Evidence of scrapie prions in muscle before animals become ill

Scientists from Berlin and Göttingen discover how scrapie spreads into the muscle

 Transmissible pathogens of prion diseases such as "scrapie" can be detected in the muscles even before the first clinical symptoms appear. The pathogens apparently penetrate from the brain or spinal cord via nerves into muscle fibers, in which they can then spread further, as researchers from the Robert Koch Institute in Berlin and the Institute for Neuropathology at the University of Göttingen, Human Medicine, have now discovered . In the current issue of the respected American "Journals of Clinical Investigation" (Vol. 113, No. 10, pp. 1465-1472), the scientists from Berlin and Göttingen report on the latest results of their experimental scrapie model, which was already used in the In the past, fundamental knowledge about the spread of the pathogen in the body of scrapie-infected sheep and BSE-infected cattle could be gained. The scientists hope that the results of the study, which was funded with third-party funds from the Volkswagen Foundation and the Federal Ministries of Education and Research (BMBF) and Health and Social Security (BMGS), will also provide further insights into the process of the new variant of CJD (Creutzfeldt-Jakob- disease) in humans.

As reported in the Journal of Clinical Investigation, traces of the spread of the pathogen could be detected after about four-fifths of the incubation period in the muscles of the extremities, the masticatory muscle and the tongue of clinically healthy hamsters that had previously been infected with scrapie via food. It was possible to transmit the disease to other animals via muscle tissue. Furthermore, with a further developed detection reaction on the tissue section (PET blot technique), it has been possible to make the prion protein deposits in the muscles and nerves associated with the disease immediately visible and thus to be able to understand the path of the pathogen spread.

Even before transmissible scrapie pathogens were directly or indirectly detectable in the muscles of the animals, they had already infected the brain. If these results could in principle be applied to BSE in cattle and scrapie in sheep, farm animals whose muscle tissue could pose a risk to consumers could be detected and taken out of circulation by the BSE rapid test prescribed in the European Community, the heads of the two research groups, Dr. Michael Beekes (Robert Koch Institute Berlin) and Dr. Walter Schulz-Schaeffer (Institute for Neuropathology, Göttingen) agree.

In addition, the findings underline that, in accordance with the guidelines of the Robert Koch Institute, it is necessary in clinics and medical practice to carefully comply with hygiene measures that prevent accidental transmission of the disease by undetected CJD or vCJD patients.

Source: Berlin / Göttingen [ ukg ]