US Ebola quarantine fuels political row - in 60 seconds
A US nurse who cared for Ebola patients in Sierra Leone is fighting the state of Maine's right to quarantine her.
Kaci Hickox defied the voluntary quarantine order on Thursday by leaving her house for a bike ride.
Ms Hickox insists she is completely healthy and says she will fight the state's decision in court if necessary.
Her case comes amid a growing row between federal and state authorities about US policy on Ebola prevention.
BBC News looks at how the battle against Ebola has become a political football - in 60 seconds.
Video produced by Michael Hirst