Rhabdophis tigrinus IN JAPAN: PATHOGENESIS OF ENVENOMATION AND PRODUCTION OF ANTIVENOM

Abstract

The yamakagashi (Rhabdophis tigrinus), a colubrid snake, is common in Japan. However, largely because the snake is rear-fanged, severe bites occur rarely, and only 29 cases of yamakagashi bites have been reported since 1917. The epidemiological analysis of the severe bites indicates that most of the bites occurred in warmer months, from April to October. Most of the bites occurred in males trying to catch snakes while in residence, in the field and on the road during daylight hours. Systemic symptoms including continuous bleeding from the bite wound, gums, hematuria, ecchymosis of the body, and coagulation abnormalities of the blood are induced by a hemorrhagic factor and prothrombin activator found in the venom; fatalities occur rarely. An antivenom was produced by immunizing rabbits and goats with yamakagashi venom. The γ-globulin separated from the blood of immunized animals (antivenom) was effective at preventing hemorrhage and coagulation abnormalities of the blood of envenomated patients.