2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/21688We develop simple models for the global spread of infectious diseases, emphasizing human mobility via air travel and the variation of public health infrastructure from region to region. We derive formulas relating the total and peak number of infections in two countries to the rate of travel between them and their respective epidemiological parameters.13 pages, 7 figures (eps), latexCondensed MatterHigh Energy Physics - PhenomenologyBiological PhysicsPopulations and Evolutiontext