title: Incidence rate and risk factors for giardiasis and strongyloidiasis in returning UK travellers.
abstract: BACKGROUND
  Few studies have investigated incidence rate and risk factors for giardiasis and strongyloidiasis in returning UK travellers. The clinical presentations of these two diseases are often similar and difficult to distinguish. This study was conducted to investigate the incidence rate and the risk factors for symptomatic giardiasis and strongyloidiasis in returned tropical travellers.
  
  
  METHODS
  We retrospectively analysed 3306 consecutive attendances presenting to the emergency clinic at the Hospital for Tropical Diseases in London, the UK from September 2008 to May 2010. Odds ratios between the diagnoses and patient variables were analysed by logistic regression.
  
  
  RESULTS
  Giardiasis was diagnosed in 92/3306 cases (2.8%, proportionate morbidity), and the incidence rate per 1000 person-months was 12.5. Multivariate analysis with logistic regression revealed that Caucasian ethnicity (adjusted odds ratio (aOR): 2.37, 95% confidence interval (CI): 1.12-5.03, P value = 0.025), travel length ≥32 days (aOR: 2.63, 95%CI: 1.43-4.83, P = 0.002), travelling to South or South East Asia (aOR: 4.90, 95%CI: 2.03-11.8, P < 0.001, aOR: 3.36, 95%CI: 1.43-7.93, P = 0.006), afebrile presentation (aOR: 2.14, 95%CI: 1.14-4.03, P = 0.018), and presenting with gastro-intestinal symptoms (aOR: 14.6, 95%CI: 6.08-35.0, P < 0.001) were all associated with giardiasis. In contrast, strongyloidiasis was found only in 0.94% (proportionate morbidity) of the cases (31/3306), and the incidence rate per 1000 person-months was 3.1. Multivariate analysis revealed that male sex (aOR: 3.05, 95%CI: 1.36-6.85, P = 0.007), and non-Caucasian ethnicity (aOR: 2.69, 95%CI: 1.32-5.49, P = 0.007) were associated with strongyloidiasis.
  
  
  CONCLUSIONS
  The incidence rate and risk factors for both infectious diseases were identified. The results of this study might guide clinicians to make more accurate and timely diagnoses in returned tropical travellers.
authors.affiliation: Faculty of Infectious and Tropical Diseases, Department of Clinical Research, London School of Hygiene & Tropical Medicine, Keppel Street, London WC1E 7HT, UK.
authors.forename: Kensuke
authors.initials: K
authors.lastname: Takaoka
authors.affiliation: Faculty of Infectious and Tropical Diseases, Department of Clinical Research, London School of Hygiene & Tropical Medicine, Keppel Street, London WC1E 7HT, UK.
authors.forename: Yannis
authors.initials: Y
authors.lastname: Gourtsoyannis
authors.affiliation: Faculty of Infectious and Tropical Diseases, Department of Clinical Research, London School of Hygiene & Tropical Medicine, Keppel Street, London WC1E 7HT, UK.
authors.forename: John D
authors.initials: JD
authors.lastname: Hart
authors.affiliation: The Hospital for Tropical Diseases, London, UK.
authors.forename: Margaret
authors.initials: M
authors.lastname: Armstrong
authors.affiliation: The Hospital for Tropical Diseases, London, UK.
authors.forename: Amanda
authors.initials: A
authors.lastname: Daniel
authors.affiliation: The Hospital for Tropical Diseases, London, UK.
authors.forename: Emma
authors.initials: E
authors.lastname: Mewse
authors.affiliation: The Hospital for Tropical Diseases, London, UK.
authors.forename: Diana
authors.initials: D
authors.lastname: Phillips
authors.affiliation: Faculty of Infectious and Tropical Diseases, Department of Clinical Research, London School of Hygiene & Tropical Medicine, Keppel Street, London WC1E 7HT, UK.|The Hospital for Tropical Diseases, London, UK.
authors.forename: Robin L
authors.initials: RL
authors.lastname: Bailey
mesh_terms: D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D003141:Communicable Diseases / Q000175:diagnosis / Q000188:drug therapy / Q000453:epidemiology*; D005260:Female; D005873:Giardiasis / Q000175:diagnosis / Q000188:drug therapy / Q000453:epidemiology*; D006801:Humans; D015994:Incidence; D016015:Logistic Models; D008297:Male; D016017:Odds Ratio; D012189:Retrospective Studies; D012307:Risk Factors; D017678:Sex Distribution; D013322:Strongyloidiasis / Q000175:diagnosis / Q000188:drug therapy / Q000453:epidemiology*; D014195:Travel / Q000706:statistics & numerical data*; D014330:Tropical Medicine; D006113:United Kingdom
chemical_list: D000900:Anti-Bacterial Agents
keywords: giardiasis; incidence; multivariate analysis; risk factor; strongyloidiasis; travel medicine