Читать книгу Basic Virology - Martinez J. Hewlett - Страница 73

We have noted in Chapter 1 that while prions are not viruses, many of the principles developed for the study of viral diseases can be applied to study of the pathology of prion‐associated diseases. The prion‐caused encephalopathies are, perhaps, the extreme example of an infectious disease with a long incubation period. Periods ranging from 10 to 30 years between the time of exposure and onset of symptoms have been documented. Prion‐induced encephalopathy does not lead to any detectable immune response or inflammation, probably because the prion is a host protein and the CNS is isolated from normal immune surveillance. The course of the disease is marked by a slow, progressive deterioration of brain tissue. Only when this deterioration is significant enough to lead to behavioral changes can the disease be discerned and diagnosed. No treatment or vaccination strategy is available at this time for human prion diseases, but a partly successful vaccine to prevent prion‐mediated chronic wasting disease of cervids (deer and elk) has been developed.