Presentation on theme: "Spiders, Spiders Everywhere There’s a new venomous spider to watch out for!"— Presentation transcript:
Spiders, Spiders Everywhere There’s a new venomous spider to watch out for!
Case Report #1 56 year old woman feels bite on thigh Nausea, migraine-like headache In few days, necrotic tissue sloughs off 2 weeks later she seeks medical attention Bleeding from nose, ears, etc. Information taken from an article written by Gordon Grice, September 2005, Bite of the Hobo SpiderIs it arachnophobia or are people dying? DISCOVER Vol. 26 No. 09.
Was it a spider that made her sick? Darwin Vest, toxinologist The first to investigate the cause of the lesions. He collected spiders from houses where humans had developed lesions or had symptoms similar to the woman who died. He collected the venom and placed it on the backs of rabbits. Hobo spiders could, in fact, cause necrotic lesions. The rabbits developed lesions just like those he had seen on humans.
Prime Suspect Hobo Spider Genus, species: Tegenaria agrestis Family: Agelenidae Nicknamed: “mat weaver” Common in Europe, entered US in the 1930s, attached egg sacs to shipments
Hobo Spider Symptoms: Blistering wound ringed with yellow (moon in a halo of smog) Headaches Disturbed thinking (rare) Image of a finger with a wound caused by the Hobo spider…OUCH!!
Giant House Spider ermyth/myths/insidewolf.html# HELPFUL to humans The Hobo spider’s cousin Preys on the Hobo spider LARGE HAIRY SPIDER DOES NOT EQUAL WOLF SPIDER GHS commonly mistaken for a Wolf spider. Classification based on arrangement of eyes.
Spiders.htm Yellow Sac Spider Symptoms: Stinging sensation Red sores with white pustules Bite may blister and break May feel mildly sick
tm Mexican Red Knee Tarantula Symptoms: Venom is relatively harmless to humans. The bite is similar to a bee or wasp sting. If their hairs poke your skin, they can cause a rash, redness and itchiness. Allergic reactions are unusual.
White-tailed Spider 4 days after bite Symptoms: Burning pain Swelling Itchiness
Where Do They Call Home? Map adapted from the following website: Hobo Spider Brown Recluse Other Recluses
Where Do They Call Home? Map adapted from the following website: Tarantulas Black Widow Yellow Sac Spider
What are the most dangerous spiders in the world? Redback Spider Black Widows Redback spider Black Widow
What are the most dangerous spiders in the world? Funnel-web spiders Funnel-Web Spiders
What are the most dangerous spiders in the world? Recluse Spiders Brown Recluse
What are the most dangerous spiders in the world? Banana Spiders Banana Spider
Are daddy long legs the deadliest spider? Nah, that is a myth! This myth may have been started because daddy long legs actually prey one of the more dangerous spiders, the Australian Redback Spider.
How should you protect yourself? Inspect bedding (sheets/pillow cases) before using. Shake out clothes and shoes before putting them on. Bedspreads and bedskirts are potential risks – contact with the floor. Be careful around woodpiles, rock piles, etc. Pesticides should be a last resort or if there is a heavy infestation.
Questions? Why is it difficult for a doctor to correctly diagnose spider bites? Why do you think it would be unwise to use pesticides for spider control?
Questions? Why is it difficult for a doctor to correctly diagnose spider bites? –They oftentimes look like another disease such as a rash, bacterial infection, or even diseases like diabetes. Why do you think it would be unwise to use pesticides for spider control? –You kill not only the bad spiders, but you also take out a natural predator of the bad spider (wolf spiders, giant house spiders do a great job of keeping insect populations and spider populations in check.