Introduction

The words polio (grey) and myelon (marrow, indicating the spinal cord) are derived from the Greek. It is the effect of poliomyelitis virus on the spinal cord that leads to the classic manifestation of paralysis. Poliomyelitis or poliio is a crippling and potentially deadly infectious disease caused by poliovirus that spreads from person to person invading the brain and spinal cord resulting into paralysis. Humans are the only known reservoir of poliovirus, which is transmitted most frequently by persons having infection.

Due to unavailability of any cure till date vaccination is the best way of protection and the only way to control the spread of disease.

Generally ,two basic patterns of polio infection are :

• Minor illness which does not involve the central nervous system (CNS), sometimes called abortive poliomyelitis,
• A major illness involving the CNS, which may be paralytic or nonparalytic

Poliomyelitis generally spreads via the fecal-oral route by ingesting contaminated food or water and the oral-oral  route. In endemic areas, polioviruses can affect the entire human population. The disease has a seasonal transmission in temperate climates, with a peak occurrence during summer and autumn. 

References : www.cdc.gov(link is external)
www.who.int(link is external)
www.nlm.nih.gov(link is external)
www.nhs.uk(link is external)
www.ninds.nih.gov