Runting Syndrome in Mice Inoculated With Polyoma Virus

Summary

Wasting disease was observed in (C3H × AKR)F₁ hybrids and in C3H mice inoculated at birth with high doses of polyoma virus. Evidence is presented that the induction of runting depends on the dose of virus inoculated as well as on the age at which the animal is infected. The age dependency could be correlated with a difference in virus multiplication in mice inoculated at different ages and might indicate that the virus growth must attain a certain threshold in the organs to induce runting. The autopsy and histological examination of the runted mice revealed visible lesions in the lymphoid tissues. These lesions consisted mostly of atrophy of the Peyer's patches and depletion of lymphocytes in the cortex of the lymph nodes and in the spleen. Thymic lesions were observed in severe cases of runting. A decrease of circulating lymphocytes was observed in the peripheral blood. The experiments support the concept that depletion of lymphocytes is a basic phenomenon in all runting syndromes. They also indicate that a virus may be the primum movens in the induction of runting.