Increasing awareness of human T-lymphotropic virus type-1 infection: a serious, invisible, and neglected health problem in Brazil

Human T-lymphotropic virus type 1 (HTLV-1) was the first retrovirus to be isolated in humans. At least 5–10 million individuals harbor the virus worldwide1. In Brazil, between 800,000 and 2.5 million individuals are infected with HTLV-11,2. The geographic distribution of infection is heterogenous in this country and more pronounced in the North and Northeast, mainly affecting low-income populations2,3. One of the few studies that attempted to estimate the prevalence of infection in a general population was conducted in the city of Salvador, reported to be approximately 1.8%3. Most studies involving Brazilian populations have been performed in specific groups, such as blood donors or pregnant women, and the prevalence in the overall population remains unknown4.