目的了解新型肝炎病毒－ＴＴＶ的致病性和在健康人群和肝病患者中的流行情况．方法收集１８０份健康体检患者血清和１５６份不同类型肝病患者血清，采用ＰＣＲ方法检测ＴＴＶ的ＤＮＡ．同时检测ＨＡＶ，ＨＢＶ，ＨＣＶ，ＨＥＶ和ＨＧＶ感染标志，比较分析ＴＴＶ在健康人群和不同类型肝病患者中流行情况及其致病性．结果健康体检人群和肝病患者中，ＴＴＶＤＮＡ检出率分别为２２％和４５％，两组间无显著性差异（Ｐ＞００５）．体检人群中，ＡＬＴ正常和升高者的检出率分别为１７％和１４３％．急性肝炎，慢性肝炎和肝硬变者的检出率分别为４８％，４３％和４７％．１１例阳性患者中，３例ＡＬＴ正常，８例ＡＬＴ异常．在８例ＡＬＴ异常患者中，６例为ＨＢＶ现行感染，１例为ＨＣＶ现行感染，仅１例为ＮＡ－Ｇ肝炎患者．结论在中国健康体检人群和肝病患者中能检出低水平的ＴＴＶ现行感染．但似乎仅引起个别患者的转氨酶轻度升高．ＴＴＶ的致病性可能较弱或需要其他因素协同致病． Objective To understand the pathogenicity of the new hepatitis virus-TTV and its prevalence in healthy people and patients with liver disease. Methods Serum from 180 healthy people and 156 patients with different types of liver disease were collected. The DNA of TTV was detected by PCR. At the same time, the signs of HAV, HBV, HCV, HEV and HGV infection were detected, and the prevalence and pathogenicity of TTV in healthy people and different types of liver disease were analyzed. Results The positive rate of TTVDNA was 2. 2% and 45% respectively in healthy physical examination group and liver disease group, there was no significant difference between the two groups (P> 005). In the medical examination population, the detection rates of normal and elevated ALT were 17% and 143% respectively. The detection rates of acute hepatitis, chronic hepatitis and cirrhosis were 48%, 43% and 47% respectively. Of the 11 positive patients, 3 had normal ALT and 8 had abnormal ALT. Of the 8 patients with ALT abnormalities, 6 were present with HBV infection, 1 with current infection with HCV, and only 1 with NA-G hepatitis. Conclusion Low levels of TTV infection can be detected in Chinese healthy people and liver disease patients. However, it seems that only a slight increase in transaminases in individual patients is caused. The pathogenicity of TTV may be weak or need other factors synergistic pathogenic.