Spiders,
Spiders
Everywhere
There’s a new
venomous spider
to watch out for!
http://pep.wsu.edu/pdf/PLS116_1.pdf
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.
The rabbits
developed lesions
just like those he
had seen on
humans.
Hobo
spiders
could, in
fact, cause
necrotic
lesions.
http://pep.wsu.edu/pdf/PLS116_1.pdf
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
http://pep.wsu.edu/pdf/PLS116_1.pdf
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!!
http://egov.oregon.gov/ODA/PLANT/ippm_spider.shtml
http://www.washington.edu/burkemuseum/spid
ermyth/myths/insidewolf.html#
Giant House Spider
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.
Yellow Sac Spider
http://lancaster.unl.edu/enviro/pest/Articles/YellowSac
Spiders.htm
Symptoms:
Stinging sensation
Red sores with white pustules
Bite may blister and break
May feel mildly sick
Mexican Red Knee
Tarantula
http://www.museum.vic.gov.au/spidersparlour/tarant2.h
tm
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.
http://www.usq.edu.au/spider/find/spiders/507.htm
White-tailed Spider
Symptoms:
Burning pain
Swelling
Itchiness
4 days after bite
http://www.avru.unimelb.edu.au/avruweb/wtspage.htm
Black Widow
Symptoms:
Painful bite
Painful rigid abdomen
Severe diffuse muscle pain
Excessive salivation
Sweating
Nausea/vomiting
Difficulty breathing
Headaches
Weakness
http://muextension.missouri.edu/explore/wildthing/
images/blackwidow.jpg
Brown Recluse
Symptoms:
Necrotic lesions
Dizziness
Fever
Chills
Rash
Vomiting
http://www.uky.edu/Agriculture/Entomology/entfa
cts/struct/ef631.htm
Spider bite
http://www.lib.uiowa.edu/hardin/md/brownrecluse.html
http://www.uky.edu/Agriculture/Entomology/entfa
cts/struct/ef631.htm
Bacterial Infection
Where Do They Call Home?
Hobo Spider
Brown Recluse
Other Recluses
Map adapted from the following website:
http://www.uky.edu/Agriculture/Entomology/entfacts/struct/ef631.htm
Where Do They Call Home?
Tarantulas
Black Widow
Yellow Sac Spider
Map adapted from the following website:
http://www.uky.edu/Agriculture/Entomology/entfacts/struct/ef631.htm
What are the most dangerous
spiders in the world?
Redback Spider
Black Widows
Redback spider
http://faunanet.gov.au/wos/factfile.cfm?Fact_ID=82
Black Widow
http://muextension.missouri.edu/explore/wildthing/images/blackwidow.jpg
What are the most dangerous
spiders in the world?
Funnel-web spiders
Funnel-Web Spiders
http://www.avru.unimelb.edu.au/avruweb/Fws.htm
What are the most dangerous
spiders in the world?
Recluse
Spiders
Brown Recluse
http://www.uky.edu/Agriculture/Entomology/entfacts/struct/ef631.htm
What are the most dangerous
spiders in the world?
Banana Spiders
Banana Spider
http://www.rochedalss.qld.edu.au/wandering.htm
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.
http://spiders.ucr.edu/images/holplu1.jpeg
How should you protect
yourself?
• Shake out clothes and shoes before putting
them on.
• Inspect bedding (sheets/pillow cases)
before using.
• 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.