5 animal toxins

Question 1

are poisonous animal toxins defensive?

Answer 1

-use their toxins for defense
-no real delivery mechanism

Question 2

are venomous animal toxins defensive?

Answer 2

-have a means to deliver toxins sometimes in a regulated way- their venom

Question 3

what are cane toads?

Answer 3

-a large, warty beast that secretes a variety of poisonous substances from its parotid glands, intended to discourage things from eating it
-bufo toad secretions have been used by many cultures as traditional medicines and in ritualistic ceremonies
-were introduced into Hawaii, Florida, Australia, Puerto Rico, Venezuela, the Philippines, etc. to control insects in sugar cane crops (very big mistake)

Question 4

what are the clinical effects of cane toad poisoning?

Answer 4

-the clinically most significant toxins are cardiotoxins, like the digitoxins found in plants. people have died 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

Question 5

what is fugu poisoning?

Answer 5

-pufferfish (and related species; fugu) are a delicacy in Japan, but a risky one
-certain parts of the fish (gonads, skin, intestines, liver) contain tetrodotoxin in fatal concentrations
-specially trained fugu chefs learn to remove almost all the toxin, leaving just enough to give diners a thrill

Question 6

how does tetrodoxin work?

Answer 6

-blocks sodium channels in peripheral nerves and muscles, preventing transmission of the action potential
-just a bit can cause death from respiratory paralysis in minutes, and mortality rate is >50% even today

Question 7

what is the treatment for tetrodotoxin?

Answer 7

includes respiratory and cardiovascular support
-there is no antitoxin. get the fish out (but dont make them vomit)

Question 8

what is paralytic shellfish poisoning?

Answer 8

the most deadly disease associated with “harmful algal blooms”
-poisoning occurs when people eat shellfish which have accumulated saxitoxin in their edible bits
-this happens when the shellfish feed on tiny marine alga (dinoflagellates) which produce the toxin

Question 9

what is saxitoxin?

Answer 9

-acts just like tetrodotoxin, blocking sodium channels in the peripheral nerves and muscles, preventing transmission of the action potential
-just a bite can cause death from respiratory paralysis in minutes

Question 10

are some animal toxins offensive?

Answer 10

-not all creepy crawlies are out to get us: attacks on humans are still largely defensive
-no real delivery mechanism
-venomous animals have a means to delivery sometimes in a regulated way (their venom)

Question 11

what does it take to be venomous?

Answer 11

-a venom gland to make the venom
-a venom apparatus to inject the venom (fangs or a stinger)

Question 12

what is the box jellyfish?

Answer 12

-the venom of australian box-jellyfish is amongst 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, 60-foot tentacles lined with hundreds of thousands of nematocysts
-the death toll is >60

Question 13

what is the venom apparatus of a nematocyst?

Answer 13

-nematocysts are microscopic harpoons triggered by mechanical or chemical stimulation
-they are fast enough to kill a passing fish (milliseconds) and penetrate the scaliest skin, easily, embedding and discharging venom

Question 14

what are the clinical effects of envenomation of nematocysts?

Answer 14

-venom causes immediate severe pain, local tissue death (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

Question 15

what is nematocyst harvesting?

Answer 15

-some nudibranchs (sea slugs) are able to harvest nematocysts from the sea anemones and corals they eat
-the nematocysts pass untriggered and intact thru the digestive system of the slug and are accumulated in the ‘tentacles’ as a defensive mechanism

Question 16

what happened when wasps killed mayor of quebec town?

Answer 16

-Lucie Roussel, mayor of La Prairie, died on july 20th 1024, after being stung about 15 times by wasps after stepping on a nest
-the 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

Question 17

what are the clinical effects of envenomation of wasps?

Answer 17

-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 failure
-carry 2 epipens

Question 18

do wasps want to sting me?

Answer 18

-bumble bees and honey bees are mostly docile but not africanized ‘killer bees’, they will chase you for miles
-most wasps and hornets just want to be left alone, but yellowjackets can be aggressive

Question 19

what is the invasion of the killer bees?

Answer 19

-attempts were made to increase honey production in Brazil
-breeding of african bees with european bees
-african bees escaped and hybridized with wild european bees
-hybrid is must more aggressive and defensive

Question 20

what is arachnophobia?

Answer 20

fear of spiders
-afflicts 20-25% of canadians

Question 21

what are sydney funnel-web spiders?

Answer 21

-these spiders are often considered the most venomous in the world
-the potent neurotoxin Robustoxin binds sodium ion channels in nerves and slows their closing (repetitive firing)

Question 22

what are the symptoms of robustoxin?

Answer 22

appear in minutes
-pain, hypotension, dyspnea, muscle twitching, pulmonary edema, circulatory and respiratory failure (death in <30 minutes)

Question 23

what is the venom apparatus (chelicerae) and clinical effects of envenomation of sydney spiders?

Answer 23

-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 produce one dose of antivenom

Question 24

how do we make antivenom?

Answer 24

Question 25

what is cobra venom?

Answer 25

-the venom of elapid snakes is mostly neurotoxic and may have multiple targets, including ion channels, neuro-transmitter receptors and acetylecholinesterase

Question 26

what are the clinical effects and treatment of cobra venom?

Answer 26

-effects include slurred speech, difficulty swallowing, droopy eyelids (all within an hour), and progressive muscle weakness and paralysis leading to respiratory failure
-treatment includes respiratory and cardiovascular support, and especially/quickly antivenom

Question 27

what about rattlesnakes?

Answer 27

-prairie rattlesnakes, like all viperid snakes, have a very effective venom apparatus
-fangs are hinged for deeper penetration

Question 28

what are the clinical effects of rattlesnakes?

Answer 28

-major clinical effect include pain, local tissue necrosis, bleeding, shock, kidney failure, pulmonary edema and respiratory failure
-they tend to be less toxic than elapid or hydrophid venoms and act mainly on the vascular system, interfering with coagulation and capillary membrane integrity and are highly cytotoxic

Question 29

what are the treatments for rattlesnake venom?

Answer 29

-not doing anything stupid, 25% of bites are “dry”, so dont panic
-do not use a tourniquet, do not cut and suck
-immobilize the bite site and get to the hospital (or veterinary clinic)
-key aspects of treatment include IV fluids for shock, control bleeding, control pain, respiratory and cardiovascular support and especially antivenom

Question 30

what are defensive sea creatures?

Answer 30

-these species are notorious for possessing the most potent venom among fish, which is an injectable toxin housed within twin glands associated with the 13 hypodermic needle-like spines on the animal’s back
-venom is DEFENSIVE

Question 31

what is envenomation of defensive sea creatures?

Answer 31

-envenomation can cause a diverse range of symptom, including excruciating pain, paralysis, cardiac arrest and death

Question 32

what is an example of a defensive sea creature?

Answer 32

-the venom of stonefish is stored in the dorsal fin spines and contains a proteinaceous toxin, verrucotoxin (VTX) among other things
-lionfish

Question 33

what are offensive sea creatures?

Answer 33

-venom primarily for food acquisition
-can be used defensively if needed
-avoid any contact (the venoms are really nasty)
-death can occur within minutes to hours

Question 34

what are examples of offensive sea creatures?

Answer 34

-blue ringed octopus
-cone snails
-sea snake

Question 35

what about mammals?

Answer 35

not so much
-draculin: anticlotting agent and various other vasodilation and clot dissolving compounds to keep blood flowing
-some shrews

Question 36

what about birds?

Answer 36

even less
-batrachotoxin (BTX) is an extremely potent cardiotoxic and neurotoxic steroidal alkaloid found in certain species of beetles, birds and frogs
-these birds and frogs do not synthesize toxins but accumulate them from their diet

Question 37

what is the conclusion?

Answer 37

-animal ‘poison’ most developed in invertebrates and reptiles
-poisons seems to have been lost during the evolution of higher animals
-some higher animals utilize the poisons of other species, mainly for defense
-animal venoms are usually complex mixtures of compounds aimed at different target organs of the victim