Polio is a disease which attacks the nervous system, mostly the spinal cord. It causes muscle weakness, most commonly in legs and you can't walk properly.

The common and scientific name of the disease.
The common name for this virus is 'Polio' or sometimes 'infantile paralysis' The real scientific name for it is 'Poliomyelitis'. It comes from Greek languauge literally meaning 'sick spinal cord' because the disease damages the spinal cord.

What causes it?
It is caused with poliovirus, which is a member of the genus interovirus. Polio Virus infects and causes a disease in humans which is called Poliomyelitis. The virus is usually passed genetically and also human-to-human. The virus blocks the immunity system and spreads to the central nervous system which damages the spinal cord.

What are the symptoms? How long do they last? Is it deadly?
It usually doesn't have any specific symptoms, it has different symptoms according to different people. And sometimes, it doesn't have symptoms at all. Polio isn't deadly most of the time.

Can it be cured? If so, how? If not, is there any way that we can at least treat it?
It can't be cured. But to treat it, medications are given to reduce pain and prevent complications. Special nutrition diets are also given to improve conditions. It even takes long term rehabilitation and physical therapies to cure it sometimes if it's too complicated. Even if polio has been treated completely, patients will still suffer from Post-polio syndrome, which means that even if they are cured, their muscles will always be weak and will also look weak. And there is a way to prevent it which is very common called polio vaccine, it prevents human-to-human spread of the disease. About 99% percent of people who have taken that vaccine haven't been infected by polio.