Stings, Bites, and Poisoning from Dangerous Marine Animals

Jellyfish

Many of Mexico’s most beautiful beaches harbor the treacherous jellyfish. Twenty or more species are common in the waters around Mexico; most cause painful stings. Some are harmless, but a few rare species can be fatal. Jellyfish tentacles are armed with thousands of tiny needle-like filaments that can deliver small doses of venom just below the surface of a victim’s skin. Stings can be very painful, especially if an extensive area of the body is involved. Children, asthmatics, or people with a history of significant allergies may be badly affected, and some cases of respiratory distress and shock have been reported. Seek medical attention if there is shortness of breath, nausea, vomiting, severe dizziness, or a severe rash after a sting.

If you do find yourself among a school of jellyfish, try not to panic. Slowly tread water until you are sure you are clear of the school. If you are stung, rubbing your wounds may aggravate the pain. Do not immediately remove any stray tentacles from your body. If you are able, apply shaving cream, baking soda, or flour first and then after a few minutes scrape off the tentacle(s) with a knife or credit card after it has dried out a bit. This process prevents the further discharge of venom. Do not apply alcohol or vinegar despite what you may have heard. Vinegar may help prevent further venom discharge in some species, but can be harmful in others. Therefore, do not use vinegar unless one of the locals has seen what type of jellyfish has stung you and recommends that you use it.

Cold compresses or topical anesthetic sprays may be useful in relieving pain. Also, ammonia products such as Windex®, or certain over-the-counter salves, may help soothe the pain. Believe it or not, the primary component of urine is ammonia. If it is applied to a fresh sting, it may help ease your suffering. Meat tenderizer with papain, applied as a wet paste, destroys venom. Soaking the extremity in very warm (not scalding) water for up to 90 minutes may help deactivate the venom.

There is a new lotion on the market that prevents jellyfish stings and the stings of a number of other marine animals such as sea lice, sea nettle, coral, or sea anemone. The product, called SafeSea™, has the same protective chemical found in clown fish that prevents them from being stung. It is mixed with various strengths of SPF protection and it seems to work on most but not all subjects tested. It has not yet been tested on the Portuguese man-of-war jellyfish common to the waters surrounding Mexico, but it makes sense that it would work on all jellyfish.

Stingrays

Stingrays may be found just under the sandy surface of the ocean floor, typically in shallower waters. The stinger, used by the animal for protection from predators, is located at the end of the ray’s tail. Swimmers and divers are stung when they unknowingly step on the stingray and the long tail reflexively lashes out at the offending leg or ankle. Although the barb of a stingray is poisonous, most of the damage is caused by the actual wound itself or subsequent infection. If enough venom enters the blood stream, dizziness, nausea, vomiting, or fainting may occur.

If you or someone you know is stung by a stingray, treat it as you would any contaminated puncture wound. Immediately irrigate the wound with clean or sterile saline solution or water. The more you can irrigate the wound, the better your chance of avoiding a deep infection or abscess. Soak your arm or leg in warm, soapy water as often as you can. If you do develop any signs of wound infection, seek medical attention immediately.

If cleaning the wound has been delayed for more than three or four hours, you might consider preventive antibiotics. Appropriate antibiotics would include Augmentin or Biaxin. Stingray wounds are one reason why it is vital that your tetanus immunization is up-to-date.

Echinoderms: Starfish and Sea Urchin

Sea urchins are small, spiny, bottom dwellers, that if stepped on, can inject a venom that may cause nausea, vomiting, muscle cramps, shortness of breath, or localized swelling, redness, and numbness.

The spines are difficult to remove and may cause infection, especially if they have broken off and are lodged under the skin. If you are wounded by a sea urchin and your tetanus immunization is not up-to-date, remove easy-to-access spines and seek medical attention. Follow basic wound care treatment guidelines.

By soaking the affected limb in very warm, soapy water you may neutralize the toxins and clean out any wounds. If sea urchins are eaten and improperly prepared, they may cause significant intestinal disturbances.

Mexican starfish are not poisonous, but may cause cuts or abrasions if they are stepped on or mishandled. Follow routine wound care guidelines as applicable.

Poisonous Fish

Poisonous fish common to the waters surrounding Mexico include the scorpion (Scorpaena) and Zebra or Lion (Pterois) fish. These fish have long, venomous spines growing out of their skin. Stings from these fish are known to be extremely painful and cause severe swelling at the site of injury. The venom may be destroyed with heat, so soaking the extremity in very warm water (100°–115° F or about 50° C) for up to 90 minutes will help reduce the duration of pain. If the pain is severe, seek medical attention and request an anesthetic injection. Follow standard wound care precautions for puncture wounds.

Guidelines for Wound or Bite Care:

• Always thoroughly cleanse any bite or scratch with large quantities of soap and warm, running water. The more debris or bacteria that you can remove the better.
• Avoid topical antibiotic creams or gels. These preparations tend to inhibit drainage of bacteria from bite wounds and can often make them worse.
• Keep the wound clean by applying a sterile or very clean cloth dressing.
• Make sure your tetanus shot is up-to-date.
• Treat any bleeding with local pressure. On extremities, avoid constricting or tourniquet-like dressings whenever possible.
• Always try to capture and store any small insects or animals that bit you for later identification. If possible, quarantine larger animals for observation.