Dengue fever and human T-cell lymphotropic virus type 1 infection

Globalization has increased both the number of emergent diseases and the diversity of co-infections, which could in turn mutually influence the pathogenesis of well-known infectious diseases. Here, we report the first series of chronic human T-cell lymphotropic virus type 1 (HTLV-1) patients co-infected with the dengue fever virus. As both of these diseases are immuno-mediated, we anticipated interference in the development of both diseases, with atypical clinical and laboratory parameter results. All the patients had classic dengue fever, and the main outstanding abnormality was leukopenia associated with lymphopenia. Although a mutual influence was expected, dengue fever did not affect the clinical course of HTLV-1 infection, and HTLV-1 proviral loads revealed unpredictable patterns of change.