A murine model of polymyositis induced by coxsackievirus B1 (Tucson strain).

A murine model of polymyositis induced by coxsackievirus B1, Tucson strain (CVBT) is described. Intraperitoneal CVBT inoculation of CD 1 Swiss mice less than 48 hours old resulted in proximal hindquarter weakness that was first apparent 7 days after viral challenge and persisted for more than 10 weeks. Electromyographic and histologic evidence of a continuing myositis was present during this entire period of time. However, virus was not detectable later than 2 weeks post infection, despite clinical progression of disease. The finding of electromyographic and histologic abnormalities in CVBT-infected mice, long after virus had cleared and neutralizing antibody production evoked, suggests that persistent myositis may be immunologically mediated, triggered by the initial acute viral infection.