So I've Been Bitten By a Cobra - Now What?

[carl_johnson]

Had a strange conversation with someone tonight who telling me about a gentleman who extracted cobra venom in order to somehow prepare an antivenom for emergencies…obviously this seems counter-intuitive so perhaps someone can shed some light on what cobra antivenom is generally made with and if there is any logical reason that someone would extract venom in order to somehow treat a future bite?

[Q.E.D]

Antivenin is produced in general by administering small doses of the target snake venom to an animal, such as a chicken, which causes the animal to produce antibodies specific to that particular venom. These antibodies can be extracted in any of several ways and refined to produce the final anitivenin product. Once such process is discussed here.

[Cisco]

@Q.E.D.

Antivenin is produced in general by administering small doses of the target snake venom to an animal, such as a chicken, which causes the animal to produce antibodies specific to that particular venom.

I was under the impression that horses were usually used, being mammalian and all, and then what with anything being deadly to a human would likely kill a chicken even faster, leaving it little time to produce antibodies. I may be wrong though; I’m off to look into it.

[hlanelee]

Blood serum from people that have been bitten and survived is an antivenin. People that make their living handling venomous snakes are often injected with snake venom to build immunity. Dad was bitten by several North American vipers and survived. He said that each time it happen recovery was quicker and easier. He also noted that he had strange dreams on nights when he was snakebit.

[ouryL]

Bite me? This little thing?

[Ilsa_Lund]

Note: In the United States, the standard for many years was Wyeth Polyvalent antivenin, produced from equine antibodies. The standard is now CroFab Polyvalent antivenin, of ovine origin.

[Q.E.D]

@Cisco

I was under the impression that horses were usually used, being mammalian and all, and then what with anything being deadly to a human would likely kill a chicken even faster, leaving it little time to produce antibodies. I may be wrong though; I’m off to look into it.

I mentioned chickens only because the link I gave discusses a new method of pruducing antivenins from the eggs of innoculated chickens. True enought that most antivenins currently used are derived from horses.

[Ilsa_Lund]

@Q.E.D.

I mentioned chickens only because the link I gave discusses a new method of pruducing antivenins from the eggs of innoculated chickens. True enought that most antivenins currently used are derived from horses.

Sheep, in the States.

[carl_johnson]

neat stuff…slick hijack:

Are the terms ‘Antivenin’ and ‘Antivenom’ interchangable? Whats the difference?

[cichlidiot]

@Cisco

I was under the impression that horses were usually used, being mammalian and all, and then what with anything being deadly to a human would likely kill a chicken even faster, leaving it little time to produce antibodies. I may be wrong though; I’m off to look into it.

I think you’re both right, if you change chicken to pigeon. From *Venomous Reptiles, Sherman A. Minton, Jr. Charles Scribner’s Sons, 1969 * p.94 -

The first successful scientific attempt to immunize an animal against snake venom was reported in 1887 by Henry Sewall, a young professor of physiology at the University of Michigan. He used venom from the massasauga, still occasionally found near Ann Arbor. After determining that pigeons died after injection of 2/5 drop of glycerin-diluted venom but survived a dose of 1/5 drop, he injected a group of pigeons with gradually increasing doses. About 6 months later, one of these pigeons survived a dose of 3 drops of glycerin-venom mixture and another withstood 4 drops. Sewall’s experiment not only showed that immunization against snake venom was possible; it was the cornerstone of all antitoxin therapy.

From page 95 -

The first antitoxic serum for snakebite treatment was produced in 1895 at the Pasteur Institute in Paris under the direction of the French bacteriologist Albert Calmette (1863-1933) from the serum of horses immunized against cobra venom. The preliminary work was done by two French scientists, Cesaire Phisalix and Gabriel Bertrand working at that time (1893-94) at the Museum of Natural History in Paris and by Fraser in Edinburgh. It was Fraser who coined the name “antivenene” for this type of antitoxic serum; the spelling “antivenin” is usually used in America.

As far as recovery being quicker and easier after successive bites, though I’m sure more research has been done by now, from page 92 -

In a Florida study, fourteen biologists , animal dealers, snake handlers, and herpetologists who had been bitten 2 to 12 times apiece by poisonous snakes were interviewed in detail. Nearly all their bites were inflicted by North American pit vipers and ranged in severity from mild to almost fatal. There was no evidence that the repeated bites conferred any immunity. For one subject, his tenth and fifth rattlesnake bite was the most serious one he sustained[…]Serum samples from these persons did not neutralize the effects of rattlesnake venom on animals. The unpredictable amount of venom injected in a natural bite and the long and irregular intervals between bites were thought to be the main reason for failure of immunity to develop in these persons.

Since the amount of venom injected is so variable, I’d rather not rely on past bites as insurance. The book estimates a rattlesnake (timber) bite does not involve injection of venom in nearly 20% of the cases, so it made me wonder how often a person really gets a full injection. I bought the book, because I was interested in getting a Gaboon Viper (Bitis Gabonica) and talked to a friend who keeps “hot” snakes. He recommended starting out with something less agressive since he’s against owning venomoid snakes. After reading this book and a few others, and some information about venomoid snakes as well, I decided that no venomous snake is really safe, and I’m better off looking from a distance.

One part I found interesting, from page 93, talks about an Australian herpetologist,

…who received 24 injections of tiger snake venom during a period of slightly more than a year. Before he began immunization he had been bitten 9 times by Australian poisonous snakes[…] His first injection was 0.002 milligram of venom; this was increased to 25 milligrams (an estimated 8 to 16 times the lethal dose) by the twenty-fourth dose[…] When he began immunization his blood contained 0.2 unit of tiger-snake antitoxin per milliliter, evidently the result of earlier bites. Two months after immunization, his antitoxin level had risen to 5.2 units per milliliter, probably enough to neutralize the bite of any tiger snake, but a year later it had fallen to 0.5 unit.[…] A little more than a year after his last immunizing injection he was bitten on the hand by a 3 foot tiger snake. He had no symptoms of poisoning other than the slight swelling of the bitten hand. The level of antitoxin in his blood rose sevenfold soon after the bite. This was interpreted as an anamnestic or recall response indicating he received an appreciable dose of venom.

The book goes on about experiments in horses and mice, and booster injections of antivenin. One last paragraph on p. 97 seems pertinent to this discussion,

Antivenins may be produced against venom of a single species of snake (monovalent) or against a mixture of venoms (polyvalent). Luckily it is not necessary to produce a separate antivenin for each species of snake. Tiger-snake antivenin not only neutralizes venoms of most Australian snakes but also is at least moderately effective in neutralizing cobra, krait, ringhals, black-mamba, desert-blacksnake, and sea-snake venoms. An antivenin that neutralizes venoms of most New World pit vipers has been produced by using a mixture of three rattlesnake and one Bothrops venoms. One of the challenges in antivenin research is finding combinations of venoms that will give the broadest spectrum of protective antibodies.

[Derleth]

@carl_johnson

neat stuff…slick hijack:

Are the terms ‘Antivenin’ and ‘Antivenom’ interchangable? Whats the difference?

CancerWEB’s dictionary

antivenin

An antitoxin specific for an animal or insect venom.

Synonym: antivenene

ditto

antivenom

<pharmacology> A medication that contains an antibody, specific to a toxin, for the purpose of deactivating its harmful effect.

So, it seems that antivenins are specific to animal and insect toxins, as opposed to antivenoms which might work against, say, plant or artificial toxins.

[USCDiver]

@Ilsa_Lund

Note: In the United States, the standard for many years was Wyeth Polyvalent antivenin, produced from equine antibodies. The standard is now CroFab Polyvalent antivenin, of ovine origin.

Note that CroFab does not work for Coral Snake bites or for non-native species. There was a fellow in Greenville, SC a couple of years ago who was bitten by his pet cobra :rolleyes: while posing for pictures with it :rolleyes: :rolleyes: They hunted around and finally found some cobra antivenin at a zoo in Miami. Instead of flying the expensive antivenin to SC they flew the patient to Miami.

[Ilsa_Lund]

@USCDiver

Note that CroFab does not work for Coral Snake bites or for non-native species. There was a fellow in Greenville, SC a couple of years ago who was bitten by his pet cobra :rolleyes: while posing for pictures with it :rolleyes: :rolleyes: They hunted around and finally found some cobra antivenin at a zoo in Miami. Instead of flying the expensive antivenin to SC they flew the patient to Miami.

It isn’t the non-native part, it’s the non-crotalid part. The name “CroFab” kinda gives it away. It is a broad-spectrum antivenin designed to combat the most common hemmorhagic and hemotoxic components of crotalid venom. It has limited efficacy with almost all north American crotalid species, but elapid-specific antivenins are required in the case of elapid bites.

CroFab