More on anti-HIV antibodies in Brazilian Indians

Abstract

There have been reports of the detection of antibodies to HIV (human immunodeficiency virus) in sera of Indians living primitively in the Amazon region of French Guiana (De-The et al. 1985) and Venezuela (Rodriguez et al. 1985). These findings have led some investigators to screen sera of Brazilian Indians for anti-HIV antibodies (Galvao-Castro & Pereira 1986; Serpa et al. 1986). Here we report the results of a survey carried out on 307 sera of Amerindians living deep in the Amazonian jungle in the southeast region of Para state between the rivers Xingu and Tocantins in conditions of isolation very similar to those of the tribes screened in Venezuela and French Guiana. We studied 121 sera of the tribe Xikrin do Catete (42.4% of the population) 69 sera of the tribe Xikrin do Bacaja (39.2% of the population) 71 sera of the tribe Paracana do Bom Jardim (52.9% of the population) and 46 sera of the tribe Paracana do Marudjewara (58.9% of the population). All sera were collected from adults. All 307 samples were collected in 1985 and screened for anti-HIV antibodies in 1986 by enzyme-linked immunosorbent assay (Organon and Electro-Nucleonics). All were negative except for 10 sera which showed low reactivity (between 1.1 and 3.5 times the cutoff). Nevertheless when tested by the Western blot technique (Biotech Research) all were negative. These results are consistent with those reported by other authors who also failed to find anti-HIV antibodies in other Brazilian tribes. These surveys indicate that anti-HIV seropositivity is not generally common among Brazilian Indians living in the Amazon region. However further surveys should be made near the borders between Brazil and Guiana or Venezuela. (full text)