Multicenter cross-sectional study of HTLV-1 prevalence and associated risk factors in epidemiologically relevant groups across Brazil

Abstract

Background: Human T cell lymphotropic virus type 1 (HTLV-1) is highly endemic in Brazil, necessitating surveillance studies to understand its epidemiology. While previous research has focused on either specific cities or populations, there is a need for multicenter studies encompassing epidemiologically relevant populations to ascertain more accurate prevalence rates and predictors of HTLV-1 infection in the country. Methods: We conducted a multicenter, cross-sectional study involving 3,184 participants across seven cities and five study populations in Brazil. Blood samples were collected, and the prevalence of HTLV-1 infection was determined by enzyme-linked immunosorbent assay (ELISA) and Western blot. Binary logistic regression analysis was used to determine risk factors of HTLV-1 infection. Results: Among the total study population, 1,135 (35.7%) were aged >40 years and 1,704 (53.5%) were female. The overall prevalence of HTLV-1 infection was 0.5% (95% CI: 0.3–0.8), with variation observed among the cities or study populations. Factors associated with HTLV-1 infection included age > 40 years (OR, 8.867; 95% CI: 1.824–43.099), female gender (OR, 4.604; 95% CI: 1.184–17.903), and Hepatitis C virus (HCV) infection (OR, 13.995; 95% CI: 2.374–82.506). The identification of older age and female gender, coupled with the high prevalence of HTLV-1 in HIV-positive patients, suggests sexual transmission as the primary route of HTLV-1 infection. Conclusion: Our study reveals varied prevalence rates of HTLV-1 infection across diverse populations and cities in Brazil. The association of older age, female gender, and HCV, emphasizes the need for tailored interventions to prevent HTLV-1 transmission.