Wikipedia relies on a community of editors who construct articles related to various topics such as new disease outbreaks. New disease outbreaks are often characterized by emergent and changing information which, in turn, require Wikipedia editors to spend time and effort to retrieve and understand information that is sometimes ambiguous, complex, and contradictory. This makes a good case study for identifying different types of uncertainty, as well as delineating strategies for managing uncertainty. Despite recent research that explores how the general population expresses uncertainty during crisis events on social media platforms, limited work has focused explicitly on how Wikipedia editors express uncertainty while editing articles when knowledge or background information is either incomplete or unknown. Thus, the goals of this study are to identify types of uncertainty expressed by Wikipedia editors during new disease outbreaks, and examine different strategies deployed by Wikipedia editors to manage uncertainty. Our findings may be used to build a theoretically and empirically-driven framework to better understand and manage uncertainty on Wikipedia.