Cone Snail Sting

Molecular model of cone snail toxin that blocks skeletal muscle sodium channels, causing paralysis. Other toxins can block calcium channels and nicotinic acetylcholine channels in cardiac and nerve tissues.

What Is a Cone Snail?

A cone snail has a cone-shaped shell, head, and tentacles. There are approximately 500 species of cone snails.

Where Are Venomous Cone Snails found?

They live in the Indian and Pacific oceans, the Caribbean and Red seas, and along the coast of Florida. They are not aggressive.

The sting usually occurs when divers in deep reef waters handle the snails. Swimmers and snorkelers are unlikely to find cone snails in shallow intertidal waters. Their empty shells are prized items on sandy beaches. They are nocturnal (more active at night) and they tend to burrow themselves in the sand and coral during the day. Cone snail shells range in size from less than an inch to 9 inches long. Cone snails mainly hunt worms and other snails.

Are Cone Snails Dangerous?

A few varieties of cone snails eat fish, and these are the most harmful to humans.

To get its prey, the cone snail injects a rapid-acting venom from a dart-like tooth (radicula) or dagger. To do this, the head of the snail extends out of the shell. The toxin from cone snails in the Indo-Pacific region tends to be more harmful than other regions of the world.

What Do Cone Snails Look Like?

Cone snail shells.

Symptoms of cone snail sting include:

• Most stings occur on the hands and fingers due to handling.
• Mild stings are similar to a wasp or bee sting with localized burning and sharp stinging symptoms. They can be intense and also have numbness and tingling to the wounded area.
• Some sting symptoms can progress to include cyanosis (blueness at the site due to decreased blood flow), and even numbness or tingling involving an entire limb.
• Severe cases show total limb numbness that progresses to the area around the mouth (perioral) and then the entire body. Paralysis (inability to move a part or entire body) can occur leading to paralysis of the diaphragm which stops the ability to breathe.
• Coma and death can result in severe cases where the diaphragm is paralyzed.
• Other symptoms that can occur include
  • fainting (syncope),
  • itching,
  • loss of coordination,
  • heart failure,
  • difficulty speaking, 
  • difficulty breathing, and
  • double vision.
• Symptoms can begin within minutes or take days to appear after the venom is injected.

• If SCUBA diving, the diver stung should safely surface immediately accompanied by another diver.
• There is no antivenom available for cone snail stings.
• Use the pressure immobilization technique:
  • 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 joints.
  • The elastic bandage should be removed for 90 seconds every 10 minutes and then reapplied for the first 4 to 6 hours. (Hopefully medical care can be received within this time period.)
• Other treatment options that may help include:
  • Immerse the affected area in water as hot as is tolerable (water temperature not to exceed 140 F or 60 C).
  • Inject a local anesthetic into the wound area.
  • Some reports suggest that
  • Edrophonium (Enlon, Tensilon) 10 mg IV may be used as therapy for paralysis. A 2-mg test-dose should first be administered IV, and if effective, followed by an additional 8-mg dose IV. Atropine (Atreza, Sal-Tropine) 0.6 mg should be immediately available for intravenous administration in case of an adverse reaction to edrophonium.
  • A 2 to 4 mg dose naloxone (Narcan) given IV may help treat severe hypotension (low blood pressure).
  • Local excision (cutting out the area stung) by a health care professional (controversial and not widely recommended)
  • Incision and suction (controversial and not widely recommended)
• Avoid excessive movement and keep the patient calm and warm.
• CPR may be necessary. Artificial respiration may save the person's life.
• Do not cut into the wound, apply suction, or use a tourniquet.

• Avoid picking up cone shells; if a person does pick up a shell, they should be wearing proper gloves and carefully grasp the large end of the shell.
• If any part of the snail begins to stick out from the shell, the cone should be dropped immediately
• If you must carry the shell, carry it by the large end of the shell
• Never carry the shell inside a wet suit, clothing pocket, or dive suite buoyancy compensator.

• Seek medical treatment as soon as possible.
• Intensive care hospitalization, including use of a respirator, may be required.