Lecture 12 - Dangerous Insects

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 • • • • • •

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) – – – – –

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 • • • • •

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} – – – –

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 – – – – –

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