  We study fluctuations of conserved charges including baryon number, electric
charge, and strangeness as well as the correlations among these conserved
charges in the 2+1 flavor Polyakov--Nambu--Jona-Lasinio model at finite
temperature. The calculated results are compared with those obtained from
recent lattice calculations performed with an improved staggered fermion action
at two values of the lattice cutoff with almost physical up and down quark
masses and a physical value for the strange quark mass. We find that our
calculated results are well consistent with those obtained in lattice
calculations except for some quantitative differences for fluctuations related
with strange quarks. Our calculations indicate that there is a pronounced cusp
in the ratio of the quartic to quadratic fluctuations of baryon number, i.e.
$\chi_{4}^{B}/\chi_{2}^{B}$, at the critical temperature during the phase
transition, which confirms that $\chi_{4}^{B}/\chi_{2}^{B}$ is a useful probe
of the deconfinement and chiral phase transition.
