Clinical manifestations of mousepox in an experimental animal holding room.

A study of the clinical aspects of mousepox was conducted during the 1979-80 outbreak at the National Institutes of Health. The disease was detected serologically in a room located adjacent to the index room. The index room received animals prior to this outbreak from a noncommercial colony which later was found to be infected with mousepox. The infection was present in the room for at least 6 weeks prior to the completion of the study. The paucity of clinical signs and low mortality were striking when compared to previous descriptions of mousepox in the United States. Only 27 of the 939 mice in the room were infected, and only one of these had typical skin lesions. A few of the mice had non-specific signs such as ruffled hair coat and hunched appearance. Minimal spread of the disease was evidenced by clustering of infected cages on one of five animal racks in the room.