A Cardiomyopathy of BALB/c Mice (Superimposed Infection by Coxsackievirus B-3) 1 2

Summary

We describe progressive cardiomyopathy affecting three, and probably all four substrains of BALB/c (C) mice examined. Cardiac changes are limited to the pericardium and immediately subjacent epicardium of the right ventricle. By 2 months of age, mice have mononuclear infiltrates which progress to a dense exudative pericarditis. Whitish flecks on the pericardial surface can be seen at 6 months, and a calcifying scar persists.

When 10^3.5TCD₅₀ of coxsackievirus B-3 (Nancy) is inoculated intraperitoneally into weanling Swiss or C3H mice, myocarditis without pericarditis results. If the infected mice are BALB/c, myocarditis and right ventricular pericarditis ensues. A calcified fibrotic scar over the right ventricle identical to the end-stage of the inherent lesion appears in coxsackievirus B3 infected mice at about one month of age.

Coxsackievirus B-3 multiplies equally well in the right and left ventricles of C mice, but pericarditis is limited to the right heart. In age-matched controls, the prevalence of calcific right ventricular pericarditis in BALB/c mice inoculated with coxsackievirus B-3 is the same as that of the inherent cardiomyopathy, and it is possible that the early calcific lesion in infected mice occurs in animals who later would have developed a right ventricular pericardial cardiomyopathy.