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Tarantula venom causes paralysis in humans?

Discussion in 'Tarantula Questions & Discussions' started by dragonblade71, Sep 6, 2007.

  1. dragonblade71

    dragonblade71 Arachnobaron

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    I was reading a website which described possible symptoms that one could obtain from a tarantula bite and one of these was paralysis! The website does state that this would be temporary. Other symptoms mentioned were myonecrosis and 'localised death of muscle cell fibres.' I have read various sources which mention symptoms that would likely result from tarantula bites though I have never come across these particular symptoms described before. I must say that these symptoms sound quite severe.

    I am planning to obtain an Australian tarantula which are usually known to inflict the worst symptoms of any tarantula bite. If I am unlucky to get bitten oneday, I am hoping that I won't experience any of the symptoms mentioned above (but I do expect that I'll have to put up with the usual pain and swelling and possible nausea.) Can any of the knowledgeable board members here confirm whether the symptoms described from the website are really plausible in regards to tarantula bites?

    This is the site below which describes the possible effects of bites.

    http://www.tarantulatour.com/thebite.html
     
  2. Rochelle

    Rochelle Arachnoprince

    I'm told that Pterinocilous murinas will cause muscle tremors; so the especially nasty Australian T's would seem to be the best candidate for temporary muscle paralysis. Logical conclusion. Maybe you'll get lucky and one of the REAL experts will be able to answer your Q. It's a good one, considering that more of these "wonderful nasties" are being shipped and sold here..... The answer will benefit us all.
     
  3. DrAce

    DrAce Arachnoangel

    The magic words in that website are all there "Could" and "might".
    For clarification, myonecrosis IS death of muscle fibers, localized or otherwise. Myo means muscle, and necrosis means death.

    I think you're better to look for actual reports from the species you are interested in. There is a great resource here on the boards - the bite section, and, to my knowledge, no-one has reported myonecrosis.

    The site is right, however, the real danger comes if you are alergic. I doubt myonecrosis would result, but you may stop breathing -and that does lead to myonecrosis!

    There are spiders which will cause necrosis -the recluse and the hobo are amongst them (although some argue that this is a consequence of secondary infection, not the bite).

    I am of the understanding that most tarantula bites are immune responses more than anything else - something an anti-histamine will take care of. The Australian Funnel Web, however, will also cause necrosis followed quickly by death.

    All data from "Color atlas of human poisoning and envenoming" by James Diaz, CRC Press, 2006: ISBN 0-8493-2215-4
     
  4. Moltar

    Moltar ArachnoGod

    Take some time to browse the bite reports. They can be pretty entertaining in a sadistic sort of way. The "paralysis" actually experienced w/ P murinus were more like tremors, bad muscle aches, spasms, etc. The scariest one i saw was labored breathing like someone was pressing down on their chest. Presumably from partial paralysis of the diaphragm muscle. Eeeks!
     
  5. Scott C.

    Scott C. Arachnofloater Arachnosupporter

    Hey Doc,
    I was under the impression that alergic reactions to T venom don't happen due to size of proteins/peptides, or some such scientific jargon...

    Has that changed, or was it wrong to begin with?
     
  6. Crotalus

    Crotalus Arachnoking Old Timer

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    No you were right.
     
  7. dragonblade71

    dragonblade71 Arachnobaron

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    "I think you're better to look for actual reports from the species you are interested in."

    Yea I have previously read the bite reports on the board for two cases of Australian tarantula bites. In one of these cases, the victim suffered some loss of vision which is a symptom that i have certainly never heard of before! The same person also reported that they lost sense of where they were after the bite occurred.
     
  8. Crotalus

    Crotalus Arachnoking Old Timer

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    You cannot suffer severe allergic reaction due to the venom components that in spider venom are very different from for example snake or bee venom (that readily cause anaphylaxis)
    This is not my words but toxinologist Bryan G Fry.

    See above.
    The funnel web venom are neurotoxic with no local necrosis (in Atrax envenomations) - perhaps species in Hadronyche cause local necrosis but its the least of worries if bitten by one.
     
  9. Moltar

    Moltar ArachnoGod


    Yeeeowch!!! that's pretty hardcore.

    Yaknow... there are people on here that keep deathstalker scorps, rattlesnakes, vipers, widows, etc. Those guys have balls. Big solid steel bulletproof balls that i apparently do not (ladies please apply your organ of choice in place of the afore mentioned balls) Maybe it's because of my little nephews always visiting and maybe it's because i'm just plain scared but i don't want any critters in my house that could potentially kill or permanently disable or disfigure someone. Nothing against those of you that do of course. I guess y'all are just more confident in your husbandry skills or whatever. Hat's off to ya!

    I'll stick w/ my fair-to-middlin toxicity bugs, thank you.
     
  10. Rochelle

    Rochelle Arachnoprince

    Bosh! Come to a Detroit rock concert. All the same symptoms can be experienced - without a Tarantula in sight....lololol PARKING - now THAT'S deadly! ;P
     
  11. Venom

    Venom Arachnoprince Old Timer

    Whatever report you read, it was way overblown.

    Tarantula venom will not cause significant necrosis, or even Cheiracanthium-level necrosis, no matter what the species. They simply lack the cytotoxic or hemolytic components to make this happen. The only way a tarantula bite *MIGHT* cause ANY notable tissue death is if swelling occurred to the extent that it cut off circulation. I am aware of one case that almost had an amputation for Poec-induced swelling, but this was more a case of incompetent doctors than a good treatment option. Severe swelling can result from Poecilotheria, Pterinochilus, and a few other genera, but the number of cases causing circulation-stopping swelling would be measured in thousandths of a percentile.

    As for paralysis, not likely. The only systemic paralysis case I know of was from P.striata, and it wasn't true paralysis. What happened was that, whenever the subject tried to move, all his muscles cramped and seized up--making him, practically speaking, unable to get off his bed. However, he was technically still was able to engage his muscles. As for local paralysis/ stiffness --yeah, ok. Sometimes people nailed by a pokie can't use their hand for a while. But I get about the same whenever I slam a finger/hand in a car door or hit it with a hammer.

    Australian tarantulas are among the more potent T's, but that isn't saying much as far as toxic inverts go. There are no deaths, and you won't be paralyzed. What you might get from a strong ( above average ) bite, could include dizziness, muscle cramping, confusion, pain, nausea--that sort of thing. As always, it's a question of what you feel comfortable dealing with. If you feel you can keep yourself safe, and the risk is acceptable, then go for it. If not, there are loads of other species out there! Just keep what you can safely enjoy.


    If you're up for that, you're probably ready for an Aussie. Just treat them with the respect you'd give a pokie.
     
  12. Scott C.

    Scott C. Arachnofloater Arachnosupporter

  13. DrAce

    DrAce Arachnoangel

    With all due respect, Crotalus, I beg to differ. From Bryan G. Fry's own website:

    "Spider venom peptides
    Mu-Agatoxins
    The nomenclature of spider peptidic neurotoxins is, unlike that of scorpions, based on the same convention as that of cone-snails and snakes: alpha-toxins inhibit the acetylcholine receptor; mu-toxins directly abolish muscle action potentials through the inhibition of muscle sodium channels; and omega-toxins prevent voltage-activated entry of calcium into the nerve terminal and the release of acetylcholine.

    Spider mu-toxins are cysteine-rich polypeptides, which cause irreversible paralysis and repetitive action potentials originating in presynaptic axons or nerve terminals. Clinical effects of a bite from one of the North American funnel web-spider Agelenopsis aperta are negligible. The venom, however, has yielded several interesting peptides that have pharmacological properties that may prove to be quite useful. Two specific mu-agatoxins have been identified from A. aperta, mu-agatoxin-I and mu-agatoxin-IV, both of which contain 36 amino acids and four internal disulfide bonds. Although these toxins specifically modify voltage-sensitive sodium channel activity, they have structural similarities with a plethora of other peptide toxins targeting a myriad of channel types. Analysis of these variations may shed light not just on functional residues of the particular scaffold but also provide data as to the structure and specificity of the binding sites of the channel being affected. This adds to the emerging wealth of data of a common scaffold being modified for divergent use.

    The omega-agatoxins from A. aperta consist of two subtypes of neuronal calcium channel toxins with different structural characteristics and binding specificities. Type I agatoxins, such as omega-Aga-I, may define a binding site on neuronal calcium channels that is common to both vertebrates and invertebrates. Type II omega-toxins, such omega-Aga-II, III and IV, share limited amino acid sequence similarity with Type I toxins. However, omega-Aga-IVA is able to block omega-CTX-GVIA (Conus geographus) resistant calcium channels. This use of structurally distinct toxins from common as well as divergent sources is an excellent manner in which to study a channel.


    The peptidic neurotoxins from A. aperta have similar locations of cysteine residues with neurotoxins from the venom of another North American funnel web spider Hololena curta as well as neurotoxins from the more distantly related Brazilian spider Phoneutria nigriventer (Wandering spider). This conservation of structure among these three species is interesting to view from a taxonomic standpoint in that venom peptide sequences may be useful as chemotaxonomic tools. Despite being the only lethal species amongst the three spiders, the toxins of the Phoneutria nigriventer share strong structural similarity, particularly in the location of the cysteine residues with neurotoxins from these other two spiders.

    While the lethal neurotoxin PhTx1 from Phoneutria nigriventer venom has a primary structure shows no homology to any other identified spider toxin, cDNA libraries constructed from the venom glands revealed that the structure of the preprotoxin initially synthesized by the Tx1 gene shows similarity in sequence and also in processing with the synthesis and processing of omega-agatoxin IA from A. aperta. Thus, this toxin may not be quite so unrelated but rather may represent a case of a spider that is taxonomically divergent, as P. nigriventer is from the more closely related two N. American species, with the venom diverging along with it.

    Delta Atracotoxin
    Unlike the American funnel web spiders, the venoms of Australian funnel web spiders are quite lethal, consisting of a large number of acute acting neurotoxins. These venoms slow the inactivation of primate sodium channels causing envenomation symptoms involving pain at the bite site, salivation, lachrymation, piloerection, generalized skeletal muscle fasciculation, sweating, nausea, vomiting, diarrhea, pulmonary edema, dyspnoea followed by respiratory failure, tachycardia and hypertension followed by hypotension and circulatory failure.

    The primary toxic components of the venoms of two species have been isolated and characterized. The lethal toxins from A. robustus and H. versuta venoms are the 42 amino acid peptide components robustoxin (atracotoxin) and versutoxin respectively. Versutoxin differs from robustoxin by only 8 amino acid residues. Disulfide-bridged cysteine residues at both the amino- and carboxy-termini and a triplet of cysteines at residues 14-16 makes these components unprecedented amongst neurotoxins
    "


    He knows his stuff, however he mentions (in bold) several groups of peptides which are quite big enough to give you an immune response. Unlikely, yes. Possible, definately.

    Do I have specific data for australian tarantulas, or indeed any other tarantulas of interest here? No - just the book I reference above. However, there is almost ALWAYS a potential for an allergic response. The "Colour Atlas of Human Poisoning and Envenoming" mentions that the localised swelling from most bites is an immune/histamine type response, and I have seen nothing so far which would suggest otherwise.

    Certainly, most spiders seem to employ the same tricks, which Dr Fry does include in the stuff above - that is to block ion channels; the stuff which keeps your brain ticking over. Localised necrosis is also mentioned as a possible effect from some spiders. I agree it's extremely unlikely, but it's there as a possibility!
     
  14. DrAce

    DrAce Arachnoangel

    See my most recent post above. While some suggest that there is no possibility for an immune response, a 42 amino acid peptide is more than enough. I've gotten antibodies from a peptide only a fraction bigger (45) in the lab.
     
  15. Cirith Ungol

    Cirith Ungol Ministry of Fluffy Bunnies Old Timer

    It wasn't entirely ruled out in the previous long discussion about this topic either, but also deemed very unlikely.
     
  16. DrAce

    DrAce Arachnoangel

    I've not seen it, but it makes me feel slightly vindicated.

    Can you post a link there?

    Incidentally, Dr. Bryan Grieg Fry is kinda cute. I recommend his site.

    He does seem more of a snake venom guy than a spider venom guy - although both would trump my bumblings into the area. I do know for a fact that 42 amino acids can give you an immune response.
     
  17. Cirith Ungol

    Cirith Ungol Ministry of Fluffy Bunnies Old Timer

    Not sure if you'll feel that vindicated after reading it, it was deemed so unlikely to almost being "impossible" so I guess we are landing in a zone of interpretation, at least regarding the old thread.

    Actually, I found two. I place them in cronological order:
    http://www.arachnoboards.com/ab/showthread.php?t=54244
    http://www.arachnoboards.com/ab/showthread.php?t=77826

    Edit:
    Wouldn't it be helpful for the sake of the discussion to make a distinction between localized allergic reaction and anaphylactic shock?
     
    Last edited: Sep 6, 2007
  18. Crotalus

    Crotalus Arachnoking Old Timer

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    Dr Ace, zero cases of anaphylaxis in the litterature (and there are no shortage of bite cases from those spider species) might give us a hint that we can rule it out.
    So, unless someone provide documented cases I think its correct to say it doesnt cause it.

    As you state yourself in your first reply here:
    "The magic words in that website are all there "Could" and "might"."

    I choose to leave those words out and let facts speak for itself.
     
    Last edited: Sep 6, 2007
  19. abarth

    abarth Arachnosquire

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    This is a bit OT, but reading all this I come to yhink of, what harm can a tarantula-bite actually do to a small child?
     
  20. DrAce

    DrAce Arachnoangel

    Again, Crotalus. I'm not sure we're sparring AGAINST each other, as oposed to nit-picking...

    However, we're not talking about everyone here. We're talking about someone who has an alergic shock reaction - something which by definition is rare. I, for one, would not like to say it's impossible, when there is a distinct possibility that it can happen.

    A large chunk of the earth's population does not live in daily interaction with tarantulas - particularly the Australian species. I doubt that there are a million people LIVING on earth who have been been bitten by one, and these sorts of severe reactions are likely to occur in less-than-one-in-a-million chances.

    On top of all this, the venom is not a highly purified substance, to my knowledge. There is a high chance that other proteins are present, any one of which are not-human, and therefore likely to induce a reaction.

    Again, I agree it's unlikely, but saying "it's never happened" is like a Ukranian Engineer working for Chernobyl saying "it's never happened so far...".

    Absence of evidence is not evidence of absence.

    I completely and utterly agree that there is no reason to be concerned. I don't lie awake at night, worried about getting tick-paralysis, and I will not be concerned about spider bites. But the chances are there, and the logic behind the declaration that it's impossible is flawed.