Human T-cell lymphotropic virus type II in Guaraní Indians , Southern Brazil

Human T-cell lymphotropic virus type II (HTLVII) is found in many New World Indian groups on the American continent. In Brazil, HTLV-II has been found among urban residents and Indians in the Amazon region, in the North. Guaraní Indians in the South of Brazil were studied for HTLV-I/II infection. Among 52 individuals, three (5.76%) showed positive anti-HTLV-II antibodies (enzyme-linked immunosorbent assay and Western blot). This preliminary report is the first seroepidemiological study showing HTLV-II infection among Indians in the South of Brazil. HTLV-II; HTLV-II Infections; South American Indians; Seroepidemiologic Studies Human T-cell lymphotropic virus types I and II (HTLV-I and HTLV-II) are retroviruses belonging to the deltaretrovirus genus. HTLV-I is prevalent worldwide and HTLV-II occurs among Native American populations, in sub-Saharan Africans (Pygmies), as well as among intravenous drug users (IDUs) in Europe and the United States 1. High HTLV-II infection prevalence rates have been found in several Amerindian groups. Table 1 shows the data from outside Brazil. Twentyeight prevalence rates are listed, and although in about two-thirds the numbers are below 10.0%, particularly high frequencies (greater than 30.0%) have been observed in the Guahibo of Colombia, the Chorote and Chulupi of the Chaco region, and the Alacaluf of southern Chile. The vast majority of Native Indians in southern South America live in Brazil, Paraguay, Argentina, and Chile. In South America, only Uruguay has no remaining indigenous population. Many South Amerindians live in the remote jungle of the Amazon basin in the North, such as the Kayapó and the Krahô 1,2. Native tribes from northern Brazil are known to have endemic HTLV-II infection seroprevalence, and Table 2 presents relevant figures. As before, some two-thirds show values below 10.0%, but the Kayapó have a particularly high frequency (32.0%-33.0%). The Guaraní Indians inhabit extensive areas of Paraguay, Bolivia, and Argentina. The Menna-Barreto M et al. 1948 Cad. Saúde Pública, Rio de Janeiro, 21(6):1947-1951, nov-dez, 2005 Table 2 Seroprevalence of HTLV-II among Brazilian Amerindians. Region Ethnic group Linguistic Number HTLV-II positive subjects Author* group of subjects n % Amazon Kayapó Jê 264 88 33.3 24

Human T-cell lymphotropic virus types I and II (HTLV-I and HTLV-II) are retroviruses belonging to the deltaretrovirus genus. HTLV-I is prevalent worldwide and HTLV-II occurs among Native American populations, in sub-Saharan Africans (Pygmies), as well as among intravenous drug users (IDUs) in Europe and the United States 1 .
High HTLV-II infection prevalence rates have been found in several Amerindian groups. Table  1 shows the data from outside Brazil. Twentyeight prevalence rates are listed, and although in about two-thirds the numbers are below 10.0%, particularly high frequencies (greater than 30.0%) have been observed in the Guahibo of Colombia, the Chorote and Chulupi of the Chaco region, and the Alacaluf of southern Chile.
The vast majority of Native Indians in southern South America live in Brazil, Paraguay, Argentina, and Chile. In South America, only Uruguay has no remaining indigenous population. Many South Amerindians live in the remote jungle of the Amazon basin in the North, such as the Kayapó and the Krahô 1,2 . Native tribes from northern Brazil are known to have endemic HTLV-II infection seroprevalence, and Table 2 presents relevant figures. As before, some two-thirds show values below 10.0%, but the Kayapó have a particularly high frequency (32.0%-33.0%).
The Guaraní Indians inhabit extensive areas of Paraguay, Bolivia, and Argentina. The Table 2 Seroprevalence of HTLV-II among Brazilian Amerindians.

Region
Ethnic  Guaraní and Kaingáng are the two most numerous tribes in southern Brazil. Culturally, the Guaraní and Kaingáng are quite different, beginning with their languages, which are mutually unintelligible. The Kaingáng language belongs to the Jê family, while Guaraní is classified in the Tupí-Guaraní family. Both have been living in southern Brazil and neighboring countries for centuries and have been in contact with non-Indians since colonial times. Nevertheless, intermixture with neo-Brazilians is not high, mainly due to the fact that they generally live on reservations especially established for them. About 3,000 Guaraní Indians, scattered over 27 localities, presently live in Southern Brazil. Of these, two-thirds speak the Mbyá dialect and one-third the Nandeva dialect 3 . The present sample was obtained among Guaraní Mbyá-speaking subjects living in Rio das Cobras, Laranjeiras do Sul, State of Paraná (25º20'S, 52º30'O) in the South of Brazil ( Figure  1). The total Guaraní population on this reservation was estimated as 418 3 . Blood from 100 individuals was collected with anticoagulant and refrigerated as quickly as possible. At the laboratory in Curitiba, red cells and plasma were separated, and the latter was immediately frozen at -20 o C. Afterwards, aliquots were sent under refrigeration to Porto Alegre and kept frozen there since 1988 3 .
In 2001, plasma samples remaining from 52 individuals (28 women and 24 men) were screened for HTLV-I/II by an enzyme-linked immunosorbent assay (Murex HTLV-I+II, GE80/ 81, United Kingdom) and positive samples were further studied by Western blot (HTLV blot 2.4, Genelabs Diagnostics, Singapore). The three positive samples (2 males and 1 female) were typed as HTLV-II according to the manufacturer's instructions, showing a prevalence of 5.76%. Unfortunately there are no cells available to perform molecular studies.
Southern Brazil is geographically and ethnically closely related to the North of Argentina and South of Paraguay, both being areas wellrecognized as endemic for HTLV-II. To our knowledge, this is the first study demonstrating HTLV-I/II infection among Amerindians from the South of Brazil, suggesting the Guarani as an endemic group for these viruses. Further studies will focus on molecular and phylogenetic analyses in a larger number of samples.