Most recently a family was forced to flee their south west London home after a egg sack of the spiders concealed in a bag of bananas hatched as mum tucked into a fruit. *Shudder.*
So what do we need to know about them? This is what:
The spider is of the genus <em>Phoneutria</em> – Greek for ‘murderess’. Makes sense.
Despite their name, they aren’t only found in Brazil – they’re native to South and Central America.
They are so named because they are typically found wandering across the jungle floor at night – presumably when the other spiders are safely tucked up in their beds.
Their bite is 30 times more deadly than that of the rattlesnake. So potent is their venom, <a href="http://www.guinnessworldrecords.com/world-records/10000/most-venomous-spider" target="_blank">just 0.006 mg (0.00000021 oz) is sufficient to kill a mouse.</a>
It is the presence of <a href="http://en.wikipedia.org/wiki/Phoneutria_nigriventer_toxin-3" target="_blank">PhTx3, a potent neurotoxin</a> makes the spider’s bite potentially lethal.
The Brazilian wandering spider <a href="http://www.guinnessworldrecords.com/world-records/10000/most-venomous-spider" target="_blank">can have a leg span of up to 17 cm. </a>
Bites are known to cause severe pain, breathing problems and paralysis. They are described as <a href="http://www.guinnessworldrecords.com/world-records/10000/most-venomous-spider" target="_blank">"large and highly aggressive creatures [who] often enter human dwellings and hide in clothing or shoes. When disturbed they bite furiously several times, and hundreds of accidents involving these species are reported annually."</a>
Milking for venom
An effective antivenom has been developed, known as <a href="http://en.wikipedia.org/wiki/Antivenom" target="_blank">Soro antiaracnidico</a>. Antivenom is typically created by milking venom from the desired spider, insect or snake (as illustrated) then diluted and injected into a horse, sheep or goat. The subject animal will undergo an immune response to the venom, producing antibodies against the venom's active molecule which can then be harvested from the animal's blood and used to treat envenomation. Internationally, antivenoms must conform to the standards of pharmacopoeia and the World Health Organization
A toxin from the venom – PnTx2-6 - boosts the availability of nitric oxide, a chemical that dilates blood vessels and increases blood flow. This means bites can lead to priapism – a persistent, usually painful erection. <a href="http://onlinelibrary.wiley.com/doi/10.1111/j.1743-6109.2012.02878.x/abstract" target="_blank">A study published last year in the Journal of Sexual Medicine suggests the toxin could be used to help treat erectile dysfunction in humans</a>.
A website maintained by Rod Crawford, curator of arachnids at the <a href="http://www.burkemuseum.org/spidermyth/myths/downunder.html" target="_blank">University of Washington’s Burke Museum</a>, maintains that deaths from Brazilian wandering spider bites are rare, with only 10 fatalities in more than 7,000 reported cases.