By Suzanne D. Vernon, PhD
The CFIDS Association of America
In 2004, the medical municipalities in Bergen, Norway, were alerted to an increased number of laboratory-confirmed cases of giardiasis, an acute gastrointestinal illness caused by infection of the digestive tract with a protozoa called Giardia lamblia. Prior to this suspected outbreak, only one to two domestic cases of giardiasis were reported each year in Norway. Ultimately, 1,300 laboratory-confirmed cases were reported, with many more suspected cases identified through a Norwegian Prescription Database, possibly linked to the outbreak. People receiving water from the water reservoir serving central Bergen were at highest risk of infection. An earlier investigation of the people affected by the outbreak showed that daily intake of five glasses of tap water was associated with a higher risk of giardiasis during the outbreak . Leaking sewage pipes and insufficient water treatment were responsible for the water contamination and were likely the cause of the outbreak of illness that occurred between October 2004 and December 2005.
Several studies have been published on the chronic clinical consequences linked to the Bergen outbreak. Persistent gastrointestinal symptoms were common one year after the contamination. Two years after the outbreak, fatigue and abdominal symptoms were predominant in people with laboratory-confirmed Giardia-positive stool samples. The three-year follow-up study published on Sept. 12, 2011, in the journal Gut finds that people infected with Giardia during the outbreak have significantly increased rates of irritable bowel syndrome (IBS) and chronic fatigue . (See a brief summary and links to medical outlets’ coverage of the story from earlier today posted at http://www.research1st.com/2011/09/13/giardia-link/)
For the three-year follow-up, the authors sent questionnaires to 1,252 “exposed” people that had confirmed Giardia-positive stool samples at the time of the outbreak. They sent the same questionnaire to twice as many people not exposed to Giardia; this group served as the control population, an important enhancement of the follow-up that was not part of earlier studies of this group. The Rome III Diagnostic Questionnaire was used to evaluate irritable bowel syndrome (IBS) symptoms and the Fatigue Questionnaire was used to assess fatigue severity and duration. IBS and chronic fatigue were detected in 46 percent of the Giardia exposed group, compared to 14 percent of the unexposed control group for IBS and 12 percent for chronic fatigue. The prevalence of IBS was slightly higher for women in the exposed group; the rate of chronic fatigue was the same for women and men in the exposed group. The authors conclude that the risk of developing IBS and chronic fatigue as a long-term clinical consequence of infection with Giardia is high and more severe than previously expected. But is it?
Post-infection syndromes characterized by symptoms of fatigue, pain, poor sleep and cognitive disturbances have been described in the medical literature for the past 75 years and will likely continue as long as there are infectious disease outbreaks. Five years ago, a seminal paper by Hickie et al. published in the British Medical Journal showed that three different pathogens caused similar rates of persistent post-infection fatiguing illness . A recent paper by Dr. Harvey Moldofsky described chronic widespread musculoskeletal pain, fatigue, depression and disordered sleep in people infected with the SARS virus . Persistent joint pain and fatigue followed Chikungunya virus infection in India . IBS and hypertension persisted in people who developed gastroenteritis from drinking water contaminated with Escherichia coli O157:H7 and Campylobacter in Walkerton, Ontario .
Long-term post-infection clinical consequences are common, but are often poorly documented. The sooner the medical and scientific communities accept the reality that acute infection has chronic consequences – consequences that include diseases like CFS – the closer we will be to solving – and resolving – CFS.
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 Wensaas KA, Langeland N, Hanevik K, Morch K, Eide GE, Rortveit G. Irritable bowel syndrome and chronic fatigue three years after acute giardiasis: historic cohort study. Gut. Online ahead of press, Sept. 12, 2011. doi: 10/1136/gutjnl-2011-300220.
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 Marshall JK, Thabane M, Garg AX, Clark WF, Moayyedi P, Collins SM; Walkerton Health Study Investigators. Eight year prognosis of postinfectious irritable bowel syndrome following waterborne bacterial dysentery. Gut. 2010 May;59(5):605-11.