title: The role of local disease perception in the selection of medicinal plants: A study of the structure of local medical systems.
abstract: BACKGROUND
  In this study, we investigated the role of local perceptions of diseases in the selection of medicinal plants. For this purpose, we consulted local experts from two communities located in the semiarid region of northeastern Brazil.
  
  
  METHODS
  After selecting the experts, we used semi-structured interviews to assess the symptoms of each disease studied, the perception of variations in each of these diseases, and the plants used for their treatment. We then conducted a participatory workshop in which the experts engaged in free grouping of the diseases mentioned in the first step.
  
  
  RESULTS
  We observed that the therapeutic targets (diseases) showed a lower similarity of medicinal plants than the perceived variants of these targets. We found that plant selection was associated with the perception of symptoms: the greater the similarity between two diseases based on the perceived symptoms, the greater the similarity between these diseases based on the medicinal plants. Furthermore, we observed a greater similarity between plants used to treat diseases perceived as related to each other.
  
  
  CONCLUSIONS
  Local perceptions of the association between diseases and between diseases and symptoms can influence plant selection such that the similarity of the medicinal plants chosen is higher for the diseases perceived as related and as having common symptoms. These results indicate the presence of mechanisms by which local perceptions of diseases affect the structures of local medical systems.
authors.affiliation: Laboratory of Ecology and Evolution of Social-Ecological Systems (LEA), Department of Biology, Federal Rural University of Pernambuco, Av. Dom Manoel de Medeiros, s/n, Dois Irmãos, 52171-900 Recife, PE, Brazil. Electronic address: kba.bio@hotmail.com.
authors.forename: Washington Soares
authors.initials: WS
authors.lastname: Ferreira Júnior
authors.affiliation: Bioassays Laboratory for Pharmaceutical Research, Federal University of Pernambuco, Department of Antibiotics, Cidade Universitária, 52171-900 Recife, PE, Brazil.
authors.forename: Teresinha Gonçalves
authors.initials: TG
authors.lastname: da Silva
authors.affiliation: Laboratory of Molecular Pharmacology and Chemistry, Department of Chemistry and Biology, Regional University of Cariri, 63105-000 Crato, CE, Brazil.
authors.forename: Irwin Rose
authors.initials: IR
authors.lastname: Alencar Menezes
authors.affiliation: Laboratory of Ecology and Evolution of Social-Ecological Systems (LEA), Department of Biology, Federal Rural University of Pernambuco, Av. Dom Manoel de Medeiros, s/n, Dois Irmãos, 52171-900 Recife, PE, Brazil. Electronic address: upa677@hotmail.com.
authors.forename: Ulysses Paulino
authors.initials: UP
authors.lastname: Albuquerque
mesh_terms: D001938:Brazil; D004194:Disease; D019448:Ethnobotany / Q000379:methods; D007722:Health Knowledge, Attitudes, Practice; D006801:Humans; D008519:Medicine, Traditional / Q000379:methods; D010465:Perception; D008517:Phytotherapy / Q000379:methods; D028321:Plant Preparations / Q000627:therapeutic use*; D010946:Plants, Medicinal / Q000737:chemistry*
chemical_list: D028321:Plant Preparations
keywords: Disease variations; Ethnomedicine; Evolutionary ethnobiology; Perception of symptoms; Traditional medicine