The myth of the white-tailed spider

“Man loses both legs and arms at risk after white-tail spider bite,” trumpeted a headline in the Daily Telegraph last week.

“White-tail spiders are commonly found in homes across the country, usually hiding in bedding and clothes draws [sic],” the newspaper went on, warning the spider’s bites “cause ‘necrotising arachnidism’, which is basically ulcerating skin loss”.*

As a certified arachnophobe, I’m happy to believe the worst of spiders, but really?

The myth of the flesh-eating white-tailed spider was exploded more than a decade ago by this prospective study, published in the MJA.

Researchers from the University of Newcastle studied 130 cases of confirmed white-tailed spider bites. All of the arachnid’s victims experienced some level of pain or discomfort from the bite, with less common effects including skin redness and itch.

How many suffered necrotic skin lesions? Zero, that’s how many.

Yet, the myth lives on. And not just in Australia or in relation to this particular, fairly inoffensive, spider.

US entomologist Dr Richard Vetter has written of similarly unsubstantiated claims about necrotic wounds caused by his country’s brown recluse spider, for example.

In some parts of the world, spiders are apparently venerated but, in the West at least, their association with disease goes back a long way.

Lead author of the 2003 MJA study, Professor Geoffrey Isbister, has traced the scapespidering back to medieval times, when the eight-legged creatures were blamed for spreading the Great Plague.

“The association with plague is thought to result from the fear of a disease of unknown cause and the need to attribute the disease to an external agent,” he wrote in the Lancet.

Because arachnids were seen as a plausible cause, “fear of disease manifested as anxiety and hysteria about spiders”.

Even more fanciful was the epidemic of “tarantism” that spread across southern Europe from the 15th to the 17th centuries and, according to Professor Isbister, is still occasionally diagnosed in the region today.

Allegedly caused by the bite of a tarantula, the condition brought with it sweating, pain, tremors, rigors and sometimes “madness”.

The only cure was to dance energetically for 3–4 days, a treatment enthusiastically embraced by residents of the southern Italian town of Taranto, where the disease originated.

They established dancing festivals, writes Professor Isbister, using tarantism as “an opportunity to resurrect orgies and attribute their unseemly behaviour to spider bites”.

I’m not aware it has led to orgies, but another myth exposed by Professor Isbister is the widespread belief that daddy longlegs are actually the most venomous of all spiders, “despite no reported bites and the venom never having been studied”.

That’s not just a Western urban myth. I was even told it when I was trekking through the jungles of Borneo, by a local guide eager to impress foreign visitors with the many dangers of his rainforest.

Spiders are pretty much always with us, and many of us fear them (it’s the scuttling legs!), so perhaps it’s not surprising they have so often been credited with superarachnid powers.

But, in most cases of spider bite, the perpetrator is not captured or identified by an expert, meaning that any alleged causal connection is pretty much conjecture.

And when even clinicians buy into the myths, it may put patients at risk.

As Professor Isbister makes clear, misdiagnosis of necrotising arachnidism may lead to failure to treat a condition that is actually there, such as basal cell carcinoma or various bacterial or fungal infections.

It’s clearly time for a more evidence-based approach to our eight-legged friends.

Apart from huntsmen, that is. I’d believe anything of them.

* The Daily Telegraph article and others were later modified to incorporate the views of experts questioning the spider’s role in this tragic Victorian case.

Jane McCredie is a Sydney-based health and science writer.

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