To the Editors: We know little about the routes of spread of human T lymphotropic virus type II (HTLV-II). Direct evidence for spread of HTLV-II has been documented only for transfusion (1, 2), but epidemiologic evidence supports its transmission sexually and via contaminated needles in drug users (3, 4). Antibodies to HTLV-II are usually detected by enzyme-linked immunosorbent assay (ELISA) and Western blot reagents prepared from HTLV-I-infected cells.
We have studied family members of patients with documented HTLV-II infection to ascertain the frequency with which close family contacts become infected. Serologic testing of the approximately 4000 donations per month to