HTLV-1/2 in Indigenous Peoples of the Brazilian Amazon: Seroprevalence, Molecular Characterization and Sociobehavioral Factors Related to Risk of Infection

Abstract

HTLV-1/2 infection is endemic in Indigenous peoples of the Americas. Its origin is attributed to the migratory flow of Amerindian ancestral peoples. The present study aimed to investigate the seroprevalence of HTLV-1/2 infection in Indigenous peoples of the Brazilian Amazon. A total of 3350 Indigenous people belonging to 15 communities were investigated. The investigation was performed using serological (ELISA), molecular (qPCR) and confirmatory (Western blot and/or Inno-Lia) tests to detect and differentiate the infection. The seroprevalence was 8.3% for HTLV-1/2 infection, with 0.1% of individuals seropositive for HTLV-1 and 8.1% for HTLV-2. The prevalence of infection was statistically higher in women (10.1%) than in men (6.5%) (p = 0.0002). This female predominance was observed in all age groups; in females the prevalence was significant from 41 years old (p < 0.0001) and in males from 51 years old (p < 0.0001). Here, we present a prevalence of HTLV-1/2 among Indigenous peoples of the Brazilian Amazon. The endemic infection in these groups must reflect the different epidemiological profiles observed in these peoples, such as sexual transmission through rejection of condom use, breastfeeding, especially in cases of cross-breastfeeding, and the high rate of pregnancy in the villages.

Unique evidence of atypical lymphocytes and flower cells in indigenous Xikrin do Bacajá people infected with HTLV-2

“…The present study aimed to investigate the occurrence of atypical lymphocytes in samples of indigenous people infected with HTLV-2 in the Xikrin do Bacajá (Kayapó) indigenous community where the virus is hyperendemic [11,12].…”

“…In 2020, a health support expedition was directed to A new visit occurred in 2021, when blood smear slides were collected from 25 indigenous individuals (11 men and 14 women) formerly diagnosed with HTLV-2 infection by Western blot and qPCR [12]. The slides were stained using the Leishman method and then analyzed for lymphocyte morphology under an optical microscope (100x).…”

“…The Virus Laboratory has kept the Kayapó villages under close surveillance for HTLV-2 infection and disease since the 1990s [11][12][13][14]. A major investigation was recently performed, and the seroepidemiological results of this visit, together with those from 11 other indigenous villages, were reported by Abreu et al [12].…”

“…The Virus Laboratory has kept the Kayapó villages under close surveillance for HTLV-2 infection and disease since the 1990s [11][12][13][14]. A major investigation was recently performed, and the seroepidemiological results of this visit, together with those from 11 other indigenous villages, were reported by Abreu et al [12]. The endemic presence of HTLV-2 in communities comprising the Kayapó ethnic group has been described since 1992 [15]; however, neither clinical nor hematological laboratory alterations could ever be attributed to HTLV-2 infection.…”