High prevalence of TT virus infection in healthy children and adults and in patients with liver disease in Taiwan

A newly identified DNA virus, named TT virus (TTV), was found to be related to transfusion-associated hepatitis. We conducted the following experiment s to evaluate its pathogenic role in liver disease and potential modes of t ransmission. We used PCR to detect TTV DNA in serum. The rates of TTV virem ia in 13 patients with idiopathic acute hepatitis, 14 patients with idiopat hic fulminant hepatitis, 22 patients with chronic hepatitis, and 19 patient s with cirrhosis of the liver were 46, 64, 55, and 63%, respectively, and w ere not significantly different from those in 50 healthy control subjects ( 53%), PCR products derived from seven patients with liver disease and three healthy controls were cloned and then subjected to phylogenetic analyses, which failed to link a virulent strain of TTV to severe liver disease. TTV infection was further assessed in an additional 148 subjects with normal li ver biochemical tests, including 30 newborns (sera collected from the umbil ical cord), 23 infants, 16 preschool children, 21 individuals of an age pri or to that of sexual experience (aged 6 to 15 years), 15 young adults (aged under 30 years), and 43 individuals older than 30 years. The rates of TTV viremia were 0, 17, 25, 33, 47, and 54%, respectively. These findings sugge st that TTV is transmitted mainly via nonparenteral daily contact and frequ ently occurs very early in life and that TTV infection does not have a sign ificant effect on liver disease.