NIGERIA faces oxygen supply challenges to treat coronavirus patients in parts of the country and unacceptable laboratory delays as case numbers rose to the highest recorded in a single week, health authorities have revealed. The new warnings from Nigerian officials come as the resurgent virus strikes across much of the world, bringing greater caseloads and hospitalisations. "There is an on-going review of the chain for the supply of medical oxygen for our medical facilities across the nation," said Boss Mustapha, chairman of Nigeria's coronavirus task force, naming the capital of Abuja as an area of concern. Labs' "inability to function…