Disclosed herein are methods for treating or preventing a disease comprising administering a pharmaceutical composition comprising a therapeutically-effective amount of nitazoxanide to a subject having the disease, wherein the disease is causally linked to infection by one or more pathogens selected from the group consisting of members of the genus Ebolavirus, members of the genus Marburgvirus, members of the species dengue virus, human immunodeficiency viruses 1 and 2, and members of the species Mycobacterium tuberculosis.