Age-specific prevalence and transmission of TT virus

TT virus (TTV) is an unenveloped, single-stranded DNA virus that was discov ered recently in the sera of Japanese patients with posttransfusion hepatit is of unknown etiology. A high prevalence of TTV infection in blood donors of several countries, including Brazil, has been demonstrated. To study the variation in TTV prevalence between different age groups, sera from 223 in dividuals without liver disease, aged 0-80 years, were tested by the polyme rase chain reaction for the presence of TTV DNA. All subjects were inhabita nts of the city of Rio de Janeiro, Brazil. The prevalence increased continu ously with age (P < .001), from 17% among children under the age of 11 year s, to 57% in people older than 50 years. To assess vertical transmission, s era from 105 unselected, consecutive parturient women attending a public ma ternity hospital were paired with cord bloods and examined for the presence of TTV DNA. Thirty-seven (35%) mothers were found to be TTV infected. Seve n cord bloods were also positive, suggesting the possible transplacental tr ansmission of the virus. Furthermore, a direct correlation between TTV vire mia and presence of antibodies to the enterically transmissible hepatitis A virus (HAV) was observed in this group of women, with a relative risk of T TV infection of 5.09 (95% confidence interval 0.76-34.03) for women with an ti-HAV, compared with women without. This finding suggested that the fecal- oral route might be an important route of TTV transmission. (C) 1999 Wiley- Liss, Inc.