  We consider a spatial model related to bond percolation for the spread of a
disease that includes variation in the susceptibility to infection. We work on
a lattice with random bond strengths and show that with strong disorder, i.e. a
wide range of variation of susceptibility, patchiness in the spread of the
epidemic is very likely, and the criterion for epidemic outbreak depends
strongly on the disorder. These results are qualitatively different from those
of standard models in epidemiology, but correspond to real effects.
