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).
(my'ch-É-lÄ­z'Ém) A symbiotic relationship in which each of the organisms benefits. â In obligate mutualism the interacting species are interdependent and cannot survive without each other. The fungi and algae that combine to form lichen are obligate mutualists. In the more common facultative mutualism the interacting species derive benefit without being fully dependent. Many plants produce fruits that are eaten by birds, and the birds later excrete the seeds of these fruits far from the parent plant.