A PANDEMIC is a widespread disease that affects a large number of people across the world, while an EPIDEMIC is a localized outbreak of a disease that affects a large number of people in a particular area. Pandemia is a term used to describe a global PANDEMIC, where the disease has spread to multiple countries or continents. All three terms refer to a large-scale outbreak of a disease, but pandemics and pandemias are more severe and have a greater impact on the population.