What is Cone Snail Toxicity?
Scuba divers, both beginners and experts, are attracted to warm, tropical seas. However, diving in these areas requires extra care to avoid certain sea creatures that can pose a threat. One such creature is the Conus genus, a group of over 500 species of predatory snails. Though their primary targets aren’t humans, unsuspecting divers may pick up these cone-like snails as souvenirs, not realizing their danger. If a person gets stung by the snail, they could be injected with a venom strong enough to paralyze or even kill.
These snails, which are part of the Conidae family, live inside their spiral shells. They continue to grow and add to their patterned shells throughout their lives. While all the species look similar, some are more dangerous to humans than others. Cone snails can range in size from just a few centimeters to as long as 29 cm. They use a special appendage, called a siphon, to detect prey. The siphon is sensitive to their surroundings and helps them breathe. Some species even have eyestalks. Depending on the species, cone snails may feed on worms, other mollusks, or fish, with the ones feeding on fish being the most toxic to humans.
All cone snails can harm humans with their stings, but the geographic cone is the deadliest known species. Several human deaths have been traced back to this particular snail. People usually get stung while handling the snails, often on the palms and fingers.
Fish-eating snails use one of two primary hunting techniques: hook and line or net hunting. For the hook-and-line method, the snail uses a special appendage called a proboscis which houses a tooth or harpoon coated with venom. The second method uses a venomous harpoon that the snail releases in its wide-open mouth to catch fish. Once a harpoon has been used, the snail can’t re-use it. However, a cone snail has an average of twenty harpoons at different growth stages inside its body at a given time.
What Causes Cone Snail Toxicity?
The venom from cone snails is a complex mix of substances that can paralyze by interfering at different points in the body’s muscular system. Each species of cone snail has a unique combination of peptides, which are the elements that make up the venom. There’s a wide diversity in these venoms, with each snail estimated to have over 100,000 different active substances in its poison.
This venom’s complexity and the wide range of body processes it can affect have made it difficult to create an effective antidote for the poison.
Risk Factors and Frequency for Cone Snail Toxicity
Cone snails typically live in tropical waters like the Red Sea, the Caribbean, the Indian Ocean, and the Pacific. Yet, they can also be found in warmer depths off the coast of Florida. They prefer to stay in deep sea areas near reefs and are mostly active at night. During the day, they hide in the sand and generally only come into contact with humans if disturbed. Cone snail stings can be very dangerous, with reported mortality rates varying between 15% to 75%. However, it’s important to remember that deaths from cone snail stings can be prevented, so all deep-sea divers should be aware of this risk.
Signs and Symptoms of Cone Snail Toxicity
When stung by a cone snail, the first symptoms can vary based on both the snail species and the person who is stung. When stung by a cone snail that eats fish, the individual may experience anything from feeling a sharp pinprick to severe pain. There might also be local numbness, reduced blood flow, bluish skin, and tissue damage at the sting site, and in some instances, these effects can impact large areas of the body. As these snail venom affect nerve signals all over the body, other symptoms can develop. Initial symptoms include weakness, sweating, and vision changes, which can progress to overall muscle paralysis, breathing problems, cardiovascular collapse, and coma. If not treated, this can lead to death rapidly, typically within one to five hours. Less severe stings, those caused by cone snails that eat molluscs or worms, result in milder toxic effects. These can vary but may include numbness, a sensation of tingling, and inability to move limbs.
- Sharp pricking sensation to severe pain
- Local numbness
- Reduced blood flow
- Bluish skin
- Tissue damage
- Weakness
- Sweating
- Vision changes
- Overall muscle paralysis
- Breathing problems
- Cardiovascular collapse
- Coma
- Numbness (milder stings)
- Sensation of tingling (milder stings)
- Inability to move limbs (milder stings)
Testing for Cone Snail Toxicity
The selection of the right laboratory tests largely depends on the patient’s symptoms and any urgent health conditions that develop during their hospital stay. If the patient shows signs of widespread symptoms, initial diagnostic tests such as blood tests for body chemicals, a chest X-ray, and an EKG (a test that checks for problems with the heart’s electrical activity) might be the starting point during their hospitalization.
Treatment Options for Cone Snail Toxicity
If you are stung by a cone snail, the most crucial step is to rush to the hospital. The health team’s immediate focus will be on making sure you can breathe and that your heart is working properly. Breathing assistance using a machine might be needed, along with other supportive treatments at the hospital.
On the way to the hospital, there are a few things that can be done to slow down the spread of the venom. One method is called pressure immobilization. It involves tightly wrapping the affected body part, starting from the fingertips or toes and moving towards the center of the body. The wrap should be firm, but not too tight to cut off blood flow. Regular checks should be performed to ensure that the fingertips or toes remain pink in color. Removing the bandages for 90 seconds and then reapplying them every 10 minutes can be beneficial, but it should not delay you from getting to the hospital.
Some reports suggest that immersing the stung area in hot water (between 40 to 50 degrees Celsius) might help alleviate pain after getting stung by a cone snail. However, this is based mainly on personal experiences, and we need more scientific study before this can be recommended as a standard step.
What else can Cone Snail Toxicity be?
When someone has a medical incident in the ocean, it could be due to several factors:
- Allergy to something in the water
- A sting or bite from a jellyfish or other sea creature
- A bite from a sea snake
- A reaction to shellfish
Identifying the exact cause is vital in providing the appropriate care and treatment.
What to expect with Cone Snail Toxicity
Even when a patient gets the right treatment, there’s still a chance they might not survive. Getting the patient to a hospital quickly for breathing support and other forms of care is crucial for their chances of survival.