The Polio Virus Polio infection is known only to occur in human beings. Therefore, it is potentially eradicable disease. Polio virus can survive for long periods in the external environment. There are three types of polioviruses or stereotypes 1,2 and 3. Most outbreaks of paralytic polio are due to type 1 virus, .
Most infections are sub-clinical.
It is the mild and sub-clinical infection that play a dominant role in the spread of infection. All Rights Reserved.