What is post polio, and where is it coming from since people in the u.s. don't get polio anymore?

Recurrent weakness: Post polio occurs in those who a generation or more ago got polio with some degree of dysfunction, but who recovered and were leading normal lifestyles. But their weakened systems gradually have worn out given the extra strain on the remaining parts of their muscle system. So in advanced age, some of the weakness returns, even though the disease is long gone.

Post Polio Syndrome: Post Polio Syndrome is a group of symptoms that present in 25to50% of Polio Survivors many years after they were infected with polio virus and survived.Even though there is no polio in USA for last several years there are 254000 polio survivors living in USA and many have Post Polio Syndrome