|dc.description.abstract||Background: A high rate of post-infectious fatigue and abdominal symptoms two years after a
waterborne outbreak of giardiasis in Bergen, Norway in 2004 has previously been reported. The
aim of this report was to identify risk factors associated with such manifestations.
Methods: All laboratory confirmed cases of giardiasis (n = 1262) during the outbreak in Bergen in
2004 received a postal questionnaire two years after. Degree of post-infectious abdominal
symptoms and fatigue, as well as previous abdominal problems, was recorded. In the statistical
analyses number of treatment courses, treatment refractory infection, delayed education and sick
leave were used as indices of protracted and severe Giardia infection. Age, gender, previous
abdominal problems and symptoms during infection were also analysed as possible risk factors.
Simple and multiple ordinal logistic regression models were used for the analyses.
Results: The response rate was 81% (1017/1262), 64% were women and median age was 31 years
(range 3-93), compared to 61% women and 30 years (range 2-93) among all 1262 cases. Factors in
multiple regression analysis significantly associated with abdominal symptoms two years after
infection were: More than one treatment course, treatment refractory infection, delayed
education, bloating and female gender. Abdominal problems prior to Giardia infection were not
associated with post-infectious abdominal symptoms. More than one treatment course, delayed
education, sick leave more than 2 weeks, and malaise at the time of infection, were significantly
associated with fatigue in the multiple regression analysis, as were increasing age and previous
Conclusion: Protracted and severe giardiasis seemed to be a risk factor for post-infectious fatigue
and abdominal symptoms two years after clearing the Giardia infection.||en