Nice Shindo

Human Retroviruses (HIV and HTLV) in Brazilian Indians: Seroepidemiological Study and Molecular Epidemiology of HTLV Type 2 Isolates

To investigate serological, epidemiological, and molecular aspects of HTLV-1, HTLV-2, and HIV-1 infections in Amerindian populations in Brazil, we tested 683 and 321 sera from Tiriyo and Waiampi Indians, respectively. Both HIV-1 and HTLV-2 infections were detected at low prevalence among the Tiriyos whereas only HTLV-1 was present among the Waiampis, also at low prevalence. Analysis of the nucleotide sequence of the 631 bp of the env gene obtained from the three HTLV-2 isolates detected among the Tiriyos demonstrated by restriction fragment length polymorphism that these viruses belong to subtype IIa. Phylogenetic analysis of this same fragment showed that these sequences cluster closer to HTLV-2 isolates from intravenous drug users living in urban areas of southern Brazil than to the same gene sequence studied in another Brazilian tribe, the Kayapos. Our results confirm the distribution of Brazilian HTLV-2 sequences in a unique cluster I and cluster IIa and suggest that there is a considerable degree of diversity within this cluster. We also report for the first time HIV-1 infection among Brazilian Amerindians.

Brazilian HTLV Type 2a Strains from Intravenous Drug Users (IDUs) Appear to Have Originated from Two Sources: Brazilian Amerindians and European/North American IDUs

In Brazil, HTLV-2 has been detected in blood donors, in intravenous drug users (IDUs) from urban areas, and in Amerindians living in the Amazon basin. Of the three main HTLV-2 subtypes (2a, 2b, and 2d) only subtype 2a has been detected in Brazil. However, a molecular variant of subtype 2a (also called HTLV-2c) characterized by an extended Tax protein has been isolated from Brazilian blood donors, IDUs, and Indians. Here, we analyzed HTLV-2 isolates from 10 IDUs and a Chilean woman living in Salvador, Bahia, Brazil. Sequencing of env, pX, and long terminal repeat (LTR) genes demonstrated that 10 of the isolates are related to the Brazilian subtype 2a molecular variant described previously. We show that most HTLV-2a Brazilian strains comprise a phylogenetic group harboring a considerable degree of diversity within the env region but not within the LTR region. Interestingly, we demonstrated for the first time in Brazil the presence of a subtype 2a in IDUs that is closely related to the prototype Mo but distinct from the Brazilian 2a molecular variant.

Molecular epidemiology of human immunodeficiency virus-1 in the state of Ceará, Northeast, Brazil

We analyzed, by env and gag heteroduplex mobility assay, 149 human immunodeficiency virus (HIV-1) positive samples collected in Ceará during the year 2000. The prevalence of subtype B was 81.2% and the prevalence of subtype F and B/F recombinants were both 2.7%. Eight (5.4%) and 12 (8%) out of 149 samples showed indeterminate results in the env and gag analysis respectively. By FokI restriction fragment length polymorphism, 34% of the subtype B samples were identified as the typical Brazilian subtype B. In the present study, we identified HIV-1 subtype F and B/F in Ceará for the first time. Our results contribute to the understanding of HIV in Brazil, and may prove useful for the development of vaccine candidates.