We consider single equations and systems of reaction-diffusion equations depending on small parameter. These equations are generalizations of the Kolmogorov-Petrovskii-Piskunov equation. Using the large deviation principle, we describe the asymptotic behavior of solutions.
Mark Freidlin. "Coupled Reaction-Diffusion Equations." Ann. Probab. 19 (1) 29 - 57, January, 1991. https://doi.org/10.1214/aop/1176990535