1. Department of Infectology , Rīga Stradiņš University , 16 Dzirciema Str ., Rīga , Latvia
2. Faculty of Medicine , University of Latvia , 19 Raiņa Blvd ., Rīga , Latvia
3. Department of Internal Diseases , Rīga Stradiņš University , 16 Dzirciema Str ., Rīga , Latvia
4. Rīga East University Hospital , 2 Hipokrāta Str ., Rīga , Latvia
5. Department of Gastroenterology and Hepatology , Radboud UMC, P.O. Box 9101, 6500 HB Nijmegen , The Netherlands