  We investigate the temperature dependence of the shear and bulk viscosities
and their ratios to the entropy density via a continuum QCD approach. We
calculate the pion mass and decay constant in the framework of Dyson-Schwinger
equations of QCD and the pion thermal width by combining with Roy equations. We
obtain then the variation behaviors of the viscosities, especially a novel
feature of the bulk viscosity, with respect to temperature.
