Slow infectious diseases are a large group of related neurodegenerative conditions, which affect both humans and animals. The diseases are caused by a heterogeneous group of agents consisting of conventional viruses and the unconven-tional agents that are called prions.
The term “slow” refers to the disease process and not to the replication of the viruses that cause the slow disease. Replication rate of virus is similar to that of most other viruses.
A list of slow infectious diseases caused by prions and conventional viruses is presented in Table 69-1.