(Science: disease, virology) An acute viral disease, occurring sporadically and in epidemics and characterised clinically by fever, sore throat, headache and vomiting, often with stiffness of the neck and back. In the minor illness these may be the only symptoms.
The major illness, which may or may not be preceded by the minor illness, is characterised by involvement of the central nervous system, stiff neck, pleocytosis in the spinal fluid and perhaps paralysis. There may be subsequent atrophy of groups of muscles, ending in contraction and permanent deformity.
The major illness is called acute anterior poliomyelitis, infantile paralysis and heine Medin disease. The disease is now largely controlled by vaccines.
Origin: Gr. Myelos = marrow