Australian Funnel-web Spiders:
At present 35 species of these highly aggressive spiders have been characterised and are grouped into two genera, Atrax and Hadronyche. The Atrax genus consists of only three species, including the infamous Sydney Funnel-web (Atrax robustus). The genus Hadronyche contains the remaining 32 species divided into the six species groups; adelaidensis, modesta, illawarra, cerberea, infensa, and lamington (Gray 1987). The distribution of Funnel-webs in Australia is more widespread than commonly thought. Species range along the East Coast of the continent from Tasmania to mid Queensland, with an isolated pocket near Adelaide.
The venom of these spiders consists of a large number of acute neurotoxins, mostly peptidic in nature. Very little work has been performed on the venom of any Australian Funnel-web at the molecular level, with most work concentrating on the pharmacology of the venom from Atrax robustus (Sydney Funnel-web) and Hadronyche versuta (Blue Mountains Funnel-web). The primary toxic components of the venoms of these two spiders have been isolated and characterised. The two toxins are the 42 amino acid peptide components Robustoxin (Sheumack, Claassens et al. 1985) and Versutoxin (Brown, Scheumack et al. 1988) respectively.
These components slow the inactivation of primate sodium channels (Nicholson, Little et al. 1996) causing envenomation symptoms involving pain at the bite site, salivation, lachrymation, piloerection, generalised skeletal muscle fasciculation, sweating, nausea, vomiting, diarrhoea, pulmonary odema, dyspnoea followed by respiratory failure, tachycardia, and hypertension followed by hypotension and circulatory failure (Nicholson, Willow et al. 1994) . Curiously enough, Robustoxin is only present in the venom of the male Atrax robustus, however Versutoxin is present in the venom of both male and female Hadronyche versuta.
A polyvalent antivenom was discovered in 1980 (Sutherland 1980) and has been reported for successful treatment of envenomation from Hadronyche formidabilis (Northern Tree Dwelling Funnel-web) (Knight and Sutton 1982) , Hadronyche versuta (Blue Mountains Funnel-web), Hadronyche cerberea (Southern Tree Dwelling Funnel-web), Hadronyche infensa (Toowoomba Funnel-web) (Dieckmann, Prebble et al. 1989) , and Atrax robustus (Sydney Funnel-web).
All Funnel-webs should be considered as potentially lethal and treated with the appropriate respect and care. Any bites by Funnel-webs, or spiders thought to be Funnel-webs (intact capture of the spider for identification is of valuable assistance) should receive medical attention. The suggested first aid procedures for a Funnel-web bite is the application of a constriction bandage to the bitten limb followed by medical attention. Often dry bites (a bite without actual envenomation) occur, however first aid procedures should be followed for ANY bite.
For more information regarding funnel web spiders, contact David Wilson at the University of Queensland
References:
Brown, M. R., D. D. Scheumack, et al. (1988). "Amino acid sequence of versutoxin, a lethal neurotoxin from the venom of the funnel-web spider Atrax versutus." Biochem. J. 250: 401-405.
Dieckmann, J., J. Prebble, et al. (1989). "Efficacy of funnel-web spider antivenom in human envenomation by Hadronyche species." The Medical Journal Of Australia. 151(December 4/18): 706-707.
Gray, M. (1987). Distribution of the Funnel-web spiders. Brisbane, Museum of Queensland.
Knight, J. and L. Sutton (1982). "Successful treatment of Atrax formidabilis envenomation." The Medical Journal Of Australia (October 30): 434-435.
Nicholson, G. M., M. J. Little, et al. (1996). "Selective alteration of sodium channel gating by Australian Funnel-web spider toxins." Toxicon 34(11/12): 1443-1453.
Nicholson, G. M., M. Willow, et al. (1994). "Modification of sodium channel gating and kinetics by versutoxin from the Australian funnel-web spider Hadronyche versuta." Pfluegers Arch. 428(3-4): 400-9.
Sheumack, D. D., R. Claassens, et al. (1985). "Complete amino acid sequence of a new type of lethal neurotoxin from the venom of the Funnel-web spider Atrax robustus." FEBS 181(1 - February): 154-156.
Sutherland, S. K. (1980). "Antivenom to the venom of the male Sydney Funnel-web spider Atrax robustus. Preliminary report." The Medical Journal Of Australia 2(October 18): 437-441.
Latrodectus hasselti (Red-back and Widows)
The venom of the Latrodectus genus is contains some of the most potent biologic toxins found. These produce their effects through destabilization of cell membranes and degranulation of nerve terminals resulting in the release of neurotransmitters. Typical envenomations, of varying degrees with mactans (Black widow) and hasselti (Red-backed spider) being the two most toxic members of the genus, produce painful abdominal cramping and rigidity accompanied by severe hypotension. As is true will all poisonings, the very young or elderly are at the greatest risk as are those with preexisting cardiovascular disease.
L. hasselti (Red backed spider) is a very toxic specie with clinical effects are virtually identical to that of the Black widow. No toxins have been specifically reported for this specie, but due to the extreme simillarity of symptoms it is logical to conclude that specific venom proteins found in mactans (black widow) or close analougs of these proteins are present in the venom of hasselti.
Lycosa (Wolf spiders)
Despite its relatively large size, and morphological similarity with
Loxosceles, the wolf spiders are essentially nonvenomous to humans.
In typical cases there is seldom anymore than mild localised pain and very
rarely and cutaneous necrosis or systemic effects from this cytotoxic venom
Selenocosmia stirlingi (Whistling spider)
Although clinical references concerning bites from this genus are scarce, in laboratory testing, using single doses, Selenocosmia stirlingi venom was shown to be highly toxic to rats, and therefore potentially toxic to humans
