Wild mice are considered the principal reservoir hosts but laboratory mice and Syrian hamsters also serve as important natural hosts. Humans, nonhuman primates, dogs, rabbits, guinea pigs, rats, and chickens are also susceptible. Both infected mice and hamsters can have chronic infections with high concentrations of virus shed in urine, saliva, and milk.
Transmission is probably via mucus membranes and broken skin.
Clinical signs in mice vary depending on the strain of virus, strain of mouse and age of mouse. There is lifelong viremia and shedding of virus. Transient runting can occur during the first 3 weeks of life which is sometimes followed by modest growth retardation. At 7-10 months of age, immune complex glomerulonephritis occurs and is characterized by emaciation, rough haircoat, hunched posture, ascites, and possible death. In addition, there is generalized lymphoid hyperplasia and perivascular accumulation of lymphocytes and plasma cells in all visceral organs.