A Dutch doctor who contracted Lassa hemorrhagic fever in Sierra Leone after treating patients has died in hospital, while a second doctor is undergoing treatment, the top Dutch health official said Sunday. The unnamed doctor was flown back to the Netherlands on Tuesday and had been treated at a special isolation ward at a hospital in Leiden near Schiphol airport. “The patient… which has been treated in strict isolation, has died last night,” Dutch Health Minister Bruno Bruins said. “A …