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Spider Bites

It seems to happen several times a year, a gruesome image of a badly infected leg, arm or hand in the national papers with a spider bite stated as the cause.  

But when you look into the details, you often discover that things just don’t add up. It seems all too easy to blame spiders for bacterial infections.

False-widow spiders tend to cause sensation in the media, but Professor David Lalloo, of the Liverpool School of Tropical Medicine says;

“These spiders are not aggressive and bites from them are not dangerous; they may cause short-lived pain and in rare cases, may make people feel unwell for a day or so, but there is no record of them causing serious illness or death.”

So here are some facts about spiders and their bites;

Noble False-widow (Steatoda nobilis)© Steven Falk

Noble False-widow (Steatoda nobilis)© Steven Falk

  • Most British spiders couldn’t bite you if they tried; their fangs are too small or weak to penetrate human skin.
  • Most large spiders are not inclined to bite a human – you can handle hundreds of large house or garden spiders and never get bitten.
  • If a larger spider does manage to bite you, the symptoms are usually like a pin prick, milder than a wasp or bee sting.
  • The notorious Noble false-widow (Steatoda nobilis) does indeed have a more venomous bite than other British species. It injects a neurotoxin which may cause localised pain, minor swelling, and in extreme cases nausea within a few hours (but not days).
  • There are no proven cases where the Noble false-widow has caused death, coma or permanent injury.
  • Its neurotoxins do not result in ‘necrosis’ i.e. the gangrene-like infections described in the media – this results from a bacterial infection which could come from any source including scratching a mosquito bite, scratch or splinter wound with dirty fingers.
  • An allergic reaction to a spider bite is theoretically possible, but has never been recorded, even in people who are allergic to bee or wasp stings.
  • There is no proven link between spider bites and bacterial infection and there are still no confirmed cases of serious injury resulting directly from the bite of a native spider in Britain.
  • Female Noble false-widow spiders are notably sluggish, ponderous, solitary and non-aggressive, they will never run or jump at you in an aggressive manner as some people describe.
  • Sometimes venomous spiders are introduced with produce or goods from abroad. Spiders found in grocery areas of shops should be treated with caution.

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