Antonyms for Ecdemic (opposite meaning)
WordNet sense 1 (of or relating to a disease (or anything resembling a disease) constantly present to greater or lesser extent in a particular locality):
endemicWordNet sense 2 ((especially of medicine) of disease or anything resembling a disease; attacking or affecting many individuals in a community or a population simultaneously):
epidemicFrom the ODE community, based on WordNetadd/edit