<~~ BACK to PJC ZooTech

Venom and Antivenom

Herpetoculture

Pensacola Jr College

Types of Venomous Snakes

w    Aglyph

w    Opisthoglyph

w    Proteroglyph

w    Solenoglyph

1. Aglyphs

w    Homodont maxillary teeth

w    No venom

w    Boids, pythons, most colubrids

Python skull

Tree Python (an aglyph)

Mole Snake skull (aglyph)

2. Opisthoglyphs

w    No hollow fangs, enlarged rear teeth with or without grooves

w    Venom -- Duvernoy’s gland

•    Immobilizes prey

•    Aids digestion

•    Small volume delivered slowly

•    Usually not toxic to humans

w    A few colubrids

Boomslang skull (opisthoglyph)

Sandsnake (opisthoglyph)

3. Proteroglyphs

w    Long maxilla with single pair of hollow fixed fangs, other teeth behind

w    Small venom glands:

•    Highly concentrated neurotoxic venom

•    Instant prey paralization

w    Adapted for elongated prey

w    Elapids

Cobra skull (proteroglyph)

Mamba (proteroglyph)

4. Solenoglyphs

w    Maxilla extremely reduced, rotates on prefrontal, and has one pair of hollow fangs

w    Huge venom glands:

•    Slower acting venom, usually hemotoxic

•    Large muscles for injection

w    Adapted for high weight prey

w    vipers

Puff Adder skull (solenoglyph)

Gland and Hollow Fang

Desert Viper (solenoglyph)

Snake Venom

w    Made up of approx. 20 different proteins / enzymes

w    Each species usually has 6 – 12 of these enzymes

w    Types and amounts of enzymes present determine:

•    Toxicity level of snake

•    Hemotoxic vs. neurotoxic

Venom Enzymes

Types of Venom

w    Neurotoxin

w    Hemotoxin

1. Neurotoxin

w    Lots of short proteins

w    Goes directly into nervous system and blocks neuromuscular transmission (pain reduction)

w    Victim paralyzed

w    Respiratory system and heart function shut down

2. Hemotoxin

w    Lots of enzymes that break down other proteins (extremely painful)

w    Digestion of body tissues

w    Often causes blood clotting OR acts as anticoagulent

w    Slow acting

Antivenom / Antivenin

w    Antibodies against the venom, to fight its effects

Obtaining Antivenom

w    Milk snakes of their venom

w    Inject increasing amounts of the venom into horses or sheep (primarily Percherons)

w    Collect blood from them

w    Extract the serum from blood

w    Concentrate the antivenom

Milking a Snake

Antivenom Types:

w    Monovalent antivenom

w    Polyvalent antivenom

1. Monovalent antivenom

w    Obtained using venom from one species of snake

w    May be applicable against venom of closely related species

w    More effective

2. Polyvalent antivenom

w    Obtained using venom from a variety of snakes within a region

w    May be applicable against venom of any snake from that region within a venom type

w    Less effective

Using Antivenom

w    Premedicate patient with adrenaline, subcutaneous

w    Antivenom diluted (usually 1 to 10) and given I.V.

w    Watch for allergic reactions

•    Antihistamine and steroids given for reactions

w    Prednisone for 5 days to prevent serum sickness

How much antivenom?

w    Quantity does NOT vary by patient (sex, age, weight, etc)

w    Quantity dependent on:

•    Type of snake

•    Amount of venom injected

w    Minimal evenomation may be better without antivenom

Online Bite Protocols

w    http://www-surgery.ucsd.edu/ent/DAVIDSON/Snake/proinde.htm

 

Venomous Snake Handling

w    Snake hook / field hook

w    Snake tongs or clamps

w    Head block

w    Clear cast acrylic tubing

Snake hook

Pilstrom Tongs

Acrylic Tubing