The modern world is more connected than ever possible before. Mass transit, international trade, illegal immigration, each spreads the world's people to different areas of the globe. With these things at a peak of effectiveness, it means that any form of disease can spread across continents and oceans with alarming speed. A disease which can control the infected victims and make them spread it (e.g. a ) will spread even faster. In short, a modern day zombie plague will spread faster and grow larger, and people will be worse off fighting it.