Polio, or poliomyelitis, is a highly contagious viral infection that can lead to paralysis, breathing problems, or even death. The term poliomyelitis is from the Greek polios poliÃ³s meaning, grey myelos myelÃ³s referencing the, spinal-cord and itis. Meaning inflammation polio can be classified as either symptomatic. or asymptomatic
1 Prions are proteins that can force conformational changes in natural proteins and seem to cause disease (kuru, new variant Creutzfeldt-Jakob disease, and fatal familial insomnia).  A virus is an obligate intracellular pathogen (meaning that it must live within the cells of its host in order to reproduce).
Source. For bacteria, the term obligate parasite can have at least two distinct meanings. 1  A parasite that naturally only reproduces within a host and cannot be artificially cultured on cell-free media.ource. For bacteria, the term obligate parasite can have at least two distinct meanings. 1  A parasite that naturally only reproduces within a host and cannot be artificially cultured on cell-free media.