Morbidity of schistosomiasis in an endemic area of the Northeast of the State of Minas Gerais in Brazil: a clinical and sonographic study oleh MJ Martins, RA Pinto-Silva, JC Serufo, AAM Rayes, MPS Damasceno, MLV Martins, APS Santos, SC Drummond, MAS Bezerra, JR Lambertucci