ENTO 210 web Venoms allergens poisons STRAIN

Allergic Reactions

Definition

  • Allergic Reaction: An exaggerated immune response to a harmless substance.

  • Allergen: The substance that triggers the allergic reaction.

  • Involves histamine release leading to:

    • Inflammation

    • Increased blood flow

    • Nerve irritation (itching)

    • Contraction of airways (risk of anaphylaxis)

Types of Allergic Reactions

  1. Local Reaction:

    • Occurs at the site of allergen contact (e.g., mosquito bites, house dust).

    • Symptoms: Swelling, itchiness.

    • Treatment: Antihistamines, topical corticosteroids.

  2. Large Local Reaction:

    • Similar to local but extends beyond initial site.

    • Duration: Can last up to 10 days; onset ~12 hours post-exposure.

    • Treatment: Antihistamines, systemic steroids.

  3. Systemic Reaction:

    • Allergens spread via blood/lymph; leads to anaphylaxis.

    • Symptoms: Trouble breathing, drop in blood pressure, risk of anaphylactic shock.

    • Risk increases with previous exposure.

Symptoms of Anaphylaxis

  • Possible Symptoms:

    • Apprehension, weakness, itching, rash, swelling.

    • Gastrointestinal issues: cramps, diarrhea, vomiting.

    • Respiratory issues: chest tightness, wheezing, difficulty breathing.

    • Cardiovascular symptoms: dizziness, lightheadedness, low blood pressure.

Treatment for Anaphylaxis

  • Epinephrine: First-line treatment for severe allergic reactions.

    • Administration:

      • "Orange to the thigh, white to the sky" (emphasizing correct injection).

    • Post-administration care: Hospitalization for IV treatments, antihistamines, corticosteroids.

    • Severe reactions can be fatal within minutes without treatment.

Arthropods Causing Allergies

Blood-Feeding Arthropods

  • Examples: Mosquitoes.

    • Inject saliva compounds to prevent clotting; may cause local allergic reactions.

Venomous Arthropods

  • Examples: Bees, wasps, ants, spiders, scorpions.

    • Higher potential for anaphylaxis due to venom reactions.

Other Allergens

  • Dust Mites: Can cause respiratory allergies when inhaled.

  • Ingested Arthropods: E.g., mealworms can lead to gastrointestinal symptoms.

FDA Regulations

  • Forensic entomologist perspective on insect parts in food:

    • Frozen berries allowed: 4+ larval parts per 500 grams, 10+ whole insects (excluding certain bugs).

    • Flour allowed: 75+ insect fragments per 50 grams.

Definitions

  • Toxin: Venom or poison causing illness at low concentrations.

  • Venom: A type of toxin injected via bite/sting.

  • Poison: A type of toxin absorbed by the body.

Venomous Arthropods

Centipedes

  • Family: Scolopendridae.

  • Venomous bite, typically non-fatal but can cause severe pain.

Spiders

  • Brown Recluse: Causes necrotic lesions, invasive thrombosis (Loxosceles reclusa).

  • Widow Spiders: Neurologic venom; more systemic risks, antivenom available.

Hymenopterans (Stinging Arthropods)

  • Queens lay eggs; workers do not, but they sting. Examples include:

    • Bees: Die after a sting due to barbed stingers.

    • Wasps: Can sting repeatedly.

    • Notable Species: Yellow jackets (release pheromones to attract more stingers), Africanized honeybees.

Scorpions

  • Example: Arizona bark scorpion, notably venomous in the U.S.

Poisonous Arthropods

  • Millipedes: Secretions cause irritation.

  • Caterpillars: E.g., Pus Caterpillar can cause severe adverse effects.

  • Blister Beetles: Catharidin causes blisters and can lead to serious health risks if ingested.

Case Study: Detecting Anaphylaxis Post-Mortem

  • Investigated a death allegedly caused by bee swarming:

    • No external signs during autopsy.

    • Elevated tryptase and troponin levels confirmed anaphylaxis.

    • Positive allergen-specific immunoglobulin test for Vespula species (yellow jacket).

    • Importance of biochemical markers in forensic analysis.

Conclusion

  • Acknowledgment of the interconnectedness between entomology and human health regarding allergies and poisonings.