Spiders.us recognizes that many of our visitors have legitimate concerns about the risks of spiders biting them, other members of their families, or their pets. We take very seriously our responsibilities in addressing such matters. The following may help our audience to understand the problems we face in this regard and clarify the mission of our website.
Diagnosing Spider Bites
Even the medical community has difficulty diagnosing the cause of a mysterious wound. Symptoms of different maladies manifest themselves in different ways with different patients, so it is often extremely problematic to make a correct diagnosis. Rick Vetter of the University of California at Riverside conducted research that revealed at least fifty (50) causes of necrotic (tissue-destroying) wounds other than the bite of a brown recluse spider. His article can be accessed online here.
North American Spiders Known to be Dangerously Venomous
Only “widow spiders” (genus Latrodectus with five species) and “brown spiders” (genus Loxosceles with approximately 13 species) in the United States and Canada are proven to be potentially dangerous to people. Bites from these spiders are extremely rare and very, very few of them result in serious symptoms that require special medical treatment.
The “hobo spider,” Eratigena agrestis, is a European spider that has become established in the Pacific Northwest of the United States (and adjacent southern Canada). This species is not regarded as dangerously venomous in its native Europe, but there are persistent rumors that the bites of U.S. populations can cause necrotic wounds much like recluse spiders. This has not been reproduced in the laboratory, so there is no consensus on exactly what is going on here. However, the findings of recent research provide evidence that their venom is unlikely to be medically significant. McKeown et al. 2014 documented a verified hobo spider bite and the symptoms were fairly unremarkable. Also, research published in 2011 showed that the venom did not kill mammalian cells (was not necrotic) and that specimens exposed to MRSA did not transfer the bacteria; the research “confirms previous results and provides further evidence that the hobo spider is not a spider of medical concern” (Gaver-Wainwright et al. 2011).
Avoiding Spider Bites
Simple precautions can help you to easily avoid the potential for spider bites:
- Do not place your extremities (hands, feet) in places that you cannot see.
- Take care in moving items in and out of storage that have remained there for long periods.
- Do not leave shoes, gloves, hats, and clothing outside overnight. Nocturnal spiders may take refuge in such items at daybreak.
- Repair worn weatherstripping on doors to exclude wandering spiders.
- Mend holes in window screens to exclude climbing spiders.
- Seal all other openings in and out of the home such as where plumbing and electrical conduits enter or exit the house.
- Carefully inspect any objects coming indoors from outside (this includes houseplants, firewood, outdoor furniture, and toys), as spiders may hitchhike on such items. Exotic spiders can (rarely) stow away on fruits, vegetables, and tropical houseplants you purchase at the grocery. Be aware but not afraid.
- Do not handle spiders.
- Instruct children on how to recognize the potentially dangerous spider species in your area.
- Read our article on removing spiders from your home.