Pest, Plagues & Politics
Lecture 12
Dangerous Insects
Yes, it is true!!
Some insects can hurt you!!!
Stinging Rose
caterpillar
Key Points
• Modes of Action
• Venomous Hymenoptera
• Wasp vs. Bee vs. Ant
• Allergic vs. toxic response
• Anaphylaxis
• Other Families of dangerous
insects
• Psychological Aspects
Cantharidin
• Poisonous chemical secreted by
the blister beetle
Dangerous Insects
Modes of Action
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•
•
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Bites
Stings
Allergies
Dermatitis
Myiasis
Psychological Disorders
Dangerous Insects
• Mortality
– 40 to 100 deaths annually in the U.S.
• Date Rate (per 1,000,000 people)
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Stinging Insects
Alcohol related
Handgun related
Lightning
Scholastic football
0.20
500
85
0.50
0.12
Insects vs. Arachnids
Arachnid venom can be toxic enough to kill
with a single envenomation
one bite = one death
With insect venom, death is “usually” caused by an
over reaction of the immune system.
Poisonous Spiders in Oregon
• The black widow
• The yellow (or gold) sac spider
• The hobo spider (aggressive house spider)
The brown recluse
does not naturally
occur in the PNW.
Black Widow
Hobo Spider
Hobo spider bite – mildly venomous – often necrotic
Brown Recluse
Camel Spider – a Solipugid {not a real spider}
Venomous Hymenoptera
• Mass envenomation
– LD50 of honey bee venom = 1,000 stings
– Toxicity of honey bee venom  eastern
diamond back rattle snake.
– Who is going to stick around to get one
thousand stings??
Honey Bee Stinger
Hornet
Stinger
NO Barbs
Venomous Hymenoptera
• Ant Venom
– family Formicidae
• offense-defense-communication
• Wasp Venom
– multiple families
• prey capture - defense
• Bee Venom
– multiple families
• defense only
The Red Imported Fire Ant – Solenopsis invicta
Dangerous Hymenoptera
• Toxic vs. Allergic Response
Toxic
– results from multiple stings
– sometimes difficult to distinguish from an
allergic response
– Symptoms
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•
•
•
•
gastrointestinal dysfunction
fainting
muscle spasms
convulsions
et alia
Dangerous Hymenoptera
• Allergic Reaction
– an altered sensitivity due to a previous
exposure to the venom
– 0.08% of the general population
– Are You of this small minority??
• Find Out!!!!
• Get treatment!!!!
The Allergic Response
• Normal
{note: everyone is allergic}
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it hurts!!
Pain lasts a variable period
Accompanied by the appearance of a wheal
Soreness & itching which usually persists for
24 to 48 hours.
The Allergic Response
• Large Local Reaction
– swelling at the sting site & beyond over a 4
to 12 hour period
– persists for more than 48 hours
– soreness & itching can be severe
– not Fun
– but not overly serious from a medical
standpoint.
The Allergic Response
• Systemic Reaction
– Deserves serious medical concern
– Potentially life threatening
– Body responds to the sting in areas far
removed from envenomation site.
– Anaphylaxis can result
ANAPHALAXIS
• Cutaneous
– rashes-swelling-hives on various parts of the
body
• Vascular
– dizziness, fainting & unconsciousness
• Respiratory
– difficulty breathing, constrictions in throat
• Misc.
– chills, fever, anxiety, incontinence
ANAPHALAXIS
• Medical Emergency
– 58% of deaths occur within one hour of sting
– 75% of deaths occur within six hours of sting
• Treatment
– EPINEPHRINE (adrenaline)
– Causes vasoconstriction, which counteracts
the vasodilatation properties of venom
Treatment
• Currently two systems
– ANA-KIT
– EPIPEN
– both are sub-epidermal injections of premeasured doses of adrenaline
• Requires a prescription to obtain
• Oregon law allows persons other than
physicians to administer.
Immunotherapy
• Is all the trauma necessary??
NO!!
• Desensitization is effective ca. 95% of the
time.
ERUCISM
• Etymology
– Latin ‘eruca’ = caterpillar
• Envenomation by toxic setae of caterpillars
Puss moth caterpillar
Hickory Tussock Moth caterpillar
ERUCISM
Io Moth
ERUCISM
Saddleback
caterpillar
Sibine stimuli
A Saturnine
moth common
to the east side
of Oregon
LEPIDOPTERISM
• An allergic response triggered by the
wing scales of any number of moths &/or
butterflies.
• Expressed by respiratory distress.
Hemiptera
• Some formidable biters in several
families
• Assassin Bugs
– family Reduviidae
– Predaceous on
other insects
– utilize extra-oral
digestions
• enzymes injected into the food/prey item
• a fine line between venom & digestive enzymes
Rhodnius prolixus dining
Coleoptera
• Bombardier Beetles
– family Carabidae
– When disturbed release a hot-toxic spray of
quinones & H2O2 at temperatures of 100°
C.
Psychological Aspects
• Entomophobia
– a morbid, irrational fear of, or aversion to
insects.
– Most deeply manifested
by the condition of
delusional parasitosis
Delusional Parasitosis
• Perceived to be “infested” with insects
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in or under the skin
around or just inside body openings
in sputum
internally, particularly the stomach or intestines
in the vicinity of the sufferer, particularly in the home
• Use of home remedies
• Self exposure to often dangerous levels of
insecticides.
Delusional Parasitosis
• SYMPTOMS
– a long time sufferer
– seen by numerous physicians, exterminators,
parasitologists, hygienists & entomologists
– fiercely rejects negative findings
– exhibits the “matchbox sign”
• delivers or mails containers with “bugs”
• samples consist of anything but “bugs”
– self-mutilation can occur
Key Points
• Modes of Action
• Venomous Hymenoptera
• Wasp vs. Bee vs. Ant
• Allergic vs. toxic response
• Anaphylaxis
• Other Families of dangerous
insects
• Psychological Aspects