Human T-cell lymphotropic virus type-I antibodies in Falashas and other ethnic groups in Israel

Epidemiological studies of the human T-cell leukaemia/lymphoma virus type I (HTLV-I), a type-C retrovirus of the human T-lymphotropic virus family, have used serological surveys to identify population subgroups possessing a high prevalence of naturally occurring HTLV-I-specific antibodies. Studies carried out to delineate the global distribution of the virus have demonstrated natural antibodies to HTLV-I in the serum of healthy donors from specific geographical areas, and have defined viral endemic areas in Japan, the Caribbean basin, Africa and the southeastern United States. Such studies have suggested that the prevalence of HTLV-I antibodies is directly correlated with age, is associated with the clinical syndrome of adult T-cell lymphoma, and is associated with transmission from mother to child. A separate subtype of the human retrovirus, HTLV-II (refs 21, 22), has also been identified. The population of Israel in part comprises groups of immigrants of various ethnic and geographical origins. Because of this, and the fact that Israel has a highly developed public health system, we surmised that the ethnic groups in Israel could be used in a seroepidemiological survey of HTLV infection. The serological survey reported here demonstrates a high prevalence of HTLV-I antibodies in new immigrants from Ethiopia. This previously ethnically and geographically isolated group, the 'Black Jews' or 'Falashas', from the Gondar region in the northern rural highlands of Ethiopia, has the highest endemic rate of HTLV-I yet reported outside Japan.