West Nile virus infection has quickly become a feared cause of neurologic disability and death, particularly when it presents with encephalitis. Recent epidemics in endemic regions of Eurasia and Africa, as well as its recent spread to North America, have highlighted the need for all physicians to be aware of its clinical presentation and course. In particular, because of the increased susceptibility of West Nile virus infection during outdoor activities, as well as during travel to the Middle East and Southeastern Europe, military physicians should be informed about case recognition, management, and prevention to maintain the health of soldiers and their families.