Prevalence of infection by human T-cell leukemia virus types I and II in southern Spain.

To assess the spread of human T-cell leukemia virus (HTLV) type I and II in different population groups at potential risk of infection in Spain, a total of 756 subjects were studied: 453 belonging to groups at risk for retrovirus infection, 255 with diseases potentially linked to HTLV-I/II infection and 48 immigrants from endemic areas. An HTLV-I viral-lysate enzyme immunoassay (EIA) with a recombinant transmembrane envelope protein incorporated was used to screen serum samples. Reactive specimens were confirmed by Western blot strips spiked with recombinant proteins that differentiated HTLV-I from HTLV-II. Infection was then verified by the polymerase chain reaction (PCR). Serum samples from 19 of the 756 subjects analyzed (2.5%) were reactive for HTLV by EIA. One of these was from an intravenous drug user (IVDU) in whom HTLV-II infection was confirmed by Western blot and PCR; a specimen from another IVDU showed Western blot reactivity for both retroviruses, but PCR results were negative. Lastly, Western blot confirmed the presence of HTLV in one of the immigrant subjects. Western blot did not verify HTLV infection in the remaining 16 cases, indicating a high rate of nonspecific anti-HTLV reactivity when a second-generation EIA screening test was applied. These results suggest that HTLV is present in Spain among populations at high risk for HTLV, although at a very low rate and restricted to intravenous drug users and individuals immigrating from endemic areas.