Most hepatitis cases are caused by one of the five main hepatitis viruses, A-E, "but in the U.S. alone, it is estimated that there are 68,000 cases of post-transfusion hepatitis of unknown etiology still taking place among blood recipients," says Isa Mushahwar, who served as distinguished research fellow and director of the Virus Discovery Group, Abbott Laboratories, North Chicago, Ill., until his retirement in April. Mushahwar is now a consultant for the group, which was established in 1993 to look for a new hepatitis virus to account for all the unexplained cases of hepatitis.
Because of its speculated causal link to hepatitis, TTV quickly became the object of intense scrutiny for Mushahwar and his colleagues. They were the first research team to reveal the virus' complete nucleotide sequence, circular nature, and certain biochemical and biophysical characteristics. They found that even though the new virus shares some structural similarities with viruses ...
