Pakistan's premier fast bowler Mohammad Amir caught a viral infection which turned out to be suspected chicken pox. The infection has seemed to put brakes on Amir's journey for the World Cup spot.
Mohammad Amir was not named in Pakistan's squad for the ICC Cricket World Cup 2019, but he was part of the squad for England series. His performance in the ODI series would have allowed him to make his way to the World Cup.
There is no official decision from the management that whether Amir is completely out of the ODI series or not. Fans are dearly praying for the miracle to happen so they can see Amir in action before the mega-event.