Q 1: Poisons and venoms Flashcards
the box jelly fish
The venom of Australian box-jellyfish (Chironex fleckeri) is among the most potent of any animal. They are fast swimmers (5 ft/sec), active hunters, and congregate in shallow water near shore. They have about 60, 6-foot tentacles lined with hundreds of thousands of nematocysts.
what are nematocyst
Nematocysts are microscopic harpoons triggered by mechanical or chemical stimulation. They fire fast enough to kill a passing fish (milliseconds), and penetrate the scaliest skin easily, embedding and discharging venom.
what are the clinical effects of envenomation
Venom causes immediate, severe pain, local tissue necrosis, breakdown of RBCs, fluid in the lungs (pulmonary edema), respiratory arrest and heart failure. Death from cardiac arrest usually happens within minutes with a fatal envenomation. Antivenom treatment must be immediate to be useful.
what is the cane toad
The cane toad (Bufo marinus) is a large, warty beast that secretes a variety of poisonous substances from its parotid glands, intended to discourage eating.
Bufo toad secretions have been used by many cultures as traditional medicines and in ritualistic ceremonies.
Cane toads were introduced into Hawaii, Florida, Australia, Puerto Rico, Venezuela, the Philippines, etc., as a biological control agent (very big mistake).
Clinical Effects of Poisoning from the cane toad
The clinically most significant toxins are cardiotoxins, like the digitoxins found in plants. People have died (usually those seeking the aphrodisiac or hallucinogenic thrills), but the big problem is wild predators and dogs. Signs include hypersalivation, weakness, slow heart rate, hypotension, pulmonary edema, respiratory distress, coma, heart failure and death. Treatment is supportive, plus anti-digitalis antibodies (Digibind®).
who is lucie roussel
Lucie Roussel , mayor of La Prairie, died on July 20, 2014 after being stung about 15 times by wasps after stepping on a nest. That level of envenomation would not be lethal except in the case of a severe allergic reaction.
2 – 4% of people are allergic, but many are not aware of it.
Clinical Effects of Envenomation from stings (wasps)
venom is a complex mixture, but most stings only cause localized pain, irritation and swelling.
It takes hundreds of stings to be lethal by direct toxicity, but only 2 if hypersensitive. Severe reactions (anaphylaxis) cause hypotension, shock and respiratory distress.
Carry 2 EpiPens®.
what is the most dangerous venomous animal in canada in canada
wasps-bees, hornet -dangerous is defined by the body numbers
Sydney Funnel-Web Spiders
These spiders (Atrax robustus), are often considered (with South America banana spiders) the most venomous in the world. The potent neurotoxin Robustoxin binds sodium ion channels in nerves and slows their closing → repetitive firing. Symptoms appear in minutes: pain, hypotension, dyspnea, muscle twitching, pulmonary edema, circulatory and respiratory failure → death in
what is the chelicerae
Venom Apparatus (chelicerae) and Clinical Effects of Envenomation The massive fangs of the male spider can easily penetrate human skin. Treatment is supportive, aimed at maintaining CV and respiratory function. Many deaths were reported before the development of Atrax antivenom in 1981.
No one has died since, but stocks may be running low. You have to milk 70 spiders to get one dose of antivenom.
what is robustoxin
The potent neurotoxin Robustoxin binds sodium ion channels in nerves and slows their closing → repetitive firing.
how to make anti venom
collect a spider-venom is injected in a bunny to immunize it- blood is collected from the bunny- and allowed to clot then they remove unwanted substances and get just the antibodies
The Suicide of Cleopatra Queen of Egypt
Last Ptolemaic ruler of Egypt, mistress of Julius Caesar and Mark Antony. They were defeated by Augustus in 31 BC. She committed suicide by holding venomous snakes to her breasts rather than submit.
Legend says she used Egyptian cobras (Naja haje), effective and available.
what are the clinical effects of cobra venom
The venom of Elapid snakes is mostly neurotoxic and may have multiple targets, including ion channels (pre- and post-synaptic), neuro-transmitter receptors, and acetylcholinesterase.
Effects include slurred speech, difficulty swallowing, droopy eyelids (all within an hour), and progressive muscle weakness and paralysis leading to respiratory failure.
how many ppl died from snake bites a year
100 000
