Feasibility For Eradication
One of the problems of testing for the eradication of polio infections is that the majority of cases do not show any clinical symptoms. They are asymptomatic. Less than 1% of polio infections lead to paralysis and most of the cases that go on to paralysis are caused by the type 1 poliovirus. Type 1 is also the one most responsible for outbreaks of epidemics. Along with type 3 it represents probably less than one case out of a thousand polio infections.
Another problem in tracking the polio virus is that there are other viruses (Enteroviruses) that create symptoms that are exactly like the ones created by the polio viruses. There are also some unusual types of symptoms in some polio infections that resemble a disorder known as Guillain-Barre syndrome. Only a careful laboratory examination that includes isolating the viruses from the patient's stool can be considered for giving a correct diagnosis of the infection. The presence of such laboratory facilities, especially in backward areas, therefore, becomes an important factor in the program to eliminate infections from polio viruses.