Comparative trends of seroprevalence and seroincidence rates of human T cell lymphotropic virus type I and human immunodeficiency virus 1 in pregnant women of various ethnic groups sharing the same environment in French Guiana.

The objectives of this study were to compare the seroprevalence and seroincidence rates of human T cell lymphotropic virus type I (HTLV-I) and human immunodeficiency virus 1 (HIV-1) in pregnant women in several ethnic groups in French Guiana between July 1, 1991 and June 30, 2001. This study was conducted in the obstetrics unit of the hospital in Saint Laurent du Maroni in a dynamic cohort of 6,921 pregnant women with 11,679 deliveries, with new entrants each year. The overall seroprevalence of HTLV for all women differed between ethnic groups and was restricted mainly to the descendents of fugitive slaves of African origin known as Noir-Marron (181 of 4,266, 4.24%) and to Haitian women (12 of 287, 4.18%). A decrease in the biennial seroprevalence of HTLV-I was observed over time among deliveries of the Haitian women (P = 0.037), but it remained stable among Noir-Marron (P = 0.22). Fifteen of the 17 HTLV-I seroconversions occurred in the Noir-Marron, giving an incidence of 0.18 per 100 person-years. The overall seroprevalence of HIV-1 was higher in the Haitian women (10 of 293, 3.41%) than in the Noir-Marron (34 of 4,310, 0.79%) and Amerindians (4 of 552, 0.72%). A highly significant increase in the biennial seroprevalence of HIV-1 was observed among the deliveries of the Noir-Marron (P = 0.0003), but it remained stable among Haitian women (P = 0.44). Ten of the 13 HIV-1 seroconversions were observed in Noir-Marron, giving an incidence rate of 0.12 per 100 person-years. These data demonstrate the differential spreading of these two human retroviruses among pregnant women in different ethnic groups living in the same environment. While HTLV-I, which is highly endemic in groups of African origin, showed a slight decrease over time in a suspected cohort effect, HIV-1 spread rapidly in an epidemic mode, especially in the groups of the lowest socioeconomic levels.