A new research has found strong evidence that the recent, alarming clusters of sudden-onset paralysis cases, most of them in California and Colorado, were caused due to the same virus that was responsible for hundreds of severe respiratory infections in US children previous year.

In a study published on Monday, UCSF scientists said the main reason for worry is that the enterovirus identified in the research is a new strain that seems to have mutated to become more polio-like, has raised the prospects of outbreaks of the disease in future.

Dr. Charles Chiu, head of the viral diagnostics laboratory at UCSF and lead author of the paper, said, "The changes were always in the direction to make it more similar to polio. I want to make sure we don't alarm people. There's a chance this virus may never come back, which would be the best-case scenario. But we certainly need to be prepared".

Many scientists including Chiu have been in the search of Enterovirus D68, which is a relatively common pathogen that leads to the mild symptoms linked to the common cold but can cause more serious illness.

However, doctors in California, including physicians at UCSF and Stanford, two years ago, investigated some cases of sudden-onset paralysis in children, and noted that two patients had Enterovirus D68.

Last year, United States faced a massive wave of severe respiratory infections caused by Enterovirus D68, targeting children. As a result of which, over 1,150 cases, all of them positive for Enterovirus D68, were reported by the end of the year.

Chiu said that it will be very hard to predict what will happen in future. He said that it is certain that enterorvirus will crop up again, but the main question is will it be this strain or another strain. He added that this year is going to be very informative.