Australian Snakes Relative Toxicity
Relative Toxicity in Snake Venoms
Peter Mirtschin, Venom Supplies Pty Ltd
PO Box 547 Tanunda South Australia 5352
Phone 61 85 63 0001, Fax 61 85 63 0020
Email venomsup@dove.net.au
Home page http://dove.net.au/~venomsup
Snake venoms are complex mixture of many different toxins which the snake uses for capturing and digesting prey.
Medical emergencies are created when humans are envenomated. Most venoms are different but many have common toxins.
Most venoms contain either neurotoxins, hemorrhagic toxins or both. In the past toxicity was measured by injecting test animals (mainly mice) with venom; however, many different types of animals have been used.
Mice were the universally accepted test animal and comparative toxicity was expressed as an D50 lethal dose that kills 50% of test animals).
The LD50 is usually determined by injecting the crude venom (by various routes) into mice at varying concentrations.
Today, these types of experiments are not generally performed because of animal welfare concerns, however they have been valuable in understanding the toxicity of both crude venoms and purified single toxins.
There are other specific tests that look at the effect
of single toxins. These can be clotting assays to measure the effect
of coagulants, nerve-muscle preparations to measure neurotoxic activity,
phospholipase and phosphodiesterase assays which measure these respective
agents in the venoms. Even muscle or myoblast preparations to measure
the myotoxic activity of venoms have been used. These tests are useful
to investigate the relative toxicity of purified toxins but there is
sometimes a poor correlation between these results and the in vivo effects
of the venom or toxin.
The Commonwealth Serum Laboratories in Australia in 1979
compared the toxicity of most of the Australian medically important
snake venoms and few venoms from non-Australian snakes. Mice were subcutaneously
injected with the crude venoms. Table 1 is a listing of snake in the
order of their toxicity. The order of toxicity is based upon the cobra
scale which has a number of one and the other snake venoms are compared
to the Indian cobra (Naja naja naja).
Australian Snakes Relative Toxicity
Table 1: The relative toxicity of venoms using
Indidan cobra (Naja naja naja) as the standard with a value of 1.
| Common Name(Australian) | Scientific Name | Relative Toxicity |
| Inland taipan | Oxyuranus microlepidotus | 50.0 |
| Common brown snake | Pseudonaja textilis | 12.5 |
| Taipan | Oxyuranus scutellatus | 7.8 |
| Reevesby Is. tiger snake | Notechis ater niger | 5.1 |
| Common tiger snake | Notechis scutatus | 4.2 |
| Western tiger snake | Notechis ater occidentalis | 4.0 |
| Beaked sea snake | Enhydrina schistosa | 2.9 |
| Chappell Is. tiger snake | Notechis ater serventyi | 1.8 |
| Common death adder | Acanthophis antarcticus | 1.5 |
| Western brown snake | Pseudonaja nuchalis | 1.5 |
| Copperhead | Austrelaps superbus | 1.0 |
| Dugite | Pseudonaja affinis | 0.9 |
| Stephens banded snake | Hoplocephalus stephensi | 0.4 |
| Rough scaled snake | Tropidechis carinatus | 0.5 |
| Spotted black snake | Pseudechis guttatus | 0.3 |
| King brown snake | Pseudechis australis | 0.3 |
| Collets snake | Pseudechis colletti | 0.2 |
| Red bellied black snake | Pseudechis porphyriacus | 0.2 |
| Small-eyed snake | Cryptophis nigrescens | 0.2 |
| Whip snake | Demansia olivacea | <0.1 |
| Common name | Non-Australian Scientific Name | Relative Toxicity |
| Indian cobra | Naja naja naja | 1.0 |
| Papuan black snake | Pseudechis pauanus | 0.4 |
| King cobra | Ophiophagus hannah | 0.3 |
| E. diamondback rattlesnake | Crotalus adamanteus | <<0.1 |
| Brazillian viper | Bothrops atrox | <<0.1 |
References
1. Sutherland,S.K. (1983). Australian Animal Toxins. Oxford University
Press. Melbourne. p54.
2. Francis, B., John, T.R., Seebart, C. and Kaiser, I.I. (1996). New
toxins from the venom of the common Tiger Snake (Notechis scuatatus
scutatus). Toxicon 29(1) 85- 96.
3. Francis, B., Williams, E. S., Seebart, C., Kaiser, I. I. (1993).
Proteins isolated from the venom of the common Tiger Snake ( Notechis
scutatus scutatus ) promote hypotension and hemorrhage. Toxicon 31(4).
447-458.
4. Tans, G., Govers-Rienslag, J.W.P., van Rijn, J.M.L. and Rosing, J.
(1985). Purification and properties of a prothrombin activator from
the venom of Notechis scutatus scutatus.The Journal of Biological Chem.
260(16). 9366-9372.
5. Jobin, F. and Esnouf, M.P. (1966). Coagulant activity of Tiger Snake
(Notechis scutatus scutatus) venom. Nature 211(5051). 873-875.
6. Picciuto, R., Marshall, L.R.(1994). Unique anticoagulant activity
of Tiger Snake venoms (Notechis species). In press
7. Minton, S and Minton, M.R. (1969). Venomous Reptiles. Scribners New
York.
8. Nahas, L., Denson, K.W.E. and Macfarlane, R.G. (1964). A study of
the coagulant action of eight snake venoms. Thromb. Diath. Treat. 12
355-367.
9. Thesleff, S. (1979). Reptile toxins and neurotransmitter release.
Eds. I.W. Chubb and L.B. Geffen. Neurotoxins. Fundamental & Clinical
Advances. Centre for Neurosciences. Flinders University. 19-25
10. Broad, A. J., Sutherland, S. K., Coulter, A.R. (1979). The lethality
in mice of dangerous Australian and other snake venoms. Toxicon (17).
664-667.
11. Mirtschin,P.J. and Davis,R. (1982). Dangerous Snakes of Australia.
Rigby. Adelaide.
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