Practising medical specialists such as Addo do not believe this number of unreported cases to be statistically significant.

We visited four out of the six unreported cases; none of those four had sequelae compatible with poliomyelitis.

The notice said NHTSA found that FCA failed to notify owners about defects in two previously unreported cases.

But the police are not often deceived: they soon discover unreported cases, and come with litters and coolies.

The four previously unreported cases aimed to return more than $60 million to consumers, the people said.

Mr Templeton said the agency probably deals with only the tip of the iceberg and it was likely there were more unreported cases.

Experts say the number of unreported cases means the real figure could be closer to 60,000 cases a year.

While the numbers have fallen dramatically in recent years, there are still many unreported cases and it's very sad to see such staggering numbers.

It is 83% higher than last year, when 1,669 cases were reported (more than 480,000 had it, taking into account unreported cases).

Unreported cases mean that the true figure could be higher.