What term describes a highly contagious disease that can spread rapidly across borders?

The term that describes a highly contagious disease capable of spreading rapidly across borders is transboundary. Transboundary diseases are significant because they can impact not only the health of animals but also human populations and economies, often requiring international cooperation for their control and prevention. Examples of such diseases include foot-and-mouth disease and avian influenza, which have the potential to disrupt trade and public health on a global scale.

In contrast, the other terms refer to different concepts. Endemic describes a disease or condition regularly found and consistently present in a particular geographic area. Exotic refers to diseases that are not native or regularly found in a region, while epizootic describes an outbreak of disease in animal populations but doesn't specifically indicate the ability to cross international borders as transboundary does. Hence, the correct term that encapsulates the rapid spread across borders is indeed transboundary.