High risk of heterosexual transmission of human T‐cell lymphotropic virus type 1 infection in Brazil

Abstract

Human T-cell lymphotropic virus type 1 is transmitted primarily either through sexual intercourse or from mother to child. The current study investigated sexual transmission and compared the HTLV-1 proviral load between seroconcordant and serodiscordant couples by examining both men and women among the index partners without using subjective criteria to establish the direction of sexual transmission. Between January 2013 and May 2015, 178 HTLV-1-positive patients had spouses, 107 of which had tested partners, thus increasing the initial sample size (46 men and 61 women). Individuals co-infected with HTLV-2 or human immunodeficiency virus were not included in the analysis. From among the included participants, 26 men and 26 women were paired with each other, resulting in 26 seroconcordant couples; 12 seroconcordant couples were formed from another four men and eight women. Forty-three serodiscordant couples were formed from 16 men and 27 women. The rate of seroconcordance was 46.9%. The HTLV-1 proviral load was compared between 19 and 37 seroconcordant and serodiscondant couples, respectively, and the concordant couples showed higher proviral loads (P = 0.03). There were no differences between the groups according to age, relationship length, having a mother or sibling with HTLV-1, race, ethnicity, nationality, education, history of blood transfusion, HAM/TSP, ALT, or hepatitis C virus status. In multivariate analysis, relationship time was shown associated with ocurrence of seroconcordance status. The apparent association between high circulating levels of provirus and seroconcordance rate among couples suggests that proviral loads contribute markedly to the risk of sexual transmission, regardless of gender index.

HTLV‐1 and ‐2 in a first‐time blood donor population in Northeastern Brazil: Prevalence, molecular characterization, and evidence of intrafamilial transmission

“…In fact, although we evaluated a low number of families, epidemiological data, along with molecular results, evidenced that familial transmission of HTLV‐1 and HTLV‐2 occurred in this region. These data are consistent with previously reported findings that also shown silent transmission of these viruses through vertical and sexual routes within family clusters in Brazil …”

Dichotomy in Fatal Outcomes in a Large Cohort of People Living with HTLV-1 in São Paulo, Brazil

“…After the adoption of mandatory national blood screening tests in 1993 and the observed behavioral change from intravenous to inhalation drug abuse, parental exposure to HTLV dropped [4][5][6]. However, our group has documented rates of 40 percent of sexual transmission [7] and of 13 percent of vertical transmission [8,9].…”

Screening for Human T-Cell Lymphotropic Virus (HTLV) in Pregnant Women in the Peruvian Amazon and Systematic Review with Meta-Analysis of HTLV Infection in Peru

“…Human T-cell lymphotropic virus (HTLV) was the first human retrovirus identified. It is mostly sexually transmitted [1] but it can also be shed perinatally by breastfeeding [2] and parenterally through contaminated blood, either following transfusions or by needle sharing among injection drug users [3]. Acute infection with HTLV-1 is followed by longlasting persistence of the virus in all carriers, although clinical manifestations develop only in about 10%.…”