgium; Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp 2000, Belgium.
authors.forename: Angel
authors.initials: A
authors.lastname: Rosas-Aguirre
authors.affiliation: Research Institute of Health and Society (IRSS), Université catholique de Louvain, Brussels 1200, Belgium.
authors.forename: Niko
authors.initials: N
authors.lastname: Speybroeck
authors.affiliation: Instituto de Medicina Tropical Alexander von Humboldt, Universidad Peruana Cayetano Heredia, Lima 31, Perú
authors.forename: Alejandro
authors.initials: A
authors.lastname: Llanos-Cuentas
authors.affiliation: Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp 2000, Belgium.
authors.forename: Anna
authors.initials: A
authors.lastname: Rosanas-Urgell
authors.affiliation: Instituto de Medicina Tropical Alexander von Humboldt, Universidad Peruana Cayetano Heredia, Lima 31, Perú
authors.forename: Gabriel
authors.initials: G
authors.lastname: Carrasco-Escobar
authors.affiliation: Región de Salud Loreto, Iquitos, Loreto 160, Peru.
authors.forename: Hugo
authors.initials: H
authors.lastname: Rodriguez
authors.affiliation: Instituto de Medicina Tropical Alexander von Humboldt, Universidad Peruana Cayetano Heredia, Lima 31, Perú; Departamento de Ciencias Celulares y Moleculares, Facultad de Ciencias y Filosofia, Universidad Peruana Cayetano Heredia, Lima 31, Peru.
authors.forename: Dionicia
authors.initials: D
authors.lastname: Gamboa
authors.affiliation: Instituto de Medicina Tropical Alexander von Humboldt, Universidad Peruana Cayetano Heredia, Lima 31, Perú
authors.forename: Juan
authors.initials: J
authors.lastname: Contreras-Mancilla
authors.affiliation: Región de Salud Loreto, Iquitos, Loreto 160, Peru.
authors.forename: Freddy
authors.initials: F
authors.lastname: Alava
authors.affiliation: Departamento de Análises Clínicas e Toxicológicas, Faculdade de Ciências Farmacêuticas, Universidade de São Paulo, São Paulo 05508-900, Brazil.
authors.forename: Irene S
authors.initials: IS
authors.lastname: Soares
authors.affiliation: Department of Parasitology, Biomedical Primate Research Centre, 2280 GH Rijswijk, The Netherlands.
authors.forename: Edmond
authors.initials: E
authors.lastname: Remarque
authors.affiliation: Disease Control and Elimination, Medical Research Council Unit, Fajara 220, The Gambia; London School of Hygiene & Tropical Medicine, London WC1E 7HT, United Kingdom.
authors.forename: Umberto
authors.initials: U
authors.lastname: D Alessandro
authors.affiliation: Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp 2000, Belgium.
authors.forename: Annette
authors.initials: A
authors.lastname: Erhart
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D005163:Factor Analysis, Statistical; D005843:Geography; D006801:Humans; D015994:Incidence; D016778:Malaria, Falciparum / Q000097:blood* / Q000453:epidemiology / Q000469:parasitology / Q000635:transmission*; D016780:Malaria, Vivax / Q000097:blood* / Q000453:epidemiology / Q000469:parasitology / Q000635:transmission*; D015999:Multivariate Analysis; D010568:Peru / Q000453:epidemiology; D010963:Plasmodium falciparum; D010966:Plasmodium vivax; D015995:Prevalence; D012307:Risk Factors; D016036:Seroepidemiologic Studies; D013045:Species Specificity; D055815:Young Adult