Crimean hemorrhagic fever is differentiated from other hemorrhagic fevers, influenza, leptospirosis, meningococcemia, typhoid fever, surgical diseases with the syndrome of "acute abdomen"; as well as from thrombocytopenic purpura (Werlhof's disease) with a characteristic subacute onset, lack of temperature reaction, hemorrhagic rash from small petechiae to large ecchymoses on the flexor surfaces of the limbs, trunk, frequent nosebleeds and other bleeding, hypochromic anemia, leukocytosis, thrombocytopenia and the absence of changes in the cardiovascular system.