Tarantula Venom Properties

4 years 2 months ago #71505 by Taki Tsonis
And another interesting link, even the venom of the infamous Brazilian Wandering spider Phoneutria has seemingly been grossly over exxagerated.

'Allergic and foreign body Araneism: tarantulas.
The tarantulas of the Family Theraphosidae are the world’s longest-lived and largest spiders (18–24-cm leg span), and are among the most docile and brightly colored and patterned of all spiders. Tarantulas continue to be popular household pets, with environmentally threatened and endangered Amazonian species often imported worldwide. Tarantulas live in most tropical regions of the world, and are very common in the New World with more than 1,500 species, and 40 species in the southwestern United States alone. They are very territorial and stick close to their birthplaces, do not build webs, and live in underground burrows beneath rocks and embankments. Females prefer to remain in their burrows with their large families and can live for 25–30 years. Males rarely live for more than a year after reaching maturity by the age of 10–12 years. Tarantulas rest in their burrows or shady spots during the day and hunt at night. They have poor eyesight and detect and ambush prey by sensing vibrations. Although tarantula bites in dogs are often fatal, tarantulas rarely inflict envenoming bites on humans.65 Their major form of defense is to launch their urticating hairs posteriorly and rapidly retreat from threats.

The venom of the U.S. tarantula, Aphonopelma hentzi, contains a mixture of nucleotides, spermine, and, principally hyaluronidase, and resembles scorpion venom in composition and biologic effects. Escoubas and others have now demonstrated that tarantula venom components also contain a variety of specific peptide ligands that target specific neuroreceptors in excitable cell cationic channels, particularly sodium, potassium, and calcium cationic channels.66 Recently, Bode and others used a tarantula peptide ligand (GsMtx-4) from the venom of Grammostola spatulata to suppress the incidence and duration of induced atrial fibrillation in rabbit hearts.67 The investigators concluded that the antiarrhythmic effects of GsMtx-4 were due to specific inhibition of the potassium-selective, atrialstretch-activated ion channels.67 In addition, they suggested that GsMtx-4 could be the first of an entirely new class of antiarrhythmics directed against the causes rather than the symptoms of atrial fibrillation.67

Tarantula envenoming in humans usually causes mild stinging, resembling a bee or wasp sting, with minimal surrounding inflammatory reaction, no dermonecrosis, and no serious systemic sequelae.65 Although tarantula bites are usually innocuous in humans, tarantula bites are often lethal in domestic animals, particularly dogs.65 In a combined nested-prospective study of spider bites and a retrospective case series of definite tarantula bites in humans and dogs in Australia, Isbister and others described nine tarantula bites in humans and seven in dogs.65 The 16 bites included 2 bites each by Selenocosmia spp. tarantulas and Phlogiellus spp. tarantulas.65 The nine human bites caused only mild effects including local pain, severe in four cases, puncture marks, and transient bleeding from puncture sites.65 Mild systemic toxicity occurred in one of the nine human cases.65 All seven canine victims died within 0.5–2 hours of the confirmed tarantula bites.65

Four genera of New World tarantulas (Acanthoscurria, Brachypelma, Grammostola, and Lasiodora) and many other tarantula species possess several types of urticating hairs on their dorsal abdomens, which can be flicked off by the thousands to irritate and incapacitate pursuing aggressors. In human victims, these urticating hairs can penetrate the skin causing severe pruritic reactions or lodge in the cornea causing ophthalmia nodosa.68–,73 In a classic investigation, Cooke and others described and classified four types of tarantula urticating hairs, ranging in length from 0.6 to 1.5 mm and distinguished by distal barbs on electron microscopy.73 The U.S. tarantula, Aphonopelma hentzi, possess only Type I hairs that cannot deeply penetrate the skin, but can cause ophthalmia nodosa.73 Type II hairs are not launched in the face of attackers, but are defensively incorporated into tarantulas’ tunnel retreats.73 Type III hairs can penetrate up to 2 mm in human skin, and are most likely to cause intense skin inflammation and ophthalmia nodosa.73 Type IV hairs are found only in the South American Grammostola tarantulas, and are designed to induce irritation in the upper respiratory tract of pursuers.73

Although ophthalmia nodosa was initially reported after caterpillar hairs lodged in human corneas, ophthalmia nodosa with transient, steroid-responsive keratoconjunctivitis has also been reported in association with the handling of pet tarantulas, often by children.68–,75 In 1997, Blaikie and others reported three British cases of keratoconjunctivitis after handling domestic pet tarantulas.71 One patient with a pet Thailand black tarantula (Haplopelma minax) presented with a steroid-responsive ophthalmia nodosa characterized by transient anterior chamber inflammation and no long-term sequelae.71 The other two patients, both of whom handled pet Chilean rose-haired tarantulas (Grammostola cala), developed more serious panuveitis lasting for years, and leading to glaucoma and reduced visual acuity in one patient.71 In 1998, Belyea and others reported another case of ophthalmia nodosa in a 17-year-old American girl with a pet Chilean rose-haired tarantula.72 Following tapering topical steroids, all ocular inflammation and associated periorbital inflammation resolved by 10 months with two urticating hairs still lodged in the corneal stroma on slit-lamp examination.72

The management of tarantula bites should be conservative and symptomatic with thorough wound cleansing, tetanus prophylaxis, elevation of the bite extremity, immobilization, and oral analgesics as needed. All superficially embedded urticating hairs that can be identified by microscopy or slit-lamp examination should be removed if possible, and topical or systemic antihistamines and corticosteroids prescribed for pruritus from allergic response to fragmented and remaining urticating hairs.68–72,75 Prolonged topical ophthalmic corticosteroid therapy, rather than corneal excision, is often indicated for ophthalmia nodosa due to embedded corneal tarantula hairs.68–72,75 Patients recovering from urticating hair-induced ophthalmia nodosa should be followed by an ophthalmologist with periodic slit-lamp examinations and visual acuity and intraocular pressure measurements.68–72,75 If enthusiasts must handle their pet tarantulas or even clean their terrariums, they should wear gloves and eye protection, avoid rubbing their eyes, and thoroughly wash their hands after any contact with tarantulas or their terrariums.71,75

Other spider-induced injuries.
In addition to the eye injuries caused by tarantula hairs, both Fuller and Isbister have described acute conjunctivitis following eye contact with squashed spider contents.76,77 Fuller reported a patient who developed acute conjunctivitis, periorbital edema, and mild systemic toxicity following eye contact with squashed black widow (Latrodectus hesperus) contents.76 Recently, Isbister reported a 46-year-old male who smashed an unidentified spider with a newspaper and suffered immediate eye pain, severe photophobia, acute conjunctivitis, periorbital edema, and loss of visual acuity.77 Following topical anesthesia and vigorous eye irrigation, the symptoms and signs resolved over 2 hr.77 Other unusual spider injuries include urticaria caused by skin-embedded tarantula hairs, and occupational asthma caused by the inhalation of tarantula hairs.78,79'

You can take an Aphonopelma to crickets but you can't make it eat!

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4 years 2 months ago #71514 by Stanley A. Schultz

Taki Tsonis wrote: Hi Stan, maybe it's too early in the morning but what am I looking for in that link? :laugh:

Allergic reaction to spider venom. PubMed is a listing of all known medically oriented scientific papers (at least in the English language), and is maintained by a branch of the US government as an aid to research, and a general resource to the public.

If you see any publication that interests you, you can either:

1) Take the reference data to just about any college or university library near you and they'll help you get a copy of the publication.

2) Track down the author(s) of the publication and they'll send you a copy of the paper (usually a pdf via the Internet these days).

3) Hunt up an Internet forum for professionals interested in the subject (e.g., toxicology, allergens) and ask for a copy of the paper. Even if they're not one of the authors, most specialists keep libraries of publications for their own reference, and while it violates most copyright laws, they'll surreptitiously send you a copy.

It is interesting to note that PubMed, one of the most complete data bases of medical publications, only lists one or two papers discussing allergic reactions to spiders, and those deal with reactions to the urticating bristles or microscopic fragments of molted skins! All the other papers deal with spider mites (a completely different creature) or some arcane biochemical property of some arachnid peptide or other organic chemical.

Apparently, dedicating the remainder of one's life to the study of allergic reactions to spider venoms would not be a good career choice!

We had to get rid of the kid.
The tarantula was allergic.

The Tarantula Whisperers!
Stan Schultz
Marguerite Schultz
Co-authors of the TARANTULA KEEPER'S GUIDE, now in its third edition!
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4 years 2 months ago #71563 by Edrich

Apparently, dedicating the remainder of one's life to the study of allergic reactions to spider venoms would not be a good career choice!

A lot off people assume that if one is allergic to a bee sting that you could be allergic to tarantula venom.
This would make that assumption absolute rubbish!

"When spider webs unite they can tie up a lion"

Edrich du Plessis

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