The passage tells that CJD is a result of an extensive nerve cell damage (lines 15-17). The passage also tells us that the damage occurs because prions that exhibit the abnormal shape have an ability to replicate themselves by initiating a chain reaction that induces normally shaped prions to transform themselves upon contact, and this cascade of transformations produces a thread like plaque that collects in the brain and destroys nerve cells (lines 30-39). Since the brain damage associated with CJD is a result of this cascading transformation, we can infer that if prions were unable to reproduce themselves, they would not cause the nerve cell damage.
