Venom and Toxins Flashcards
Which snake is the most toxic, and which is the most lethal? Is there a difference between them? Why?
Most toxic: Inland taipan, has the smallest LD50
Most lethal: Black Mamba. Has a combined force of its small LD50, high venom yield and agressiveness.
Why is the first symptom of a snake bite blurred vision?
Because the intraocular muscles of the eye become flaccid.
Death from snake bites most commonly occurs from?
Respiratory paralysis
Why do snake procoagulants result in bleeding? What can this lead to?
They deplete fibrinogen/fibrin, causing a loss of clotting factors, making the patient unable to clot.
Can lead to intracranial bleeding.
Strong coagulopathy is found in which snake?
Brown snake
Myotoxicity in snakebites is due to what? What might be noticed in a patient with myotoxicity?
It is due to myotoxic PLA2 enzymes.
Causes myoglobinuria.
Elapids commonly have what kind of neurotoxin?
Postsynaptic
What is the name of the technique employed in the first-aid treatment of snake bites?
The sutherland pressure immobilisation technique.
What is the main group of snakes in Australia?
Elapidae
How are antivenoms produced?
From hyperimmunised horses that produce IgG.
presynaptic neurotoxins are also called?
Beta-neurotoxins, SPANs, or Snake sPLA2 neurotoxins.
Which types of snake neurotoxins have a poor response to antivenom therapy?
Presynaptic neurotoxins.
Strong post-neurotoxicity is found in which snake?
Death Adder
Which venemous/toxic animal is responsible for the most deaths?
Snakes
True or false, animals use venom for defence or offence.
False. They can use it for both in some cases, e.g. scorpions.
Which venemous/toxic animal is responsible for the most hospitalisations?
Hornets, wasps and bees.
What is the animal with the most rapid fatal envenomation in the world?
The box jellyfish.
How many bee stings have to occur for a person without an allergy to die?
~300
Strong myopathy and pre-neurotoxicity is found in which snake?
Tiger snake
Generalised reactions if they occur usually happen the first time the person is stung. True or false?
False.
It is more common that they have a mild reaction the first time.
How long does presynaptic paralysis usually take to manifest in a patient?
1-2 hours.
What are the symptoms of a funnel-web spider bite?
Pain, hypertension, dysponea, muscle fasiculations, salivation, lachrymation.
Name five toxic animals relevant to Australia.
- Sydney Funnel Web Spider
- Blue Ringed Octopus
- Inland Taipan
- Stonefish
- Box Jellyfish
What are the names and alphanumeric code-names of the two primate active toxins from the Sydney Funnel Web spider?
Robustotoxin (Hv1A)
Versutoxin (Ar1A)
How many snake bites occur in Australia per year and how many of those require antivenom?
1000-3000 bites/year
100-500 require antivenom
What is the physiogical effect of a funnel web spider’s bite?
It causes slowed inactivation of the voltage-gated sodium channel, leading to uncontrolled neurotransmitter release and concomitantly muscle fasiculations and ANS symptoms.
Presynaptic neurotoxins act how?
By disrupting vesicle release and vesicle recycling.
Box jellyfish have a coiled barb mechanism for deploying venom, what is it called? Also, how many are there per mm2 on the average tentacle?
Nematocyst. There are approximately 1500 of them per mm2.
What percentage of elapids carry enough venom to kill?
25%
There are 80 elapid species and 20 of them with enough venom to kill.
Which is more potent, postsynaptic neurotoxins or presynaptic neurotoxins?
Presynaptic
Post-synaptic neurotoxins are also called?
Alpha neurotoxins, or
Three fingered toxins
What is the difference between venemous and poisonous animals?
Poisonous animals have no mechanism for delivery.
Venemous animals can deliver poison via biting or stinging act.
Which has a quicker time of onset, presynaptic or postsynaptic neurotoxins?
Postsynaptic
A typical example of a PLA2 neurotoxin is?
Notexin or ß-Bungarotoxin
Strong pre-neurotoxicity is found in which snake?
Taipan
Strong myotoxicity is found in which snake?
Mulga Snake
Snake neurotoxins usually cause rigid or flaccid paralysis?
Flaccid
Which snake is the most toxic, and which is the most lethal? Is there a difference between them? Why?
Most toxic: Inland taipan, has the smallest LD50
Most lethal: Black Mamba. Has a combined force of its small LD50, high venom yield and agressiveness.
Why do snake procoagulants result in bleeding? What can this lead to?
They deplete fibrinogen/fibrin, causing a loss of clotting factors, making the patient unable to clot.
Can lead to intracranial bleeding.
Generalised reactions if they occur usually happen the first time the person is stung. True or false?
False.
It is more common that they have a mild reaction the first time.
What is the physiogical effect of a funnel web spider’s bite?
It causes slowed inactivation of the voltage-gated sodium channel, leading to uncontrolled neurotransmitter release and concomitantly muscle fasiculations and ANS symptoms.
