Afibrinogenemia and Thrombocytopenia in Guinea Pigs

H EMORRHAGE is the outstanding phenomenon observed following the bite by snakes of the Viperidae and Crotalidae families. Subjects bitten by these snakes show local hemorrhage near the site of the bite, slowly extending proximally, and, after death, widespread hemorrhage in many internal organs. In the explanation of the hemorrhage, two mechanisms have been invoked; damage to the vessel wall caused by venom hemorrhagins, 3 tnd blood coagulation disturbances due to the action of venom agents on plasmatic coagulation factors46 and on blcod platelets.7’5 Both intravascular clotting and incoagulability of the blood have been described following the inoculation of snake venoms such as of the Bothrops /araraca,#{176} Echis carinata,1 Vipera us’ ‘ 2 and Crotalus ada man teas, ‘ possessing various coagulation-promoting, coagulaticn-inhibiting and fibrinolytic activities! In a study reported from this laboratory on the venom of Echis colarata, a snake prevalent in the Middle E ist,:i evidence has been obtained that the hemorrhages induced by this venom are primarily due to the action of its hemorrhagins on the vessel wall. Injection into mice of Echis colorata venom caused widespread hemorrhage, afibrinogenemia and severe thrombocytopenia. When, however, the venom was treated with specific antivenin, the mice were protected from hemorrhage and death, while afibrinogenemia and thrombocytopenia did occur. In the present communication we report observations on the afibrinogenemia and thrombocytopenia induced by Ecliis colorata venom in the guinea pig. Also in this animal it was possible to separate the hemorrhagic from the coagulation-disturbing action of the venom. Evidence was obtained that this venom contains agents able to produce afibrinogenemia by two different mechanisms : fibrinogenolysis and intravascular clotting followed by fibrinolysis.