Trichinosis with severe myopathic involvement mimicking polymyositis. Report of a family outbreak.

We describe an outbreak of trichinosis in 3 members of a rural family. In the 3 patients eating raw pork was the source of infection. They presented with myalgias and severe proximal muscle weakness mimicking polymyositis. The diagnosis was made by demonstration of larvae of Trichinella spiralis in the muscle biopsy and also by the presence of anti-Trichinella antibodies detected by double immunodiffusion in their sera. We call attention to the unusual clinical presentation of trichinosis in our patients that was manifested by severe muscle weakness that may be confused with polymyositis.