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Bergen Giardiasis Cohort
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Design notes & limitations. Controlled cohort with a matched unexposed comparator and unusually long follow-up (3, 6, and 10 years), demonstrating persistence of post-infectious IBS and chronic fatigue after a protozoan (non-viral) infection.
Identity & trigger
- Cohort id
bergen-giardiasis-2004- Aliases
- Bergen Giardia outbreak cohort
- Outbreak / event
- Bergen giardiasis outbreak 2004 (Norway)
- Pathogen
- Giardia duodenalis (lamblia) (Protozoan)
- Exposure ascertainment
- Mixed
Design
- Design
- Retrospective cohort
- Denominator defined
- Yes
- Denominator method
- Individuals with laboratory-confirmed Giardia during the 2004 Bergen waterborne outbreak, compared with matched controls from the same population.
- Recruitment
- population registry
- Time zero
- Laboratory-confirmed acute giardiasis during the 2004 outbreak (quarter)
- Control group
- Unexposed (matched)
Size & attrition
- Enrolled
- 1252
- Analysed / enrolled
- 1252/1252 (100%)
- Max follow-up (months)
- 120
Biospecimens
- Specimens
- No
- Types
- none
- Acute-phase specimens
- No
- Biobank
- N/A
- External access
- Unknown
Observations (2)
Symptoms
39.4% Proportion
- Measure
- Irritable bowel syndrome (post-infectious) sym:irritable-bowel-syndrome
- As worded
- “irritable bowel syndrome 6 years after giardiasis”
- Population
- whole cohort · denominator Unclear · N=measured, not reported
- Timing
- 72 mo (24 mo+) · ref Not reported
- Method
- Unclear · Rome criteria for irritable bowel syndrome
- Comparator
- no comparator
- Comparability signature
- b1c0829e61 — measure sym:irritable-bowel-syndrome · Unclear · ref Not reported · denom Unclear · 24 mo+ · Proportion
- Provenance
- Results/Abstract (IBS 39.4% in exposed, significantly elevated vs controls) · Manual · verified OSMF research-tracker (web-verified against source) on 2026-07-20
30.8% Proportion
- Measure
- Fatigue sym:fatigue
- As worded
- “chronic fatigue 6 years after giardiasis”
- Population
- whole cohort · denominator Unclear · N=measured, not reported
- Timing
- 72 mo (24 mo+) · ref Not reported
- Method
- Unclear · Chalder Fatigue Scale
- Comparator
- no comparator
- Comparability signature
- 4126b3eea7 — measure sym:fatigue · Unclear · ref Not reported · denom Unclear · 24 mo+ · Proportion
- Provenance
- Results/Abstract (chronic fatigue 30.8% in exposed, significantly elevated vs controls) · Manual · verified OSMF research-tracker (web-verified against source) on 2026-07-20
Publications
- Hanevik K, Wensaas KA, Rortveit G, et al. (2014). Irritable bowel syndrome and chronic fatigue 6 years after giardia infection: a controlled prospective cohort study. Clinical Infectious Diseases. PMID 25115874 · DOI 10.1093/cid/ciu629 primary
Provenance & verification
- Registration
- n/r
- Funders
- Haukeland University Hospital / University of Bergen
- Related cohorts
- none
- Symptom-inventory scope
- Targeted panel
- Last verified
- 2026-07-20 — OSMF research-tracker (web-verified against source)