The simple mathematical models which describe the progression of a disease
through a well mixed population have been the subject of vast amounts of
study in recent years (Anderson and May 1992). However, despite our fairly
clear understanding of the dynamics produced by these simple epidemiological
systems many problems arise when the underlying assumption of spatial homogeneity
no longer holds: unfortunately this is usually the case. Although many
studies have realised the importance of space to disease spread (Cliff
et.
al. 1981, Durrett 1988, Dwyer 1992, Bolker and Grenfell 1995, Grenfell
et
al 1995, Cliff 1995, Durrett 1995, Metz and van de Bosch 1995 and Mollison
and Levin 1995) generic phenomena are difficult to extract due to the vast
amount of data produced by spatial simulations and the computationally
expensive nature of the problem