Similar title to Kryazhimskiy, S., Dieckmann, U. ORCID: https://orcid.org/0000-0001-7089-0393, Levin, S.A., & Dushoff, J. (2007). On state-space reduction in multi-strain pathogen models, with an application to antigenic drift in influenza A. PLoS Computational Biology 3 (8) e159. 10.1371/journal.pcbi.0030159.