In a 4-year follow-up study, patients with acute sporadic non-A, non-B (NANB) hepatitis were evaluated to determine the etiology and natural history of the disease. Acute hepatitis C virus (HCV) was detected in 13 of 43 (30%) of patients, anti-hepatitis E virus (HEV) IgG in 5 (12%), and 25 (58%) were considered non-A-E. The HCV RNA was detected in all HCV patients but none of the non-A-E cases. The initial clinical and biochemical presentation of the HCV and non-A-E cases was quite similar, although 2 of the non-A-E patients had severe disease. The 5 patients who were found to be anti-HEV IgG-reactive recovered within 6 months of follow-up. Of the 13 HCV cases, alanine transaminase (ALT) levels returned to normal in 7 (53.8%), while 6 (46.2%) continued to show abnormal ALT after 6 months of follow-up. However, 9 (69.2%) of them remained HCV-RNApositive, denoting virological/biochemical dissociation. Longterm follow-up showed a reappearance of HCV RNA in 2 of the 4 patients who were in virological remission performing 84% of chronicity rate. Acute non-A-E hepatitis patients were less likely to evolve toward chronicity, as compared with acute HCV cases (16% vs. 84%; P ؍ .0001). Only 4 (16%) of the non-A-E patients were hepatitis G virus (HGV)-RNA-positive. Concerning risk factors for acquiring parenterally transmitted viruses, tattooing was the only one that could be associated with HCV transmission (P ؍ .002). No risk factors could be identified for putative non-A-E virus transmission. Liver biopsies performed for chronic HCV patients showed a variable degree of inflammation, while the non-A-E patients presented less severe histological disease. (HEPATOLOGY 1999;30:289-293.)
Despite the recent identification of hepatitis virus types C (HCV) and E (HEV), a significant number of acute viral hepatitis cases remain of unknown etiology and, following the existing nomenclature, are classified as hepatitis non-A-E. 1,2 The spectrum of clinical manifestations of non-A-E hepatitis appears to be generally relatively benign, although fulminant forms have been described. 3 While HCV is present in the majority of the non-A, non-B (NANB) hepatitis cases seen in Europe and the United States, HEV is more frequently found in Asia and Africa. 4,5 In Brazil, HEV has rarely been found in cases of acute viral hepatitis (R. Parana ´, unpublished data, October, 1993) or in seroepidemiological studies, suggesting significant epidemiological variations when compared with endemic areas. 6 Hepatitis C is largely predominant in subjects from groups at high risk for parenteral transmission. However, for over 30% of people who have contracted this disease, the transmission route is unknown. These cases represent what is now referred to as the sporadic form of the disease. 7,8 The recently discovered hepatitis G virus (HGV) has been shown to account for only a small percentage of acute non-A-E hepatitis cases. 9 The aim of this study was to investigate the principal etiologies and risk factors for acute viral hepatitis cases treated at a referral center for liver disease in northeastern Brazil, and the clinical and epidemiological features of the group of unknown-etiology hepatitis cases, focusing on subsequent clinical evolution.