Spare us a thought down here in Australia!
The Funnel Web spider
Symptoms and Signs of Envenomation by Atrax robustus
In most cases of bites by this spider, little venom is injected and no symptoms develop. None the less, first aid should be promptly applied and medical attention sought without delay. If envenomation has occurred, the bite site may be extremely painful, although tissue necrosis is not seen. There is some evidence that prolonged immobilisation of venom in the tissues may lead to inactivation. Systemic symptoms can develop within minutes if effective first aid is not employed. They are due to the effect of atraxotoxin?s direct effect on nerves leading to the widespread release of neurotransmitter from somatic and autonomic nerves.
Symptoms and signs of envenomation include:
Numbness around the mouth and spasms of the tongue
Nausea and vomiting, abdominal pain, acute gastric dilatation
Profuse sweating, salivation, lacrimation, piloerection
Local and generalized muscle fasciculation and spasm, commencing in facial tongue or intercostal muscles, and including trismus, which may necessitate paralysing the patient with muscle relaxants in order to manage the airway
Dyspnoea
Confusion, irrationality, coma which may persist in the presence of normalized ventilation, oxygenation and blood pressure, and may be related to raised intracranial pressure
Hypertension, vasoconstriction, tachycardia and cardiac arryhthmias ? related to release and subsequent depletion of neurotransmitter
Widely dilated pupils, which may be fixed
Acute non-cardiogenic pulmonary oedema
Later, the severely envenomed patient may develop progressive hypotension and apnoea. These features may relate to depletion of neurotransmitter.
Several people have died after being bitten by Funnel Webs.
The Mouse Spider
Mouse spiders, which belong to the trapdoor family of spiders, are found throughout mainland Australia. They make vertical burrows lined with silk, and with a door at the entrance.
Mouse spiders are aggressive, and will adopt an attacking posture when threatened, rearing up on their hind legs. They are thickset, with large fangs capable of inflicting a painful and potentially serious bite. Mouse spiders are occasionally mistaken for funnel web spiders, and their venoms appear to possess some similarities to those of funnel webs.
The female M. occatoria produces copious amounts of highly toxic venom, which was shown to be potentially as dangerous as that of the Sydney funnel web spider on preliminary toxicity testing performed at the former Commonwealth Serum Laboratories.
Recent work on venom from the male M. bradleyi suggests that it affects presynaptic transmitter release in a manner similar to that of the Blue Mountains funnel web spider (H. versuta) venom, and that funnel web spider antivenom attenuates this effect.
The Redback Spider
he time course and the actual symptoms are highly variable, but progression of the illness is generally slow, and symptoms may persist for weeks after an untreated bite. The acute symptoms include:
· Immediate pain at the bite site +/- erythema and swelling .
· Pain progressing to involve the entire limb
· Painful or tender regional lymph nodes.
· Sweating, sometimes affecting only the bitten limb initially, and sometimes over bizarre distributions distal to the bite site
· Nausea, vomiting, abdominal pain
· Headache
· Migratory arthralgia
· Fever
· Restlessness and insomnia
· Hypertension
· Neurological symptoms associated with the neuromuscular blockade and possibly catecholamine release caused by a-latrotoxin
The exact mechanism(s) by which the toxins produce the observed clinical effects are poorly understood, as is the precise cause of death. No deaths have been reported since 1955, a year before the introduction of redback spider antivenom in Australia. Unusually, antivenom may be effective even if administered several weeks after the bite.
The White-tailed Spider
White tailed spiders are found in most areas of Australia, and are common in urban dwellings. They are readily identifiable by their cylindrical body shape and the presence of a white or grey spot on the end on their abdomen. They are active hunters, preying upon other types of spiders, and may be found roaming inside houses, especially in warmer weather. White tailed spiders have been implicated in some cases of Necrotising Arachnidism (skin breakdown or ulceration following spider bites). The incidence of ulceration or necrosis following white tailed spider bite is not known. The majority of cases appear not to develop ongoing ulceration, although blisters and redness are common.
White tailed spiders are readily identified by a distinctive white spot on the abdomen, present in both males and females. They are often found in bedding, or in clothing that has been left on the floor, and are mainly active at night, when they hunt for prey of spiders and insects. It is unknown whether the male and female are equally associated with skin necrosis. In most spider bite cases in which Lampona Sp have been positively identified, only a mild localised reaction or blister ensues. There is, however, a small number of cases of significant tissue loss after a witnessed bite by these spiders.
The Bird-eating Spider
Bird-eating spiders are amongst the largest spiders found in Australia. These large primitive spiders, native to northern and inland Australia, excavate long burrows from which they emerge at night to ambush prey including spiders, insects, frogs, lizards and sometimes small birds. Some species are currently being collected from the wild and being sold as pets in suburban pet shops, increasing the likelihood of bites by these large arachnids. Reported symptoms includes nausea, vomiting, sweating and general malaise. No deaths have been recorded. There is no antivenom available.
Finally, here is an example of Necrotising Arachnidism, the horrible flesh-eating condition that occurs with many Australian spider-bites. The ones that don't kill you, that is...
Nice, eh?
This is only a subset of the nasties you get down here.
Mr Mephisto