Disease knows no borders. In today’s interconnected world, diseases can spread from an isolated, rural village to any major city in as little as 36 hours. The U.S. cannot protect its borders and the health of its citizens without addressing diseases elsewhere in the world. CDC works 24/7 to protect Americans and save lives around the world by detecting and controlling outbreaks at their source. In addition, CDC helps other countries increase their ability to prevent, detect, and respond to health threats on their own.