Eosinophilic myositis resulted from Sarcocystis infection in prime marbled beef of Japanese black cattle

Tohru Kimura

doi:10.5455/vetworld.2011.500-502

Abstract

Partial changes of color (greenish to brownish) were found in prime marbled beef of Japanese black cattle. The disseminated lesions of the skeletal muscles were histopathologically examined in relation to Sarcocystis infection. The lesions in the muscles showed granulomas with inflammatory cell infiltration. The sarcocysts had a distinct wall, which was radically striated by palisading villar protrusions. The sarcocyst wall was surrounded by degenerative eosinophils and necrotic muscle fibers. In conclusion, eosinophilic myositis in prime marbled beef of Japanese black cattle resulted from Sarcocystis spp. infection. The muscular lesions were characterized by the presence of granulomas and capsulated sarcocysts surrounded by numerous eosinophils.

Highlights

Previous studies suggested that Sarcocystis spp., often found in association with granulomatous myositis, should be responsible for eosinophilic myositis (Jensen et al, 1986; Gajadhar et al, 1986; Gajadhar and Marquardt, 1991; Wouda et al, 2006)
The small disseminated lesions were a typical form of eosinophilic myositis which resulted in carcass condemnation (Figure I)
The granulomatous lesions had a central core consisting of degenerative eosinophilic leucocytes and remnants of necrotic skeletal muscle fibers

Summary

Introduction

Previous studies suggested that Sarcocystis spp., often found in association with granulomatous myositis, should be responsible for eosinophilic myositis (Jensen et al, 1986; Gajadhar et al, 1986; Gajadhar and Marquardt, 1991; Wouda et al, 2006). Most investigators describe a high prevalence of Sarcocystis infection in heart, esophagus, diaphragm and tongue of slaughtered cattle. The skeletal muscles are the most often eaten parts of beef, the prevalence of Sarcocystis is relatively low in these muscles. Skeletal muscles are not severely affected by Sarcocystis. The prevalence of Sarcocystis spp. cysts was lower in Japanese beef (6.31%) than in beef imported from America (36.78%) or Australia (29.49%) (Ono and Ohisumi, 1999). The disseminated lesions of the skeletal muscles were histopathologically examined in relation to Sarcocystis infection

Materials and Methods

Results

Discussion