Are White-Tailed Spiders Really That Dangerous?

Image: Robert Raven

Recent news reports that a man had both his legs amputated after being bitten by a white-tailed spider have again cast this spider in a negative light. Experts have since said amputations may have been wrongly blamed on a spider bite, and authorities now consider a bacterial infection to be responsible for the man’s injuries. Despite this, the damage to the largely harmless white-tail may have been done.

The venom from the white-tailed spider is listed as non-lethal. It has not been shown to cause necrotic ulcers, which could result in the need for amputation. And there has never been any clear evidence necrotising arachnidism – the name give to a syndrome where the skin blisters and ulcerates following spider bites – has been seen in Australia.

There is currently no clinical test to determine if you have been bitten by a spider. And there is no blood or swab test that can be performed to positively identify what spider it is if a bite is suspected. Whether it is a bite from a spider or another insect, the management is the same – most will get better without any medical treatment.

Spiders in Australia

The majority of spiders in Australia are voracious predators of insects. For the most part, they play a useful role in lowering insect numbers.

The venom transmitted through bites of some Australian spiders can cause harm to humans and even be life-threatening. The better known of these are the redback spider (Latrodectus hasselti), and the funnel-web spiders (genera Atrax and Hadronyche). Antivenom is available for both spiders.

Redback spider venom can cause a lot of pain. Advice would be to go to hospital if pain lasts for longer than a few hours and simple pain relief is not helping. Funnel-web spider venom can cause local swelling in addition to increasing heartbeat, salivation, muscle spasms and respiratory distress (trouble breathing).

Without appropriate first aid, quick access to hospital and antivenom, these bites can be lethal. For the “big black hairy” funnel-webs, appropriate first aid needs to be applied and it is advisable to call 000.

The redback spider is considered one of the most venomous to humans in Australia. [Image: graibeard/Flickr, graibeard/Flickr]

Other spiders that have concerning bites include the trapdoor, whistling, sac, ground, orb and huntsman spiders. These may cause milder symptoms such as headache, swelling and pain, which does not last for a long time.

The white-tailed spider

White-tailed spiders (Lampona sp.) can be recognised by their cylindrical body shape and a white or grey spot on the end of their abdomen. They are found in eastern and most southern areas of Australia and New Zealand.

These spiders are active hunters, preying on other types of spiders and insects. They may transiently roam inside houses, especially in warmer weather, where they may be found in bedding or clothing that has been left on the floor.

One study of over 70 spider bite cases in which white-tailed spiders were identified showed patients experienced only a mild localised reaction, such as swelling, local pain or headache. To date clinical research has not been able to associate tissue loss with the venom of these spider bites.

Flesh-eating bacteria

The man at the centre of the recent story linking amputations to a white-tail spider bite was said to have a “flesh eating” infection. But there is a very low probability of an association between spiders and necrotisisng fasciitis (commonly known as flesh-eating disease).

Of course, any injury that causes a break in our skin leaves the capacity for bacteria to enter our body. Therefore be sure to keep an injury area clean. Questions have been raised as to the possibility of a spider introducing infections, but again, despite it being theoretically possible, it is unlikely.

Contributing factors to infection are if people have conditions such as diabetes or take medications, such as steroids like prednisolone, that lessen the body’s ability to fight infection.

How to prevent spider bite

  • Leave them alone
  • wear gloves if gardening
  • humanely remove spiders from your home and limit hiding spaces where possible inside the home
  • knock out shoes before putting them on; these are nice quiet homes for spiders.

For first aid after a spider bite, please see the Australian guidelines. Many bites don’t result in envenoming and death is very rare, so it is important to remain calm. But seek medical attention if there are concerning symptoms such as those described above: difficulty breathing, increased heartbeat and pain lasting longer than an hour.

The Conversation

Ronelle Welton, Scientist AVRU, University of Melbourne and Bill Nimorakiotakis, Associate Professor, Epworth Hospital

This article was originally published on The Conversation.


Comments

    How to prevent spider bite
    *Leave them alone
    *Leave them alone
    *Leave them alone
    *Leave them alone
    *Just leave them the fuck alone a'ight.

      Want fewer bugs in your house? Leave the spiders alone. They are nature's pest control.

    How to prevent spider bite
    *Mortein
    *Mortein
    *Mortein
    *Mortein
    *Just keep spraying until they explode a'ight.

    How to prevent a spider bite (in order of manliness)
    *pick them up with you bare hands and throw them outside
    *squash them with you bare hand
    *squash them with some form of utensil/tissue/shoe etc
    *(not sure where this should go on the list) fry them with a spray can flamethrower
    *use a bug spray
    *leave them alone
    *run around in circles screaming in a high pitch until they explode a'ight.

      Leave them alone is the manliest. Just a little spider bro trying to be the best room mate he can.

        i have two kids under 4, that option doesnt exist in my house hole UNLESS its a daddy long legs,

          Heh. Your house hole =D
          I have rules on which spiders can exist around the house. Redbacks and white tails are NOT on that list. I love the little jumpy spiders. They have free reign of the joint!

            that's where you were supposed to say "HOLE!? LUXURY! we grew up in the middle of a road under a sheet of newspaper and were thrashed to sleep with a broken bottle every night while our father put out his cigarettes on our bare skin"

    nuke them from orbit.. its the only way to be sure

    I have a theory as to how a white tail spider may possibly cause necrotising arachnidism but only under certain conditions.

    When I lived in Tasmania in the 80's I once squashed a white tailed spider, within a few seconds an extremely long and thin worm (compared to the spider) started wriggling out of the spider's abdomen, I recall it was around 2 inches long which was probably 3-4 times the length of the spider. I have later discovered these are called gordian worms or horse hair worms.

    What if the existence of this parasitic worm within a host spider is somehow related to what seems to be sporadic reported cases of necrotising arachnidism from white tails? Perhaps there is something additional in either the venom or saliva (do spiders even have saliva?) that is only present when hosting this worm?

    Would like to discuss this further with Ronelle and Bill if possible to see if it holds water.

    Edit: Not sure why my previous message was so slow in being moderated but am posting it again without the link to see if that helps.

      They do have saliva. They use it to liquify their meal as they can't chew only drink.

      Way to give me nightmares!

      I was bitten by a whitetail once and ever since I have had eczema like rash on it. My ugly foot I like to call it.

    As someone who lives in South East Qld, I was always taught, year after year, in professional first aid refreshers that there's an alarming coincidink between white tail bites and necrotising fasciitis.
    They did say that they weren't sure whether the spider itself was responsible or whether it was bacteria from the rotting leaf matter where the spiders live getting in the wound; but if you get the former, watch out for the latter.
    I do know at least one person who has a permanent necrotic wound they said came from a white tail bite.
    As far as leaving them alone, it's good advice, except that white tails live in mounds of rotting vegetation, so, if you are gardening, it's kinda hard to see 'em coming. My solution? Bee-keeper suits for all trips into any part of Australia that isn't inside your house. Even then I tend to wear one if it isn't too hot. You get used to it.

    Oh dear, all this time I didn't realise these little dudes were the actual White Tip that everyone refers to. Been picking them up with a tissue and even bare hands to get rid of them. Ocean: 1, Darwin: 0

    My nuke them all from orbit comment earlier is still valid

    I have been bitten with only mild pain as a result, but I have witnessed a friend being bitten and within 3 hour he had a large necrotising wound that appeared to be beyond painful. When attending the hospital with him the duty doctor advised that this was most likely cause by bacteria either on the spider or from the location where the bite ocurred, which was a pretty dank creek (we were chasing small fish for an Oscar to eat).

    He had a nasty hole in his arm for a couple of weeks which is now a bright red scar.

    Unfortunately most pest exterminators play on this myth to drum up business. This particular spider hunts other household spiders. It's a shame that it will eventually be wiped out by ignorance and greed.

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