Chapter 



HOW TO RECOGNIZE SNAKE VENOM POISONING 

 Symptoms and Signs 



INTRODUCTION 



In most parts of tlu' world, liili's hy ikiiinciio- 

 inoxis siiiikes occur fai- inori" rriMiuciitly lliuii liitcs 

 hy venomous siiakos. Since the ditlei-ential ion is 

 often ditlicult. all \ictiins of snakebite sliould he 

 brought under the care of a physician as quickly 

 as possible. Whenever feasible the ofTendinji 

 snake should be killed and broufjht with the vic- 

 tim to the physician or person chartjed with the 

 responsibility of identifying the reptile. 



While it is not always possible to identify the 

 snake responsible for the bite by the tooth or fang 

 marks found on the victim's skin, in some cases 

 these may be of considerable value in diiferentiat- 

 ing between bites by venomous and nonvonomons 

 species. Bites by the vipers (Old World vipers, 

 pit vipers of Asia, eastern Eurojie, and the rattle- 

 snakes and related species of the Americas) 

 usually result in one or two relatively large jiunc- 

 ture woiuuls of varying depth, depending on the 

 size of the snake, the force of its strike, and other 

 factors. In most cases, additional tooth marks 

 are not seen. Bites by the elapid snakes (cobras, 

 mambas, tiger snake, taipan, coral snakes and 

 related species) usually produce one or two small 

 puncture wounds, although occasionally there 

 ma}' be one or two additional punctures. Sea 

 snake bites are characterized by multiple (2 to 

 20) pinhead-sized puncture wounds. In some 

 cases the teeth may be broken off and remain in 

 the wound. 



Proper identification of fang or tooth marks 

 may be complicated in those cases where skin 

 tears result from jerking an extremity away dur- 

 ing the biting act. This is a particular problem 

 in viper bites where long scratches or even lacera- 



I ions ai-f inllidcd liy the fangs. In biles by 

 elapid snakes there may be superficial scratches 

 from the snake's mandibular and palatine teeth. 

 Thus, it can be seen that while fang or tooth pat- 

 lerns may be of assistance in determining the 

 identity of an offending snake, they should not be 

 dejiended upon as tlie deciding factor in estab- 

 lishing the diagnosis. 



It should be noted that (inr cnii he li'/ttcii Iji/ ii 

 riuioDioiis sniiki mill not Ik jio'ixoiud . In IS to 

 40 ])er cent of the bites inflicted by venonu)us 

 snakes, no signs or symptoms of poisoning 

 develop. This may be due to the fact that the 

 snake does not always eject venom or, if venom is 

 ejected, that it does not enter the wound, as can 

 sometimes happen in very superficial bites. 

 This important fact should always be considered 

 before s])e<-ific treatment is started. 



Venom Apparatus 



The venom apparatus of a snake consists of a 

 gland, a duct, and one oi- moi'e fangs located 

 on each side the tlie head (fig. 1). The size of 

 these structures depends on the size and spe- 

 cies of the snake. Each venom gland is in- 

 vested in a connective tissue sheath which is in- 

 vaded by the muscles that contract it during dis- 

 charge of the venom. The innervation of these 

 muscles is different from that controlling the 

 biting mechanisms; thus, the snake can control 

 the amount of venom it ejects. It can discharge 

 venom from either fang, from both, or from 

 neither. Snakes rarely eject the full contents of 

 their glands. 



Most rattlesnakes probably discharge between 

 25 and 75 percent of their venom when they bite 



