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Venom Chart
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by JTEDENS on May 7, 2003
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The venom chart on this site has some species listed as 'local/systemic effects' under the Lethal Dose category. What exactly does this mean? Is the Lethal Dose the LD50? Is local/systemic to mean that human fatalities have not occurred? Furthermore C. tigris and C. willardi are listed as local reactions. Is this to mean that a bite from them would be painful but not life threatening in any way? Will the chart be expanded to include all North American species? Will it include specimens from other countries?
Thanks for any responses, John
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RE: Venom Chart
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by Rabies on May 7, 2003
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Hi John
when discusing the efects of an envenomation the signs and symptoms will generaly be put into 2 category's ie Local=around the bite site:- fang puncture marks,disscolouration,swelling,bleeding from fang punture etc.Systemic=the rest of the body,which depending on what type of snake:-blood clotting disorders,bleeding internaly or from your gums,drooping eyelids,difficulty in swallowing etc.
The LD50 is exactly what you said,50=50%,so a certain amount of venom has been calculated that when injected into an animal(normaly mice)the half will die.It does not necessary compute to humans but it gives a general idea on how toxic they are.As for the C.tigris its LD is on par with the Mojave and depending what litreture you read some put it as N Americas most venomous Rattler.But I'm not aware of the tiger causing any fatalities,but the mojave has.
Hope this helps some.
regards
John
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RE: Venom Chart
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by Rabies on May 7, 2003
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My mistake,the LD on this chart is the estimated dose required to kill an average human being.
john
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RE: Venom Chart
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by JTEDENS on May 8, 2003
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Thanks for the reply. What about the Gila? Normal yield is listed in ml but lethal dose is in mg. What is the concentration of the venom? Also, to my knowledge no one has ever died from a Gila bite, if that is the case is the lethal dose an estimate of what it would take to kill a person? I know a few people that have been bitten by juvenile Gilas, with extreme pain but no medical attention. I don't know all the details of the bites, but I would assume that the Gila didn't hang on for very long. C. tigris, willardi, and pricei seem to have a very small venom yield. Is that to say that their venom is actually stronger than some other species of Crotalus, but due to the small yield bites are usually not life threatening?
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RE: Venom Chart
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by Rabies on May 8, 2003
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Hi,as I have already mentioned LD for humans are estimates only,as experiments are not performed on human's.(GILA)The LD in mice IntraVenously(IV)is in the range of 0.4 to2.7 mg/kg.The average yield is 17mg,(Findlay Russel)Pain is one of the major compalints and depending how much venom is delivered depends how quickly,painfull,and how far up the limb the pain goes,also nausea sweating and feeling faint have been recorded.As far as I can find there has'nt been any substaniated reports on fatalities.The Tigris LD is simular to that of a mojave(can't find it)but its only a small snake with an exceptionly small head.As for the other 2 I don't honestly know!Like you said bites are usually not life threatening,but dont take that as gospel!you could aleays become the first.Ask BGF for a more up to date info on LD of the smaller sp Crotalus.
John
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RE: Venom Chart
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by JTEDENS on May 8, 2003
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I found the LD50's on BGF's site for the Crotalus species. My question about the Gila was because you stated that the lethal dose on the chart was for the average human. Apparently Tiger rattlers are even more lethal than black mambas, tigris being 17th and polylepis being 23rd, scutulatas ranks 26th. This info is from BGF's website and info is from LD50 subcutaneous. I appreciate your help and your explanation of the chart used on this site.
Thanks, John
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