DEMOGRAPHIC, ETHNIC, AND GEOGRAPHIC DIFFERENCES BETWEEN HUMAN T-CELL LYMPHOTROPIC VIRUS (HTLV) TYPE I-SEROPOSITIVE CARRIERS AND PERSONS WITH HTLV-I GAG-INDETERMINATE WESTERN BLOTS IN CENTRAL-AFRICA

Using stringent Western blot (WB) criteria, human T cell lymphotropic virus (HTLV) type I seroprevalence among 3783 persons from representat ive rural populations of Cameroon averaged 1.1% and was higher in fema les (1.5%) and in Pygmies (2.0%), increasing with age, Furthermore, an HTLV-I Gag-indeterminate WE profile (HGIP), exhibiting strong reactiv ities to p19, p26, p28, p32, p36, and pr 53 but lacking both p24 and e nv reactivity, was observed in 1.6% of the same populations, The preva lence of the HGIP was similar between males and females, did not incre ase with age, and appeared to cluster in tropical forests of southern Cameroon, especially among Pygmies (reaching 4%). These contrasting ep idemiologic features, together with the lack of detection by polymeras e chain reaction of HTLV-I sequences in the peripheral blood mononucle ar cells of the persons with HGIP, strongly suggest that such a WE pro file does not appear to reflect an HTLV-I-related viral infection but possibly an environmental (viral or parasitic) factor endemic in tropi cal rain forest areas.