The Spider Research Project

Necrotising Arachnidism

Evidence is mounting that more than one kind of spider can cause the phenomenon, known as necrotising arachnidism, and very little is known about the species responsible. The top two suspects are the White Tail spider and the Wolf spider.
As the problem is uncommon, and not seen officially as a threat to life, health authorities and governments have not given it high priority, and as a result (with no heavy investment in research funding), scientists are unlikely to come up with answers, let alone antidotes.
The normal process of tissue death, starts because of a loss of blood supply - such as in frostbite or injury - or because of bacterial action. On the body surface it results in gangrene, which can spread to healthy tissue. Necrosis from animal venoms, such as the tentacles of jellyfish is different, usually self-limiting in area and duration, and not gangrenous. Often the body can replace the damage; wheals from jellyfish stings may be replaced by scar tissue - but in severe cases of necrosis from spider bites, the loss is extensive and irreversible, reaching through all layers of skin.
Skin death may start with surface blistering, or with darkening below, and can be rapid and agonising. It can be accompanied by drastic attacks of vomiting and diarrhoea. Or, it may be gradual with very little pain. One case in Melbourne had a fast onset and a slow, relentless continuation. The only way of repairing the damage usually involves skin grafts, and sometimes amputations.
A bacterium, Myobacterium ulcerans is carried in the venom, and it is believed this microscopic organism does the damage, causing a spreading, infected ulcerous sore. According to Bert Brunet, the author of "Spiderwatch", application of amino acid L-Cystine ointment has in some cases counteracted the necrotic venom. He has also found that the application of aloe vera in ointment or fresh leaf form can help neutralise the effects of the bite, and recommends applying it generously over the wound three or four times a day until the wound heals.

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