Health authorities have launched a 'ring immunisation' drive here after reports of a 5-year-old migrant boy suffering from acute flaccid paralysis (AFP), one of the symptoms of polio.

The symptoms were detected in Vishal Sharma in Gopalganj district of Bihar but the ring immunisation mop-up was launched in Model Town area as the child had stayed in the locality 20 days ago before returning there, officials said today.

Three medical teams had fanned out to administer door-to-door polio drops to under-five children in the area, Civil Hospital senior medical officer Yash Mitra said.