title: Poor sanitation and helminth infection protect against skin sensitization in Vietnamese children: A cross-sectional study.
abstract: BACKGROUND
  Geohelminth infection and poor hygiene may be protective against allergic sensitization.
  
  
  OBJECTIVE
  To determine whether current helminth infection is associated with a reduced prevalence of allergen skin test sensitization in a Southeast Asian population of children with a high prevalence of hookworm infection.
  
  
  METHODS
  A total of 1742 Vietnamese schoolchildren were invited to take part in a cross-sectional survey. Allergen skin sensitization to house dust mites (Dermatophagoides pteronyssinus and Dermatophagoides farinae) and American cockroach (Periplaneta americana) were measured and stool samples for qualitative and quantitative geohelminth estimation collected.
  
  
  RESULTS
  A total of 1601 children age 6 to 18 participated. Sensitization to dust mites was present in 14.4% and to cockroach in 27.6% of children. In a mutually adjusted model, the risk of sensitization to dust mites was reduced in those with higher hookworm burden (adjusted odds ratio [OR] for 350+ vs no eggs per gram, 0.61; 95% CI, 0.39-0.96) and with Ascaris infection (adjusted OR, 0.28; 0.10-0.78), and increased in those using flush toilets (adjusted OR for flush toilet vs none/bush/pit, 2.51; 1.00-6.28). In contrast, sensitization to cockroach was not independently related to geohelminth infection but was increased in those regularly drinking piped or well water rather than from a stream (adjusted OR, 1.33; 1.02-1.75).
  
  
  CONCLUSIONS
  Geohelminth infection, sanitation, and water supply influence the risk of allergic sensitization in Vietnamese children. This is consistent with a protective effect against allergy by geohelminth or other gastrointestinal infection.
  
  
  CONCLUSIONS
  If the inverse relationship between geohelminth infection, poor sanitation, and allergic sensitization proves to be causal, drugs derived from parasite products may help to alleviate clinical allergic disease.
authors.affiliation: Oxford University Clinical Research Unit, Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam. flohr@dng.vnn.vn
authors.forename: Carsten
authors.initials: C
authors.lastname: Flohr
authors.forename: Luc Nguyen
authors.initials: LN
authors.lastname: Tuyen
authors.forename: Sarah
authors.initials: S
authors.lastname: Lewis
authors.forename: Rupert
authors.initials: R
authors.lastname: Quinnell
authors.forename: Truong Tan
authors.initials: TT
authors.lastname: Minh
authors.forename: Ho Thanh
authors.initials: HT
authors.lastname: Liem
authors.forename: Jim
authors.initials: J
authors.lastname: Campbell
authors.forename: David
authors.initials: D
authors.lastname: Pritchard
authors.forename: Tran Tinh
authors.initials: TT
authors.lastname: Hien
authors.forename: Jeremy
authors.initials: J
authors.lastname: Farrar
authors.forename: Hywel
authors.initials: H
authors.lastname: Williams
authors.forename: John
authors.initials: J
authors.lastname: Britton
mesh_terms: D000293:Adolescent; D000485:Allergens / Q000009:adverse effects; D000818:Animals; D001196:Ascariasis; D002648:Child; D003058:Cockroaches / Q000276:immunology; D003430:Cross-Sectional Studies; D017449:Dermatitis, Allergic Contact / Q000453:epidemiology* / Q000517:prevention & control; D004391:Dust / Q000276:immunology; D005260:Female; D006373:Helminthiasis / Q000453:epidemiology*; D006801:Humans; D007114:Immunization; D008297:Male; D008925:Mites / Q000276:immunology; D015995:Prevalence; D012307:Risk Factors; D012424:Rural Population; D012499:Sanitation; D014744:Vietnam / Q000453:epidemiology
chemical_list: D000485:Allergens; D004391:Dust