Zoonotic diseases are infectious diseases that are shared between humans and other vertebrate animals. Extension professionals often serve as consultants and educators to individuals at high risk of zoonotic diseases, such as participants in 4-H livestock projects. Effective education about zoonotic diseases begins with an awareness of the multitude of challenges that health care professionals face in diagnosing zoonotic disease. This review describes the factors that influence diagnosis of these diseases, as well as potential methods that the Extension professional can use to convert those challenges into effective educational messages.