pezhman alavinejad research center for infectious diseases of digestive system, ahvaz jundishapur university of medical sciences, ahvaz, ir iran; department of gastroenterology, ahvaz jundishapur university of medical sciences, ahvaz, ir iran; department of gastroenterology, ahvaz jundishapur university of medical sciences, ahvaz, ir iran. tel: +98-9161115880 seyed jalal hashemi research center for infectious diseases of digestive system, ahvaz jundishapur university of medical sciences, ahvaz, ir iran; department of gastroenterology, ahvaz jundishapur university of medical sciences, ahvaz, ir iran eskandar hajiani research center for infectious diseases of digestive system, ahvaz jundishapur university of medical sciences, ahvaz, ir iran; department of gastroenterology, ahvaz jundishapur university of medical sciences, ahvaz, ir iran atefe roomi research center for infectious diseases of digestive system, ahvaz jundishapur university of medical sciences, ahvaz, ir iran arman shahriari research center for infectious diseases of digestive system, ahvaz jundishapur university of medical sciences, ahvaz, ir iran elham karimi moghaddam ahvaz jundishapur university of medical sciences, ahvaz, ir iran