Most of us get a little excited when we see a big spider, but for the unfortunate few who fall victim to the bite of the daunting Brazilian wandering spider, that “excitement” takes on a whole new meaning: The venom of the wandering spider -- also known as the banana spider (or more formally Phoneutria nigriventer) causes erections in men.
“The venom of the P. nigriventer spider is a very rich mixture of several molecules,” says Dr. Kenia Nunes, a physiologist at the Medical College of Georgia who is currently studying the odd side effect. “These molecules are called toxins, and then we have various toxins in this venom with different activity. Because of this, when a human is bitten by this spider, we can observe many different symptoms including priapism, a condition in which the penis is continually erect.”
In addition to the hours-long painful erection, the wandering spider’s bite can cause loss of muscle control, severe pain, difficulty breathing and, if not treated, death, due to oxygen deprivation (with anti-venom, the victim usually recovers within a week.)
Luckily, deaths from this impressive creature – it boasts a leg span of four to five inches – aren’t all that common. According to a website maintained by Rod Crawford, curator of arachnids at the University of Washington’s Burke Museum, “authoritative sources state that over 7,000 authentic cases of human bites from these spiders have been recorded, with only around 10 known deaths.”
Usually found on banana plantations in the tropics, wandering spiders do tend to, uh, wander, though, with recent sightings reported at a Whole Foods in Tulsa, Oklahoma and an IGA store in Russell, Manitoba and a biting reported in Somerset, England in 2005.
But while the spider’s bite may be painful – or even deadly -- its oddball venom may actually prove to be a valuable asset when it comes to treating erectile dysfunction in men.
“In Brazil, we have several reports of human accidents involving this spider and priapism as a symptom,” says Nunes, who recently published a study in the Journal of Sexual Medicine on the spider venom and its potential use in treating ED. “So we started to investigate which part of the venom – which toxin – would be responsible for this symptom. We found the toxin responsible and performed experiments using hypertensive rats which have severe erectile dysfunction. The toxin was able to normalize the erectile function in these animals.”
After isolating the toxin (known as PnTx2-6), Nunes and her colleagues then studied the mechanism of action and found that the toxin acts in a different pathway as compared with other erectile dysfunction drugs, such as Viagra.
“This is good because we know that some patients don’t respond to the conventional therapy,” she says. “This could be an optional treatment for them.”
Does the Brazilian wandering spider venom hold any potential benefits for sexually dysfunctional women?
Nunes says she hasn’t performed any experiments “to investigate the action of this toxin in females yet,” but she intends to do it “soon.”