Razieh Sadati - Department of Microbiology, Faculty of Science, Islamic Azad University of Tonekabon, Tonekabon, Iran.
Amin Barghi - Young Researchers Club, Lahijan branch, Islamic Azad University, Lahijan, Iran.
Mohammad Ali Harighi - Department of Microbiology, Faculty of Science, Islamic Azad University of Rasht, Rasht, Iran.

Background: Crohn s disease (CD) is an inflammatory disorder of the gastrointestinal tract, the cause of which remains unknown. Although Mycobacterium paratuberculosis has been identified in intestinal tissue from a proportion of patients with Crohn s disease, a convincing role for this agent in the aetiology of Crohn s disease has not been established. Likewise, extensive studies into bacterial and viral agents potentially associated with Crohn s disease have been inconclusive, although recent ultrastructural observations of viral particles have added a new impetus to the search. This review examines the evidence for an association between Crohn s disease and viral infection.Material and Methods: A search of online databases was performed and literature selection was carried out by reading titles, abstracts and full texts. Also publications bias was assessed.Results: Recent research has shown that SDWLHQWV ZLWK &URKQʼV GLVHDVH are at higher risk of hepatitis C (HCV) and B virus (HBV) infection, because of surgical or endoscopic procedures. However, the prevalence of HCV and HBV infection in CD is unknown. Some reports have claimed that persistent measles virus infection is involved in the aetiology or pathogenesis of CD. Using a variety of techniques, report that measles virus particles were detected in tissues from SDWLHQWV ZLWK &URKQʼV GLVHDVH. Moreover the results showed significant amounts of enteroviruses in the intestines of all of the children with Crohn s disease.Conclusion: A high HCV and HBV prevalence was expected in <50 years old because of a higher proportion of patients with CD undergoing surgery early in life. This issue may be relevant in relation to the wide use of immunomodulatory drugs in CD and for possible prevention and early diagnosis of hepatitis virus infection.

Crohn’s Disease, Viral infection