Investigating giardiasis and long term complications

Bergen Giardia Research Group

Bergen Giardia Research Group (BGRG) is a network of scientists and physicians who cooperate in planning and implementing research projects to evaluate the long term sequelae after the Giardia epidemic and to understanding the mechanisms behind these. Some treatment trials have also been conducted.

We hope this research will lead to treatment alternatives for these conditions.



Publication list (updated March 2017):


1. Nygard K, Schimmer B, Sobstad O, Walde A, Tveit I, Langeland N, Hausken T, Aavitsland P. A large community outbreak of waterborne giardiasis-delayed detection in a non-endemic urban area. BMC Public Health. 2006 May 25;6:141.


2. Robertson LJ, Hermansen L, Gjerde BK, Strand E, Alvsvåg JO, Langeland N. Application of genotyping during an extensive outbreak of waterborne giardiasis in Bergen, Norway, during autumn and winter 2004.  Appl.Environ.Microbiol. 2006; 72:2212-7.


3. Robertson LJ, Forberg T, Hermansen L, Gjerde BK, Alvsvåg JO, Langeland N.  Cryptosporidium parvum infections in Bergen, Norway, during an extensive outbreak of waterborne giardiasis in autumn and winter 2004.  App Environ Microbiol. 2006;72(3):2218-20


4. Robertson LJ, Forberg T, Hermansen L, Gjerde BK and Langeland N. Molecular characterisation of Giardia isolates from clinical infection following a waterborne outbreakJ Infect. 2007 Jul;55(1):79-88.


5. Robertson LJ, Forberg T, Hermansen L, Gjerde B, Langeland N. Demographics of Giardia infections in Bergen, Norway, subsequent to a waterborne outbreak.  Scand J Infect Dis. 2007 Jul 31;:1-4


6. Wensaas KA, Langeland N, Rørtveit G. Uncovering the giardiasis-outbreak in Bergen 2004. Tidsskr Nor Laegeforen. 2007 Sep 6;127(17):2222-5


7. Hanevik K, Hausken T, Morken MH, Strand EA, Mørch K, Coll P, Helgeland L, Langeland N.  Persisting symptoms and duodenal inflammation related to Giardia duodenalis infections. J Infect. 2007 Dec;55(6):524-30.


8. Dizdar V, Gilja OH, Hausken T. Increased visceral sensitivity in Giardia-induced postinfectious irritable bowel syndrome and functional dyspepsia. Effect of the 5HT3-antagonist ondansetron. Neurogastroenterol Motil. 2007 Dec;19(12):977-82


9. Hanevik K, Mørch K, Eide GE, Langeland N, Hausken T. Effects of albendazole/metronidazole or tetracycline/folate treatments on persisting symptoms after Giardia infection: a randomised open clinical trial.  Scand J Infect Dis. 2008;40(6-7):517-22


10. Mørch K, Hanevik K, Robertson LJ, Strand EA, Langeland N. Treatment-ladder and genetic characterisation of parasites in refractory giardiasis after an outbreak in Norway. J Infect. 2008 Apr;56(4):268-73.


11. Robertson LJ, Forberg T, Gjerde B (2008). Giardia cysts in sewage influent in Bergen, Norway over one year after an extensive outbreak of giardiasis. J. Appl. Microbiol. 104: 1147-1152.


12. Strand, E.A., Robertson, L.J., Alvsåg, J.O. et al.  (2008). Sensitivity of a Giardia antigen test in persistent giardiasis following an extensive outbreak. Clin Microbiol Infect. 2008 Nov;14(11):1069-71.


13. Wensaas KA, Langeland N, Rortveit G. Prevalence of recurring symptoms after infection with Giardia lamblia in a non-endemic area. Scand J Prim Health Care. 2008 Dec 12:1-6.


14. Mørch K, Hanevik K, RortveitG, Wensaas KA, Langeland N. High rate of fatigue and abdominal symptoms 2 years after an outbreak of giardiasis. Trans R Soc Trop Med Hyg. 2009 May;103(5):530-2.


15. Hanevik K, Dizdar V, Langeland N, Hausken T. Development of functional gastrointestinal disorders after Giardia lamblia infection. BMC Gastroenterology 2009, 9:27 doi:10.1186/1471-230X-9-27


16. Morch K, Hanevik K, Rortveit G, Wensaas KA, Eide GE, Hausken T, Langeland N. Severity of Giardia infection associated with post-infectious fatigue and abdominal symptoms two years after. BMC Infect Dis. 2009, 9:206. doi:10-1186/1471-2334-9-206


17. Robertson LJ, Hanevik K, Escobedo AA, Mørch K, Langeland N. Giardiasis—why do the symptoms sometimes never stop. Trends Parasitol. 2010  Jan; 26(2):75-82 doi:10.1016/


18. Dizdar V, Spiller R, Singh G, Hanevik K, Gilja OH, El-Salhy M, Hausken T. Relative importance of abnormalities of CCK (cholecystokinin) and 5-HT(serotonin) in Giardia-induced post-infectious irritable bowel syndrome and functional dyspepsia. Aliment Pharmacol Ther. 2010 Feb 2.


19. Wensaas KA, Langeland N, Rortveit G. Post-infectious gastrointestinal symptoms after acute giardiasis. A 1-year follow-up in general practice. Fam Pract. 2010 Jun;27(3):255-9. 2010 Mar 22.


20. Mellingen KM, Midtun A, Hanevik K, Eide GE, Søbstad Ø, Langeland N. Post epidemic giardiasis and gastrointestinal symptoms among preschool children in Bergen, Norway. A cross-sectional study. BMC Public Health. 2010 Mar 26;10:163.


21. Escobedo AA, Almirall P, Robertson LJ, Franco RM, Hanevik K, Mørch K, Cimerman S. Giardiasis: the ever-present threat of a neglected disease. Infect Disord Drug Targets. 2010 Oct 1;10(5):329-48.


22. Hanevik K, Dizdar V, Langeland N, Eide GE, Hausken T. Tolerability and effect of mesalazine in postinfectious irritable bowel syndromeAliment Pharmacol Ther.2011 Jul;34(2):259-60.


23. Wensaas KA, Langeland N, Hanevik K, Mørch K, Eide GE, Rørtveit, G. Irritable bowel syndrome and chronic fatigue three years after acute giardiasis: historic cohort study. Gut 2012;61:214-19.


24. Hanevik K, Kristoffersen E, Svard S, Bruserud O, Ringqvist E, Sørnes S, Langeland N. Human Cellular Immune Response Against Giardia lamblia 5 Years After, Acute Giardiasis. J Infect Dis. 2011 Dec;204(11):1779-86.


25.Hunskar GS, Langeland N, Wensaas KA, Hanevik K, Eide GE, Mørch K, Rortveit G. The impact of atopic disease on the risk of post-infectious fatigue and irritable bowel syndrome 3 years after Giardia infection. A historic cohort study. Scand J Gastroenterol. 2012 Jul 2.


26. Hanevik K, Kristoffersen EK, Sørnes S, Mørch K, Næss H, Rivenes AC, Bødtker JE, Hausken T, Langeland N. Immunophenotyping in post-giardiasis functional gastrointestinal disease and chronic fatigue syndrome. BMC Infect Dis. 2012 Oct 14;12(1):258

27. Mørch K, Hanevik K, Rivenes AC, Bødtker JE, Næss H, Stubhaug B, Wensaas KA, Rortveit G, Eide GE, Hausken T, Langeland N. Chronic fatigue syndrome 5 years after giardiasis: differential diagnoses, characteristics and natural course. BMC Gastroenterol. 2013 Feb 12;13(1):28

28. Hanevik K, Wensaas KA, Rortveit G, Eide GE, Mørch K, Langeland N. Irritable bowel syndrome and chronic fatigue six years after Giardia infection: a controlled prospective cohort study. Clin Infect Dis. Advance access online August 12, 2014.

29. Hanevik K, Bakken R, Brattbakk HR, Saghaug CS, Langeland N. Whole genome sequencing of clinical isolates of Giardia lamblia. Clin Microbiol Infect. 2015 Feb;21(2):192.e1-3.

30. Persson R, Wensaas KA, Hanevik K, Eide GE, Langeland N, Rortveit G. The relationship between irritable bowel syndrome, functional dyspepsia, chronic fatigue and overactive bladder syndrome: a controlled study 6 years after acute gastrointestinal infection. BMC Gastroenterol. 2015 Jun 10;15:66.


31. Saghaug CS, Sørnes S, Peirasmaki D, Svärd S, Langeland N, Hanevik K. Human Memory CD4+ T Cell Immune Responses against Giardia lamblia. Clin Vaccine Immunol. 2015 Sep 16;23(1):11-8.


32. Robertson LJ, Tysnes KR, Hanevik K, Langeland N, Mørch K, Hausken T, Nygård K. Dogs as the source of Giardia in Bergen in 2004 – barking up the wrong tree? Tidsskr Nor Laegeforen. 2015 Oct 20;135(19):1718-20.


33. Litleskare S, Wensaas KA, Eide GE, Hanevik K, Kahrs GE, Langeland N, Rortveit G. Perceived food intolerance and irritable bowel syndrome in a population 3 years after a giardiasis-outbreak: a historical cohort study. BMC Gastroenterol. 2015 Nov 19;15:164.


34. Wensaas KA, Hanevik K, Hausken T, Eide GE, Langeland N, Mørch K, Rortveit G. Postinfectious and sporadic functional gastrointestinal disorders have different prevalences and rates of overlap: results from a controlled cohort study 3 years after acute giardiasis. Neurogastroenterol Motil. 2016 May 18.


35. Hunskar GS, Bjorvatn B, Wensaas KA, Hanevik K, Eide GE, Langeland N, Rortveit G. Excessive daytime sleepiness, sleep need and insomnia 3 years after Giardia infection: a cohort study. Sleep Health. 2016 June. Volume 2, Issue 2, Pages 154–158.


36. Hanevik K, Kristoffersen E, Mørch K, Rye KP, Sørnes S, Svärd S, Bruserud Ø,
Langeland N.
Giardia-specific cellular immune responses in post-giardiasis chronic fatigue syndrome. BMC Immunol. 2017 Jan 28;18(1):5.


BGRG & Publications

Webansvarlig: Kurt Hanevik

BGRG, Haukeland Universitetssykehus

Institutt for indremedisin

2.etg, sentralblokken

5021 Bergen, Norway

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