title: The role of parasitic infections in atopic diseases in rural schoolchildren.
abstract: BACKGROUND
  There is increasing evidence that the farming environment has a protective effect as regards allergic diseases. Exposure to animal parasites, particularly helminth infections, is common in the farming environment. However, the role of helminths in this environment is not well determined to date.
  
  
  METHODS
  This analysis focuses on 613 children 6-13 years of age from rural areas of Austria, Germany and Switzerland, who took part in the Allergy and Endotoxin (ALEX) study. Allergic diseases and farming characteristics were assessed by a standardized questionnaire and as a crude measure of possible exposure to helminths, IgG antibodies to Ascaris lumbricoides were measured.
  
  
  RESULTS
  Exposure to nematodes, as determined by the levels of antibody to A. lumbricoides, was more frequent among farmers' children than non-farmers' children (39.8%vs 31.1%, P = 0.03). This positive serology was found to be significantly associated with high total IgE levels [odds ratio (OR) = 3.05, 95% confidence interval (CI) = 1.81-5.12] and eosinophilia (OR = 2.84, 95% CI = 1.66-4.84). However, no association between anti-nematode serology and the prevalences of asthma, wheeze, hay fever or atopy was found. A weak association for atopy was observed after adjustment for total IgE.
  
  
  CONCLUSIONS
  Immunoglobulin G antibodies to A. lumbricoides, as a crude measure of possible exposure to helminths, did not indicate any protective effect against allergic diseases in this population. Although farmers' children had increased antibody levels reactive to helminth parasites indicating exposure, this did not explain the protective effect of farming against atopic diseases.
authors.affiliation: Children's Hospital, University of Munich, Munich, Germany.
authors.forename: B
authors.initials: B
authors.lastname: Karadag
authors.forename: M
authors.initials: M
authors.lastname: Ege
authors.forename: J E
authors.initials: JE
authors.lastname: Bradley
authors.forename: C
authors.initials: C
authors.lastname: Braun-Fahrländer
authors.forename: J
authors.initials: J
authors.lastname: Riedler
authors.forename: D
authors.initials: D
authors.lastname: Nowak
authors.forename: E
authors.initials: E
authors.lastname: von Mutius
mesh_terms: D000293:Adolescent; D000818:Animals; D000909:Antibodies, Helminth / Q000097:blood*; D001196:Ascariasis / Q000097:blood* / Q000453:epidemiology; D017164:Ascaris lumbricoides; D002648:Child; D004802:Eosinophilia / Q000097:blood / Q000453:epidemiology / Q000469:parasitology; D005260:Female; D006801:Humans; D006967:Hypersensitivity / Q000097:blood* / Q000453:epidemiology / Q000469:parasitology; D007073:Immunoglobulin E / Q000097:blood*; D007074:Immunoglobulin G / Q000097:blood*; D008297:Male; D012424:Rural Population
chemical_list: D000909:Antibodies, Helminth; D007074:Immunoglobulin G; D007073:Immunoglobulin E