Majority of cases are asymptomatic, only 1% result in flaccid paralysis}Non paralytic form: minor illness of fever, malaise, headache, and vomiting, muscle pains, spontaneous recovery in 10 days}Paralytic form: after the aspecific symptoms, rapid onset (from morning to evening) of asymmetric flaccid paralysis, predominantly of the lower limbs, with ascending progression}Paralysis of respiratory muscles is life threatening (bulbar polio)}Aseptic meningitis may occur as a complication