Of all the spiders whose toxicity is currently known, probably the most toxic are the funnel-web spiders of Australia (of the genera Atrax and Hadronyche). Their bites are lethal to small children within minutes or hours and adults within 24 hours – but, having said this, there have been no Australian fatalities since anti-venom was developed.
Widow spiders of the genus Latrodectus cause a fair bit of morbidity. However, death from widow bite is pretty much a thing of the past as supportive care and anti-venom has provided tremendous relief. One mitigating factor is that deaths during the early part of the 20th century may have been due to bites that occurred in men in outhouses bitten on dangling genitalia where thin skin and heavy vasculisation allowed for quick introduction of venom. Indoor plumbing has minimised widow bites.
Loxosceles sp. Smithsonian Institution
“Brown recluse and related spiders of the genus Loxosceles have a widespread reputation for causing damage, but, like Phoneutria spiders, there is a great deal of exaggeration. Most recluse bites cause only minor problems. About 10% develop significant skin necrosis but even so, loxoscelism experts recommend these can be treated with minimal intervention. Fewer than than 1% of recluse bites become systemic, typically in children, and can cause death in 12 to 30 hours. However, dialysis and hydration can reverse the systemic effects.
The media likes to stir up anxiety using toxic spiders in attempts to attract an audience. However, for most of us, spiders are less of a threat than driving.
Rick Vetter does not work for, consult to, own shares in or receive funding from any company or organisation that would benefit from this article, and has no relevant affiliations.