An apparently new lethal virus disease of infant mice.

A hitherto unreported disease of infant mice is described. The agent reproduces upon passage, is filterable, is confined mainly to the gastrointestinal tract in infant and adult mice, causes death in infants and inapparent infection in adults, and is sensitive to mild heat, ether, and sodium deoxycholate. Unique and characteristic morphologic changes occur in the epithelial cells of the intestine in infected infant mice. These consist in the development of multinucleated giant cells designated "balloon cells.".