An Epidemiological Study on TT Virus Infection in Egypt

TT virus (TTV) is a newly isolated virus. Studies of TTV infection in Asia, Europe and North America have shown its existence in varying prevalence. However, there is no available data from any of the African countries. Methods: TTV DNA in serum was assessed by semi-nested polymerase chain reaction involving 24 patients with chronic hepatitis B, 72 patients with chronic hepatitis C, 39 patients with schistosomal liver disease, 47 patients on maintenance hemodialysis, and 109 volunteer blood donors in Egypt. Results: A generally high prevalence of TTV viremia was observed in all of the studied groups. The prevalence of TTV DNA in patients on hemodialysis (58%) was significantly (P = 0.001) higher than that in blood donors (29%). On the other hand, the prevalence in chronic hepatitis B (46%), chronic hepatitis C (31%) and in schistosomal liver disease (36%) did not differ from that in blood donors. Clinical background including mean age, sex distribution, history of blood transfusion and mean alanine aminotransferase level did not differ between TTV DNA positive and negative individuals in any of the groups studied. Ultrasonographic evidence of liver cirrhosis was seen similarly in both TTV positive and negative patients with chronic liver diseases. TTV infection was not associated with infection with either hepatitis B or C virus in patients on hemodialysis or in blood donors. The only difference observed was the higher serum concentration of HCV RNA in TTV DNA positive compared to negative patients with chronic hepatitis C (3.0±1.4 vs. 4.0±0.9, P = 0.001). Conclusion: TTV also exists in Egypt in a generally high prevalence in the different populations studied like that reported in Japan. TTV infection was found not to be associated with the risk factors related to blood exposure and also it did not exhibit any pathogenic effect on liver disease. At last, infection with TTV is not associated with that of HCV and their route (s) of transmission seems to be different. © 1999, The Japan Society of Hepatology. All rights reserved.