1. Universidade Federal de Minas Gerais; Department of Internal Medicine; School of Medicine Belo Horizonte Minas Gerais Brazil
2. Universidade Federal de Minas Gerais, University Hospital, Alfa Institute of Gastroenterology; Belo Horizonte Minas Gerais Brazil
3. Unit of Gastroenterology and Hepatology; Portuguese Hospital Salvador Bahia Brazil
4. Children Institute of University of Sao Paulo School of Medicine; Sao Paulo Brazil
5. Laboratory of Medical Investigation (LIM 06) of Institute of Tropical Medicine of University of Sao Paulo; Sao Paulo Brazil
6. Department of Gastroenterology of University of Sao Paulo School of Medicine; São Paulo Brazil