[Note: To read the full text of this article free, click HERE. Giardiasis is a parasitic infection of the intestine known virtually worldwide and caused by microscopic protozoa from feces of infected animals and humans – often via untreated water from streams/lakes, contaminated water supplies, or close contact, as in day care centers.]
Background: Giardia lamblia is a common cause of gastroenteritis worldwide, but there is limited knowledge about the long-term complications.
Objective: To estimate the relative risk of irritable bowel syndrome (IBS) and chronic fatigue 3 years after acute giardiasis.
Design: Controlled historic cohort study with 3 years’ follow-up. Data collected by mailed questionnaire.
Setting: Waterborne outbreak of giardiasis in the city of Bergen, Norway.
Participants: 817 patients exposed to Giardia lamblia infection verified by detection of cysts in stool samples and 1,128 matched controls.
Main outcome measures: IBS and chronic fatigue.
The prevalence of IBS in the exposed group was 46.1%, compared with 14.0% in the control group, and the adjusted RR=3.4 (95% CI 2.9 to 3.8). [A risk ratio of 1.0 would represent no difference in risk between the groups. An RR of 3.4 would indicate a 240% greater likelihood of IBS in the exposed group vs the controls.]
Chronic fatigue was reported by 46.1% of the exposed group and 12.0% of the controls, the adjusted RR was 4.0 (95% CI 3.5 to 4.5). [Exposed group likelihood of having chronic fatigue about 300% greater.]
IBS and chronic fatigue were associated and the RR for the exposed group of having a combination of the two outcomes was 6.8 (95% CI 5.3 to 8.5). [Exposed group likelihood of having IBS & chronic fatigue about 580% greater.]
The RR was also increased for having just one of the two syndromes, 1.8 for IBS (95% CI 1.4 to 2.3) and 2.2 for chronic fatigue (95% CI 1.7 to 2.8).
Infection with Giardia lamblia in a non-endemic area was associated with a high prevalence of IBS and chronic fatigue 3 years after acute illness, and the risk was significantly higher than in the control group.
This shows that the potential consequences of giardiasis are more serious than previously known. Further studies are needed, especially in areas where giardiasis is endemic.
Source: Gut, Sep 12, 2011. DOI:10.1136/gutjnl-2011-300220, by Wensaas KA, Langeland N, Hanevik K, Morch K, Eide GE, Rortveit G. Department of Public Health and Primary Healthcare, University of Bergen, Bergen, Norway. [Email: firstname.lastname@example.org]