CPR First Aid

The Dangers of a Funnel-Web Spider Bite

The Dangers of a Funnel-Web Spider Bite

Funnel-web spiders are considered one of the most dangerous spiders in the world as they have toxins that may kill humans. Unfortunately, these dangerous spiders are found in Australia. Let’s find out if, in Perth, there are reported encounters and bites from these funnel-web spiders. In addition, tips on first aid practices for spider bites will also be discussed.

Funnel-Web Spider Bite

The funnel-web spider has at least forty species. One of them is called Atrax robustus which is responsible for all recorded deaths (13) and many medically serious spider bites as stated by the Australian Museum. In addition, a study by The Medical Journey of Australia identified 77 cases as severe funnel-web spider envenoming. It included cases when antivenom was not yet available wherein:

  • 6 adults and 7 children died
  • 13 incurred non-fatal bites

When an anti-venom was introduced, 48 of the 77 cases were treated.

Symptoms of a Funnel-Web Spider Bite

The following symptoms may be felt if a funnel-web spider bites you:

  • Tingling around the mouth and tongue.
  • Facial muscle twitching.
  • Nausea.
  • Vomiting.
  • Profuse sweating.
  • Salivation.
  • Shortness of breath.

There may also be a development of agitation, confusion, and coma. These are associated with hypertension, metabolic acidosis, dilation of the pupils, generalised muscle twitching, and pulmonary oedema. 

First Aid Treatment to a Funnel-Web Spider Bite

The dangerous health effects of a funnel-web spider bite may be prevented by:

  1. Calling 000 for emergency help.
  2. Immediately respond to it with first aid such as applying a pressure immobilization bandage.
  3. Treatment using anti-venom by a doctor.

Step 2 in the mentioned first aid management for a funnel-web spider bite only slows down the movement of the venom. The mainstay of the treatment is anti-venom.

How to Apply a Pressure Immobilization Bandage?

This first aid step applies not only to funnel-web spider bites but also to other animal bites and wounds. It may be done by:

  1. Having the victim lie down to prevent walking or moving around.
  2. Applying a firm bandage over the bitten area.
  3. Bandaging the entire limb tightly.
  4. Applying a splint to the limb.

Doing the above may be confusing to do, especially for non-first-aiders. Fortunately, these are now a part of the contents of a first aid course in 123C Colin St West Perth 6005. In these accredited first aid courses, you may acquire the skills and knowledge to appropriately perform first aid to emergencies like spider bites that may contain venom.

The Male Funnel-Web Spider’s Venom

Among male and female funnel-web spiders, only the male contains the very toxic venom. It is called Robustoxin (d-Atracotoxin-Ar1) which is a unique component that severely affects the nervous systems of humans and monkeys.

Description of Robustoxin (d-Atracotoxin-Ar1)

The toxin produced by a male funnel-web spider is under the protein class, which is a low-molecular-weight neurotoxic polypeptide, according to the Toxin and Toxin Target Database (T3DB). It is in a liquid state and contains different compound types. Its route of exposure is through injection (sting/bite).

The Mechanism of Toxicity by the Male Funnel-Web Spider’s Venom

The funnel-web spider’s venom inhibits the insect and mammalian voltage-gated sodium channels. Then, it binds to site 3 in tetrodotoxin-sensitive sodium channels. This process slows their inactivation and causes a prolongation of action potential duration. When this occurs, there is a repetitive firing in autonomic and motor nerve fibres.

The Metabolism of the Male Funnel-Web Spider’s Venom 

Removing the funnel-web spider’s venom may be done either by:

  • Opsonization via the reticuloendothelial system (which involves the liver and the kidneys).
  • Degradation through cellular internalization via the lysosomes (membrane-enclosed organelles that contain an array of digestive enzymes, including several proteases).

Health Effects of the Male Funnel-Web Spider’s Venom 

The following circumstances may happen if a funnel-web spider bites you and injects its venom:

  • Progressive hypotension.
  • Raised intracranial pressure resulting from cerebral oedema.

Death from a funnel-web spider bite may result from any of the above effects.

The Female Funnel-Web Spider

According to the Australian Museum, the poisonous chemical found in a male funnel-web spider is not present in a female one. This may be the reason why female funnel-web spider bites have not reported any deaths so far.

Why there are More Spider Bites from a Male Funnel-Web?

Aside from the venom being present only in the male funnel-web spider, they also wander at night during the warmer months of the year (November-April). They do so to look for females in their burrows. They often wander in suburban gardens where they may be trapped inside houses or garages. These are some common places where encounters with humans may happen that may lead to a spider bite incident. Thankfully, this may still be treated with the help of a first aid response and the use of antivenom.

The Funnel-Web Spider Antivenom

Fortunately, the antivenom for this dangerous spider is also distributed in Australia according to NPS Medicine Wise. It contains an active ingredient that is injected to neutralise the effect of the funnel-web spider’s venom.

How did a Funnel-Web Spider Antivenom look Like?

The Funnel-Web Spider Antivenom is in a vial that is in the form of a freeze-dried powder. Its contents are dissolved in sterile water before use. Once done, the solution becomes colourless and its clearness may range from clear to slightly milky.

The Dose for the Funnel-Web Spider Antivenom

The dose for the antivenom is the same for both adults and children. It contains two vials that may be repeatedly injected as necessary.

Side Effects of the Funnel-Web Spider Antivenom

The following are considered common side-effects of the funnel-web spider antivenom:

  • Allergic reactions.
  • Rash.
  • Hives.

Below are the possible serious side effects of the venom:

  • Swelling of certain parts of the body such as the face, lips, or tongue.
  • Wheezing, shortness of breath, or trouble breathing.
  • Rapid, shallow breathing, cold, clammy skin, a rapid, weak pulse, dizziness, weakness, and fainting.
  • Swellings on the skin may be pinkish and/or itchy.
  • Fever, swelling, skin rash, joint pains, and swelling of the glands (may be in the neck, armpit, or groin).

These may occur anytime up to two weeks after the injection. It is advised to inform your doctor immediately if you experience any of the above.

Identifying Funnel-Web Spiders

The male funnel-web spiders are built more lightly than the females. In addition, they have the following characteristics:

  • Medium to large.
  • Black to brown body colour.
  • Sparsely-haired and glossy hard carapace covering the front part of the body.

A male funnel-web spider may only have a body length of up to 25mm while the female ones may reach over 35mm. In addition, males have slender legs, and a spur is located on the third segment of the second leg.

Location of Funnel-Web Spiders

Below are the identified places where funnel-web spiders live:

  • Different forests (moist, dry, upland, rainforest).
  • In or under rocks, rotting logs, crevices, rot and borer holes in rough-barked trees
  • Rockeries and dense shrubberies in gardens.
  • Holes in the ground.

People who do gardening and dig soil are advised to be cautious as they may encounter Funnel-webs in burrows at any time of the year.

Funnel-Web Spiders in Perth

The above locations are not common in Perth. Instead, these funnel-web spider locations and habitats are more available in other cities. In addition, the Western Australian Museum states that there are no true funnel-web spiders in the area.

Conclusion

The effects of a funnel-web spider bite include symptoms that may lead to the development of severe ones. The danger of its bite may impose risk to a victim’s life, especially if the venom flow is not controlled while an antivenom is not yet available. It may be done by applying a pressure immobilization bandage which is one of the skills that may be learned in a first aid course.

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