The first human retroviruses: are there others?

Abstract

Three related, but very different, retroviruses have recently been identified in man. Human T-cell leukaemia virus (HTLV) type I apparently causes adult T-cell leukaemia. HTLV type II has been isolated only rarely and has not been identified with a disease. HTLV type III is very likely the causative agent in acquired immunodeficiency syndrome.