The EU said today it has asked Spain to explain how a nurse treating Ebola patients in Madrid contracted the deadly disease the first known case of transmission outside Africa. The European Commission 'sent a letter yesterday to the Spanish health minister to obtain some clarification' of how this had happened despite all the precautions taken a spokesman said. 'There is obviously a problem somewhere' Commission spokesman Frederic Vincent said at a time when all European Union member states are supposed to have taken measures to prevent an Ebola outbreak. Tests confirmed that the nurse had been infected with the