Emerging Infectious Diseases (Feb 2003)

Risk Factors for Sporadic Giardiasis: a Case-Control Study in Southwestern England

  • James M. Stuart,
  • Hilary J. Orr,
  • Fiona G Warburton,
  • Sugarthinny Jeyakanth,
  • Carolyn Pugh,
  • Ian Morris,
  • Joyshri Sarangi,
  • Gordon Nichols

DOI
https://doi.org/10.3201/eid0902.010488
Journal volume & issue
Vol. 9, no. 2
pp. 229 – 233

Abstract

Read online

To investigate risk factors for sporadic infection with Giardia lamblia acquired in the United Kingdom, we conducted a matched case-control study in southwest England in 1998 and 1999. Response rates to a postal questionnaire were 84% (232/276) for cases and 69% (574/828) for controls. In multivariable analysis, swallowing water while swimming (p<0.0001, odds ratio [OR] 6.2, 95% confidence intervals [CI] 2.3 to 16.6), recreational fresh water contact (p=0.001, OR 5.5, 95% CI 1.9 to 15.9), drinking treated tap water (p<0.0001, OR 1.3, 95% CI 1.1 to 1.5 for each additional glass per day), and eating lettuce (p=0.01, OR 2.2, 95% CI 1.2 to 4.3) had positive and independent associations with infection. Although case-control studies are prone to bias and the risk of Giardia infection is minimized by water treatment processes, the possibility that treated tap water is a source of sporadic giardiasis warrants further investigation.

Keywords