Selective Polymyositis Induced by Coxsackievirus BI in Mice

A high-passage laboratory strain of coxsackievirus B1 produced a unique myositis that predominantly and profoundly affected hip extensors and, to a lesser extent, hindquarter knee flexors when inoculated into a strain of random-bred newborn mice of Swiss origin (COH mice). The effect was not observed in BALB/c or C3H mice similarly inoculated. In addition to the differences in susceptibility of the mouse strains, it was found that six different low-passage "field" isolates of coxsackie-virus B1 isolated from infected patients varied considerably in their capability to induce these lesions. Thus, selective myositis which is muscle group-specific can be induced in a mouse model with coxsackievirus B1, and both genetic factors of the host and characteristics of the virus strain play a significant role in the pathogenesis of the myositis.