In medieval europe, it took a few years for the black death to consume all of europe. in 2009 the h1n1 disease spread all over the world in a few months. considering the information on the map, how might the h1n1 virus have spread so quickly throughout the world?
the virus was spread throughout the world by flocks of migratory birds.
the virus was spread throughout the world via international airline travel.
the virus was spread throughout the world via contaminated meat.
the virus was spread throughout the world by infected street