Oregon Poison Center Wants Your Spiders, Dead or Alive

Oregon Poison Center aims to determine which Northwest spiders bite.

A female hobo spider Photo courtesy: nps.gov

(PORTLAND, Ore. ) - The Oregon Poison Center at Oregon Health & Science University hopes to better understand spider bites in the Northwest by determining which spiders bite, which cause skin loss (ulcers), and specifically whether the much-maligned hobo spider does either.

Spider bites have been the subject of much folklore in medicine, but evidence directly linking spider bites to ulceration or infection is thin.

Often a person will see a red mark on their skin, see a spider nearby, and attribute the mark to the spider.

The Northwest native hobo spider has been implicated as a source of ulcers and skin infections for many years.

Its venom has been demonstrated to cause tissue death when injected into the skin of animals, but there is debate about whether the spider ever bites or is even capable of biting humans.

“There isn’t a single documented case of actually seeing a hobo spider bite a human that resulted in ulceration,” said Rob Hendrickson, M.D., study principal investigator, associate professor of emergency medicine and medical toxicologist. “However, the hobo spider has been presumed to be the only spider in the Northwest capable of causing ulceration.”

The Oregon Poison Center currently takes about 1,200 calls a year from Oregonians concerned about possible spider bites.

The center has decided to take the next step by asking all Oregonians who actually see a spider bite them to call 800-222-1222.

Poison center staff will offer medical advice as usual and then make follow-up calls during the next several weeks to check for signs of ulceration and infection.

The caller also will be sent a postage-paid package in which to send the spider to the poison center.

“We understand not everyone will feel comfortable killing the spider, and we won’t pressure them to do so, but we would still like to hear about the spider bite,” said Nathanael McKeown, D.O., study co-investigator, instructor in emergency medicine and fellow in medical toxicology, OHSU.

All spiders collected will be sent to a local expert in identifying Northwest spiders.

The species of spider will be linked with the description of the lesion to determine which spiders bite.