ENDEMIC HUMAN T-CELL LEUKEMIA-VIRUS TYPE-II INFECTION IN SOUTHWESTERNUNITED-STATES INDIANS INVOLVES 2 PROTOTYPE VARIANTS OF VIRUS

Human T cell leukemia virus (HTLV) type II is endemic in certain Ameri can Indians, and high rates of infection occur in intravenous drug use rs (IVDUs). North American IVDUs are infected with two distinct varian ts, HTLV-IIa and -IIb. If IVDUs became infected as a result of interac tion with members of an American Indian population, both viral forms s hould be demonstrable in such populations. Nucleotide sequence analysi s of 630 bases of the env gene encoding the gp21 protein was done on D NA from 12 New Mexico Indians (8 Pueblo, 4 Navajo). All samples were t ypical subtype a or b viruses. Seven of the 8 Pueblo and 2 of 4 Navajo had subtype b; the rest had subtype a. The results are compatible wit h an indigenous New World origin for both subtypes of HTLV-II.