Validation of meat inspection results for Taenia saginata cysticercosis by PCR-restriction fragment length polymorphism

Bovine cysticercosis is a zoonosis caused by the larval stage (cysticercus) of the human tapeworm Taenia saginata. Infected cattle is an important food safety issue besides an economic concern. Humans get infected by eating raw or under-cooked meat containing viable cysticerci. Visual meat inspection of bovines is the only public health measure implemented to control transmission to humans, but it lacks sensitivity and objectivity. It may underestimate the prevalence of the disease by a factor 3 to 10. Furthermore, the success of the method depends on the expertise of the meat inspector as well as on the stage of development of the cysticerci. The focus of this study was to develop and explore the usefulness of a PCR assay as an objective alternative to evaluate the meat inspector's visual inspection results. Hereto, a PCR was developed for the detection of T. saginata DNA in muscle lesions. Based on the laboratory classification of lesions, almost 97% of viable cysts were confirmed by PCR, while for dead cysts, the percentage was approximately 73%. Taken together, these data demonstrate the difficulties of visual meat inspection and their objective interpretation, emphasizing the need to improve current assays to strengthen the control of bovine cysticercosis.