The latest Tweet by Bloomberg states, 'South Africa has identified an imported case of Lassa fever, a hemorrhagic virus harbored by rats and transmitted to humans ...' South Africa Has Identified an Imported Case of Lassa Fever, a Hemorrhagic Virus Harbored ... - Latest Tweet by Bloomberg.The latest Tweet by Bloomberg states, 'South Africa has identified an imported case of Lassa fever, a hemorrhagic virus harbored by rats and transmitted to humans ...' South Africa Has Identified an Imported Case of Lassa Fever, a Hemorrhagic Virus Harbored ... - Latest Tweet by Bloomberg. South Africa Has Identified an Imported Case of Lassa Fever, a Hemorrhagic Virus Harbored ... - Latest Tweet by Bloomberg | LatestLY