BDNF and major depressive disorder: Altogether, these data reinforce that in chronic infection (T. cruzi), systemic inflammatory abnormalities are associated with canonical alterations in the CNS such as elevation of oxidative stress and neurotransmitters (as Glu) and reduction of neurotrophins (as BDNF) in the CNS, as previously described in non-infectious neurodegenerative disorders such as Alzheimer disease [19,25] and behavioral changes such as depression [21].