Porcine encephalomyocarditis virus strain BD2 isolated from northern China is highly virulent for BALB/c mice.

Encephalomyocarditis virus (EMCV) can cause acute myocarditis in young pigs or reproductive failure in sows. The BD2 strain was isolated from the suspected piglets with EMCV in China. In order to establish an experimental animal model of EMCV, eight-weeks-old male BALB/c mice were intraperitonealy inoculated with 0.1 ml of 4×10(5) TCID50 suspension of the EMCV. Infected mice demonstrated hind limb paralysis, and movement disorder. The mortality rate of the infected group was 100% during the one-week observation period. The viral load in the brain of challenged mice gradually increased, with a peak level being 6.53 log CCID50/0.1 ml 5 days post infection. The pathological injury in infected mice was presented as neuronal necrosis. Brown positive staining could be detected in the cytoplasm of cerebral neurons. These results indicate that the porcine EMCV isolated from China could replicate in brain tissues and induce acute encephalitis in BALB/c mice.