What Is a Blue-Ringed Octopus, and How Does It Bite?
Picture of a blue-ringed octopus
- The blue-ringed octopus, a cephalopod, is less than 8 inches in diameter with its tentacles extended. It has blue rings and luminous tentacles. It is found in the Indo-Pacific Ocean area (Australia, New Zealand, New Guinea, and Japan). The blue-ringed octopus is not an aggressive marine animal.
- Cephalopods, a name used to refer to all octopi, usually live in rocky ocean bottoms. The blue-ringed octopus lives in rock pools, under shells, and in shallow waters, making them a risk to people wading in tide pools, children, and divers alike. They are rarely seen in water deeper than 10 feet.
- When at rest, the octopus has dark brown to yellow bands over the body with superimposed blue patches or rings. When excited or angered, the body darkens and the blue circles or stripes glow iridescent blue.
- The blue-ringed octopus does not release inky fluid like other octopi are able to do.
- When human contact with a blue-ringed octopus occurs, it is usually accidental. Avoid handling this octopus because its sting contains tetrodotoxin, which paralyzes the victim (similar to pufferfish poisoning). The sting is often fatal.
- The blue-ringed octopus injects its toxin by biting. The venom is held in salivary glands and the mouth of the octopus in on the underneath side in the middle of the body.
- Since the blue-ringed octopus is not an aggressive marine animal, most cases of bites are from a person picking up and handling the octopus, or stepping on it in a sandy beach area. To avoid being bitten by a blue-ring octopus, never pick up or handle this marine animal, and when entering the ocean, shuffle your feet as you enter to avoid stepping on the octopus.
What Are the Signs and Symptoms of Blue-Ringed Octopus Bite?
The blue-ringed octopus bite is highly poisonous to humans. If you or someone you know has been bitten by a blue-ringed octopus, call 911 or activate the local medical emergency service in the area immediately.
- Most bites cause minimal pain for the first 5-10 minutes then begin to throb and may get numb and involve the rest of the arm (or extremity) bitten.
- Bleeding may be excessive
- Numbness, nausea, vomiting, changes in vision, and difficulty swallowing.
- After approximately 10 minutes, the victim may have difficulty breathing, become paralyzed, and require artificial ventilation until they can be transported to a hospital. This is often preceded by numbness or loss of feeling around the lips and mouth. If medical care is not provided immediately, respiratory failure may occur, which may lead to cardiac arrest and death.
What Is the Treatment for a Blue-Ringed Octopus Bite?
Blue-ringed octopus bites are considered a medical emergency so do not wait for symptoms to develop; quickly get the person bitten out of the water and, if possible, call 911 and consider transport to the nearest hospital.
- Use the pressure immobilization technique: The duration of life-threatening symptoms is usually from 4 to 10 hours. After that time, surviving patients typically show rapid signs of improvement.
- Use an elastic bandage (similar to ACE bandage) to wrap the limb starting at the distal end (fingers or toes) and wrap toward the body. It should be tight, but the fingers and toes should remain pink so that the circulation is not cut off.
- The extremity should also be immobilized with a splint or stick of some sort to prevent it from bending at the joint(s).
- The elastic bandage should be removed for 90 seconds every 10 minutes and then reapplied for the first 4-6 hours. (Hopefully, medical care can be received within this time period.)
- If 30 minutes or more have passed since the blue-octopus bite, the pressure immobilization technique is not likely to be helpful.
- If the patient is having difficulty breathing, assist with mouth-to-mouth ventilation.
- Neostigmine (Prostigmin Bromide) and edrophonium (Enlon, Tensilon) have shown benefits in some reports of tetrodotoxin intoxication (for example, pufferfish toxin similar to the blue ring octopus toxin), but have not undergone clinical trials in blue-ringed octopus envenomations.
- 4-Aminopyridine is another drug reported to reverse tetrodotoxin effects in experimental animals; however, it has been used in patients with multiple sclerosis.
- There is no antivenin available for blue-ringed octopus bites.
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Reviewed on 7/21/2022
Auerbach, P., et al. Field Guide to Wilderness Medicine, 7th Ed. Elsevier, 2016.