TOXICOLOGY AND PHARMACOLOGY OF VENOMS FROM POISONOUS SNAKES Toxicology and Pharmacology of Venoms from Poisonous Snakes By JOHN H. BROWN, Ph.D., F.A.C.C.P. Department 01 Pharmacology And Department 01 Medicine Louisiana State University School 01 Medicine New Orleans, Louisiana CHARLES C THOMAS • PUBLISHER Sprin8field • IUinou • U.s.A. PubUshed and Distributed ThroughOut the World by CHARLES C THOMAS • PUBLISHER Bannerstone House 301-327 East Lawrence Avenue, Springfield, Illinois, U.S.A. This book is protected by copyright. No part of it may be reproduced in any manner without written permission from the publisher. ©1973, by CHARLES C THOMAS' PUBLISHER ISBN 0-398-02808-7 Library of Congress Catalog Card Number: 73-229 With THOMAS BOOKS careful attention is given to all details of manufacturing and design. It is the Pubiisher's desire to present books that are satisfactory as to their physical quaUties and artistic possibilities and appropriate for their particular~se. THOMAS BOOKSiVat 'iJetf'flP to those laws of quality that assure ago,!d namearad.good will. Printed in the-United States of America EE-11 PREFACE The study of snakes is a science not unlike other sciences. The expansion of knowledge of snakes is not only important be­ cause of its ecologic relationship to other biological species of animals, but also because poisonous snakes pose a threat to animal life, in general, and man, in particular. Thus poisonous snakes con­ stitute a serious problem in public health in many parts of the world. The toxicities of many snake venoms were reported in the older literature in terms of a minimum lethal dose or MLD, a term which was rather vaguely defined. Thus, a MLD meant the smallest dose of venom killing at least one animal of those used in the study, the dose that would kill half but not all of the animals, or the smallest dose that would kill all of the animals. Since many of the more recently reported values of lethality of snake venoms have been expressed in terms of a standardized index of toxicity, viz. the LD50, and venom of possibly better quality was employed in assessing the latter, and it became ap­ parent that a re-evaluation of toxicity values could be useful to medical science, in general, and pharmacology and toxicology, in particular. The purpose of this monograph was, therefore, to bring to­ gether as many values of lethality of snake venoms as possible, in tabular form. In this way the relative toxicities of these venoms could be shO'vvn factually; too many myths have already pervaded the nonscientific literature concerning the toxicities of snake venoms. Together with the tabulated amounts of venom obtain­ able from poisonous snakes, the LD50 values (derived from mice), with certain assumptions, have been combined to calculate an index of the lethality of certain snake venoms for humans. Some unique correlations between estimated human lethality and the known incidence of mortality have thus been derived. The section on pharmacology is included to explain the lethality of snake v vi Toxicology & Pharmacology of Venoms from Poisonom Snakes venoms using data obtained from representative families and species. To carry out research on venoms, one must either purchase the venoms or extract and process one's own venom. Thus a section has been included to outline techniques of hunting for and housing venomous snakes and extracting their venoms. DEDICATION AND ACKNOWLEDGMENTS This book is dedicated primarily to Nancy who still fears that a snake by any other name is still a snake. Without the insistence by Findlay Russell for investigators to obtain the best possible data on poisonous snake venoms in order to expand the true knowledge of such, I may not have been stimulated to compile this text. The author is greatly indebted to Drs. Sherman Minton and Richard Goris for color photographs. Dr. Minton has long been a pioneer in research on snakes and snake venoms. Finally, it could not have been compiled without the assistance and excellent typing of Mrs. Bea Abene. vii CONTENTS Page PREFACE ............. v DEDICATION AND ACKNOWLEDGMENTS .......... vii CHAPTER 1 DESCRIPTIONS AND DISTRIBUTION OF POISONOUS SNAKES . 3 I. Elapidae ... ....... .... 5 A. Acanthopis (death adders) B. Aspidelaps (shield-nosed snakes) C. Boulengerina (water cobras) D. Bungarus (kraits) E. Callophis and lo,laticora (oriental, long-glanded snakes) F. Demansia (brown snakes) C. Dendroaspis (mambas) H. Denisonia (Australian copperheads) I. Elaps (dwarf garter snakes) J. Elapsoidea (garter snakes) K. H emachatus, Naja, Walterinnesia (co bras) L. Leptomicrurtls, Micrurus, Micruroides (coral snakes) M. N otechis (tiger snakes) N. Ophiophagus (king cobra) O. Oxyuranus (taipan) P. Paranaja (burrowing cobras) Q. Pseudechis (mulga snakes) R. Others II. Viperidae ......... ................. ...................... 10 A. Adenorhinos (worm-eating vipers) B. Atheris (bush vipers) ix x Toxicology & Plwrmacology of Venoms from Poisonow Snoke& C. Atractaspis (burrowing or mole vipers) D. Azemiops (Fea's viper) E. Bitis (puff adders) F. Causus (night adders) C. Cerastes (homed vipers) H. Echis (carpet or saw-scaled vipers ) I. Eristocophis (Asian sand vipers) J. Pseudocerastes (homed desert vipers) K. Vipera (European and related tree vipers) III. Crotalidae ................................................................................... 13 A. Agkistrodon (copperheads, cottonmouths, etc.) B. Bothrops (lance-headed vipers) C. Crotalus and Sistrurus (rattlesnakes) D. Lachesis (bushmaster) E. Trimeresurus (Asian pit vipers) IV. Hydrophidae (sea snakes) ....... ....................... 16 V. Colubridae ............................... ....................... 17 A. Dispholidus (boomslang) B. Thelotornis (bird snake) Table I Poisonous Snakes of North America ................................... 18 Table II Poisonous Snakes of Mexico, Central and South ................ 23 America Table III Poisonous Snakes of Africa .................................................. 39 Table IV Poisonous Snakes of Europe ........................................ 48 Table V Poisonous Snakes of the Near East ........................................ 50 Table VI Poisonous Snakes of India, Southeast Asia and the Indonesia Area .......................................................................... g Contents xi Table VII Poisonous Snakes of Australia, New Guinea and Pacific Islands """',......... .................... 64 CHAPTER 2 TOXICITY AND VARIATION IN YIELDS OF VENOM FROM POISONOUS SNAKES ,., ........ ,.................................. 74 I. Toxicity in mice .......... ,.. ..... ,., .................... 74 A. Intravenous toxicity B. Intraperitoneal toxicity C. Subcutaneous toxicity Table VIII Toxicity of Snake Venoms in Mice in Mg/kg"........ .. 77 II. Toxicity in dogs and rabbits ... ,.... ,., ................................ , .. 84 Table IX Toxicity of Snake Venoms in Dogs in Mg/kg .... , .............. 84 Table X TOxicity of Snake Venoms in Rabbits in Mg/kg .... ' ... ,.... 85 III. Routes of administration .......................................................... 85 Table XI Ratios of Snake Venom Toxicities in Various Species ........ 86 IV. Variation in amounts of venom .. ' ........................................... 87 A. Age of the snake Table XII Protein and Solid Content of Venoms, ." .... ".88 B. General status of health C. Prandial state D. Effect of repeated milking E. Effect of sex F. Effect of temperature G. Average yields of various venoms Table XIII Quantity of Dried Venoms Extracted from Poisonous Snakes .... ,.... ,."' ....................................................................... 91 xii Toxicology & Pharmacology of Venoms from Poisonous Snakes V. Discussion and estimated human toxicity data .... ... ......... 95 Table XIV Estimated Number of Lethal Doses for Humans.. ....... 96 CHAPTER 3 PHARMACOLOGY OF SNAKE VENOMS ... 99 I. Cardiovascular effects .... ... 99 A. Timber rattler (C. horridus ) B. Easte rn and Western diamondback (C. adamanteus and C. atrox) C. Cottonmouth mocassin (A. piscivorus) D. Northern copperhead (A. contortrix mokeson) E. Southern copperhead (A. cOlltortrix contortrix) F. Indian krait (B. caeruletls) C. Coral snake (M. fulmus) H. Russell's viper (V. russellii) I. Puff adder (B. lachesis) J. Indian cobra (N. naia) l. Separated components a. Isolated neurotoxins b. Cardiotoxin c. Purified phospholipase A 2. Isolated tissue studies a. Action on phrenic nerve-diaphragm b. Chick biventer cervicis muscle c. Frog l1wtor nerve-Sartorius muscle d. Frog rectus abdon-Lillis muscle K. Sea snake (Laticauda laticauda ) 1. Isolated tissue studies a. Isolated frog heart b. Isolated rabbit heart c. Blood vessels of the frogs hind limb d. Blood vessels of the rabbit's ear e. Isolated rabbit ileum f. Isolated rabbit uterus Contents·· xiii g. Frog sciatic-gastrocnemius h. Analgesic activity 2. Isolated sea snake toxins L. Walterinnesia aegyptia toxin II. Histamine ." ...... "....... ................ .115 III. Slow reactingiUb8tance . ............... ..117 IV. Bradykinin ........................................................ .... 120 V. Effects of venom on nerve transmission. .......... ..: .... 125 VI. Absorption and dMribution ............................................. 128 A. Bungarus multicinctus venom B. Naja naia atra venom VII. Hemorrhagic activity .131 CHAPTER 4 CAPTURING, HOUSING AND EXTRACTING POISONOUS SNAKES.. ......... ....... 132 I. Venom extraction .. .132 II. Hunting for rattlesnakes. ..134 III. Housing poisonous snakes .....................