Poliovirus

Introduction

Poliovirus is the virus that causes polio. Most people who get infected with poliovirus will not show any visible symptoms. Some will have flu like symptoms, like sore throat, fever, and stomach pain. A small proportion of people infected with poliovirus may develop more serious problems, like paralysis and meningitis. 

Hosts

Humans.

Transmission / Exposure Route

Poliovirus spreads through person to person contact. The virus lives in an infected person’s throat and intestines. It enters the body through the mouth and spreads through contact with contaminated feces or droplets from a sneeze or cough. Direct contact with objects that have touched feces infected can spread the virus. 

Case Fatality Ratio

The death to case ratio for paralytic polio is generally 2%-5% among children and up to 15%-30% for adults. 

Incubation Period

The incubation period for nonparalytic poliomyelitis is 3 to 6 days. For the onset of paralytic poliomyelitis, the incubation period is between 7 to 21 days 

Microbiology

Poliovirus is a human enterovirus. It is composed of an RNA strand and a protein capsid. The viral particle is about 30 nm in diameter.

Enviromental Survival

They are stable at acid ph. It is rapidly inactivated by heat, formaldehyde, chlorine, and ultraviolet light.