Viral Diseases of the Digestive System

This chapter discusses three virus infections affecting the digestive system of mice and their properties: (1) epizootic diarrhea of infant mice (EDIM), (2) reovirus 3 infection, and (3) murine hepatitis virus infection (MHV). All three infections may cause serious, debilitating, and sometimes fatal diarrheal disease in nursling and weanling mice. Mice of all ages can be infected by the EDIM virus but overt disease is restricted to animals up to about 12–13 days of age at the time of first exposure. The EDIM virus is worldwide in distribution. Its prevalence is difficult to estimate because serologic tests have not been readily available, and it is not customary to sacrifice animals for the purpose of examining the appearance of their intestinal tract or for electron microscopic visualization of fecal contents. The acute disease of reovirus 3 infection affects mainly sucklings and weanlings, whereas the chronic disease is encountered in animals over 28 days of age. The MHV virus, on the other hand, has been found to affect cotton rats, rats, and hamsters.