Pathology of Poliomyelitis

Dr Sampurna Roy MD

Poliomyelitis is an acute infection by polioviruses. 

Most infections are asymptomatic, but when the virus invades the central nervous system it destroys lower motor neurons, causing paralysis.

Sporadic infections may be seen at any time, but outbreaks occur mostly in summer.

More recent epidemics have stricken adults as well as children.

Polio was sporadic in earlier centuries, but later became epidemic and subsequently pandemic.

The incidence peaked during the 1950s in many developed countries.

Immunization have stopped its spread in the Western world, but polio remains a major public health problem in many developing countries.

Poliovirus is transmitted in drinking water contaminated with feces.

The virus replicates in the mucosa of the small intestine.

Some virions pass from there into the feces, contaminating water and completing the cycle.

Others enter the bloodstream (viremia) and extend to the spinal cord, where they infect and destroy the anterior horn cells, causing paralysis. 

Further reading:

A fatal neuromuscular disease in an adult patient after poliomyelitis in early childhood: consideration of the pathology of post-polio syndrome.

Poliomyelitis in MuLV-infected ICR-SCID mice after injection of basement membrane matrix contaminated with lactate dehydrogenase-elevating virus.

Vaccine-derived poliomyelitis 12 years after infection in Minnesota.

Concomitant CNS pathology in a patient with amyotropic lateral sclerosis following poliomyelitis in childhood.

Tibial lengthening over humeral and tibial intramedullary nails in patients with sequelae of poliomyelitis: a comparative study.

MRI findings in an infant with vaccine-associated paralytic poliomyelitis.