IL6 and major depressive disorder: Although previous studies suggested both BoDV-1 and pro-inflammatory cytokines IL-6 and IL-8 as possible co-factors in the etiopathology of depression, currently, little is known about cognitive-affective, immunological, as well as neurophysiological changes associated with BoDV-1 infection in humans (Dietrich and Bode, 2008; Dietrich et al., 2005).