Clinical, pathologic, and serologic features of an epizootic of mousepox in Minnesota

An epizootic of mousepox in two colonies of mice was described. Clinical signs, morbidity and mortality rates, and necropsy lesions were substantially influenced by husbandry practices, intercurrent diseases (Sendai pneumonia, mouse hepatitis virus), and total body x-irradiation. In one colony, 54 mice were necropsied; 19 mice had cutaneous or visceral lesions of mousepox although none had combined visceral and cutaneous lesions. In the other colony, 20 mice were necropsied, and 10 mice had cutaneous lesions; none had visceral lesions. Sera from 24 mice with the cutaneous form of the disease had no demonstrable HI antibody titer. Experimental mice injected with spleen/liver homogenates from infected colony mice developed typical visceral lesions with numerous poxvirus profiles on electron micrographs and positive HI titers. Mice immunized with vaccinia virus were not susceptible to the disease.