  We calculate the 2nd and 4th order quark number susceptibilities at zero
baryochemical potential, using a PNJL approach and an approach which includes,
in a single model, quark and hadronic degrees of freedom. We observe that the
susceptibilities are very sensitive to possible quark-quark vector
interactions. Compared to lattice data our results suggest that above $T_c$ any
mean field type of repulsive vector interaction can be excluded from model
calculations. Below $T_c$ our results show only very weak sensitivity on the
strength of the quark and hadronic vector interaction. The best description of
lattice data around $T_c$ is obtained for a case of coexistence of hadronic and
quark degrees of freedom.
