Crimean hemorrhagic fever is differentiated from other hemorrhagic fevers, influenza, leptospirosis, meningococcemia. Typhoid fever, surgical diseases with the syndrome of "acute abdomen"; and also from thrombocytopenic purpura (Verlhof's disease) with characteristic subacute onset, absence of a temperature reaction, hemorrhagic rash from small petechiae to major ecchymosis on the flexor surfaces of the extremities, trunk, frequent nasal and other bleeding, hypochromic anemia, leukocytosis, thrombocytopenia and no changes on the part of cardio-vascular system.