Purpose: In this study, a case of BEM in an 18-month-old cow, born and raised in north-west Italy, was investigated; the objective was to determine if BEM was associated with a particular Sarcocystis species, by assessing with a multiplex PCR, the presence of different species inside the lesions (intralesional) and outside the lesions, in normal muscle tissue (extralesional).
Methods: Up to 10mg of material from 17 typical BEM lesions (only the necrotic center) was scalped from different points of the carcass; between 25 and 50 mg of normal muscular tissue was sampled 37 times from the same areas. The DNA extraction and the multiplex PCR were performed following a formerly described protocol.
Results: The presence of S. hominis DNA has been detected in 14 (82%) of samples from lesions, against 4 (10%) from normal muscle. The analysis demonstrated therefore that the presence of S. hominis DNA in the lesions was significantly higher than that in the normal muscle (Fisher test: p=6x10-6); S. cruzi DNA, on the other hand, has been detected in 4 (25%) and 12 (32%) samples from lesions and normal muscle, respectively. None of the samples was found positive for the presence of S. hirsuta DNA.
Significance: The evidence indicates a human source of infection, supporting a causal relationship between S. hominis infection and BEM in cattle.