New Delhi, Oct 12 (IANS): A suspected case of polio reported in Darbhanga district of Bihar has tested negative for the wild virus, it was announced Thursday.

"The ERC Mumbai laboratory, where the samples were being investigated, confirmed the case as negative this (Thursday) evening," said a statement issued by Unicef India.

The union health ministry, in a statement issued early Thursday, had said the case was suspected to be of wild poliovirus type 3 (WPV3).

As a measure of abundant precaution, the ministry has initiated rolling out an immunization drive in 28 districts of Bihar early next week.

"Bihar has not had any case of WPV3 since January 2010. India has been polio-free since Jan 13, 2011. The WPV3 strain is prevalent in Nigeria and Pakistan," the official said.

The World Health Organisation (WHO) officially removed India from the list of polio-endemic countries early this year, as India has not had a case of polio since January 13, 2011.

India has to report no polio for three consecutive years to be declared polio-free.