Elapidae

The similarity of the primary structure of different sea snake venoms has already been discussed. Postsynaptic neurotoxins from Elapidae venom have been extensively studied. Elapidae include well-known snakes such as cobra, krait, mambas, coral snakes, and all Australian snakes. Like sea snake toxins, Elapidae toxins can also be grouped into short-chain (Type I) and long-chain (Type II) toxins. Moreover, two types of neurotoxins are also similar to cardiotoxins, especially in the positions of disulfide bonds. However, amino acid sequences between cardiotoxins and sea snake and Elapidae neurotoxins are quite different. In comparing the sequence of sea snake and Elapidae neurotoxins, there is a considerable conservation in amino acid sequence, but the difference is greater than among the various sea snake toxins. 

Similarity of venoms among different sea snakes and Elapidae can also be detected immunologically. For instance, the antibody for Enhydrina schistosa showed cross reactivity with the venoms of Hydrophis cyanocinctus, Lapemis hardwickii, and Pelamis platurus 12). The sea snake antivenin not only neutralizes the toxicity of various sea snake venoms, but also Naja naja atra (Taiwan cobra) venom 13-16). The reverse is also true namely, some Elapidae antivenins are also effective for neutralizing sea snake venom lethality 17-19). 

The second most common venomous snakes are the Elapidae, of which cobras and coral snakes are well known. These snakes deliver their venom from fixed fangs and must hold onto the victim while the venom is released. These snakes tend to... 

Elapidae Cobras Kraits Coral snakes Neurotoxin (some very potent) Fixed fangs, usually low dose Nervous system effects, paralysis, numbness, respiratory failure... 

The clinical features depend upon the type of snake bite. There are three main patterns neurotoxic, as with elapidae such as cobras and kraits vasculotoxic with alteration in blood coagulation as with vipers and myotoxic as with sea snakes although they are all often complicated by local tissue damage. The severity of poisoning will depend on the amount and potency of venom injected and the patient s general health. 

Presynaptic snake neurotoxins endowed with PLA2 activity (SPANs) are major components of the venom of four families of venomous snakes (Crotalidae, Elapidae, Hydrophiidae, and Viperidae). These neurotoxins play a crucial role in envenomation of the prey (Harris 1997) by causing a persistent blockade of neurotransmitter release from nerve terminals with a peripheral paralysis very similar to that of botulism (Connolly et al. 1995 Gutidrrez et al. 2006 Kularatne 2002 Prasampun et al. 2005 Theakston et al. 1990 Trevett et al. 1995 Warrell et al. 1983). 

Bungarotoxin] [From Elapidae snake Bungarus Presynaptic NM ACh... 

Fasciculins characterized From the mamha snake venoms (Elapidae family) Dendroaspis genus)... 

Clinically, mamba bites may not provoke a major local reaction. If neurotoxins are injected by the bite, clinical symptoms appear within minutes to hours. Clinical signs of impairment of neuromuscular transmission (ptosis, ophthalmoplegia, bulbar symptoms, or generalized weakness) dictate administration of antivenom (Ludolfph, 2000). For Elapidae (coral snakes) venom is known that is a potential neurotoxin and may cause paresthesias, weakness, cranial nerve dysfunction, confusion, fasciculations, and lethargy. Often mild local findings, diplopia, ptosis, and dysarthria are common early symptoms. Patients die because of respiratory paralysis. In these cases, early and aggressive... 

Snakes belong to the phylum Chordata, Class Rept-ilia. Two major families of venomous snakes are Crotalidae and Elapidae. 

This family includes coral snakes, cobras, mambas, and kraits. In the United States, Elapidae are responsible for 1-2% of poisonous snakebites. The incidence of envenomations is greater in some other parts of the world. Examples of coral snakes commonly found in the United States are the eastern coral snake, the Sonoran coral snake, and the Texas coral snake. Coral snakes are smaller than pit vipers. They do not have facial pits, and the head is rounded, as are the pupils. Eangs are 2mm and fixed to the jaw. Coral snakes are also more brightly colored, with bands of black and red, separated by yellow and white bands. Coral snakes are timid, nocturnal creatures. 

See also Animals, Poisonous and Venomous Snake, Elapidae Snakes. 

Systemic absorption of Elapidae venom is dependent on lymphatic transport following subcutaneous envenomation. The onset of neurotoxic symptoms usually occurs within 4h but can be delayed up to 10 h following a bite. The metabolism of venom components is not well understood. It is likely that venom components are inactivated by enzymes within tissues where the venom is ultimately distributed. The distribution of venom is variable and complex and possibly reaches different tissue sites unevenly. The biological half-life of Elapidae venom has not been determined. It is likely that metabolized venom fractions are eliminated primarily by the kidneys. 

Elapidae venom is composed of different components that vary among species. The venom of North American species contains fractions that are primarily neurotoxic. The venom results in a bulbar-type cranial nerve paralysis. In contrast to Crotalinae species, venom from North American elapids lacks most of the enzymes and spreading factors that cause local tissue destruction. Elapids from countries other than the United States can contain venom components different than that of North American coral snakes. 

Coelho LK, Silva E, and Espositto C (1992) Clinical features and treatment of elapidae bites Report of three cases. Human Experimental Toxicology 11 135-137. 

All venomous snake species occur within the superfamily Colubroidea advanced snakes , a large and ecologically diverse group distributed worldwide. Within Colubroidea there are five families that have species (all or in part), which are considered venomous Elapidae, Viperidae, Hydrophiidae, At-ractaspididae, and Colubridae. 

Eastern coral snake, Micrurus lulvius Elapidae 1.30... 

Snake, Elapidae, Pages 56-57, Gary W. Everson SummaryPlus Full Text + Links PDF (52 K)... 

Finally, venoms from different snakes from the Elapidae and Hydrophidae families also contain a cocktail of different paralytic toxins, some of which are selective for voltage-dependent Ca channels. For instance, the venom of the black mamba Dendroaspis polylepis polylepis contains a toxin termed calciseptine, which selectively blocks L-type Ca channels [6] and the venom from the green mamba D. agusticeps contains calcicludine, a toxin that acts as a potent blocker of most of the HVA Ca channels [7]. 

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