Hazardous aquatic life and aquatic infections

Sharks

The jaws of the shark contain rows of razor-sharp teeth, which can bite down with extreme force. The result is a wound with loss of tissue that bleeds freely and can lead rapidly to shock (see page 70).

The basic management of a major bleeding wound is described on page 60. Even if a shark bite appears minor, the wound should be washed out and bandaged, and the victim taken to a doctor. Often, the wound will contain pieces of shark teeth, seaweed, or sand debris, which must be removed to avoid a nasty infection. Like other animal bites, shark bites should not be sewn or taped tightly shut, to allow drainage. This helps prevent serious infection. The victim should be started on an antibiotic to oppose Vibrio bacteria (trimethoprim–sulfamethoxazole, doxycycline, or ciprofloxacin). (See fluoroquinolone antibacterial drugs precaution on page 498.)

The skin of many sharks is rough, like sandpaper, and can cause a bad scrape. If this occurs, it should be managed similar to a second-degree burn (see page 128).

Shark avoidance

• 1.

  Seek the advice of locals before entering waters where shark attacks have occurred.

• 2.

  Don’t enter waters posted with shark warnings.

• 3.

  Obey lifeguards if they request you to leave the water. Do so slowly and quietly.

• 4.

  Avoid shark-infested waters, particularly at dusk and after dark. Don’t dive in known shark feeding grounds. Avoid pinniped (e.g., sea lions and seals) rookeries and congregation areas.

• 5.

  Swim in groups. Sharks tend to attack single swimmers. Don’t splash on the surface or create a commotion in the water.

• 6.

  When diving or swimming, avoid deep drop-offs, sandbars, jetties, areas where birds are diving into the water, where there are leaping baitfish, murky water (e.g., recent storm), river mouths, or areas near sewage outlets. Don’t stray far from shore.

• 7.

  Don’t swim in waters frequented by recreational or commercial fishers.

• 8.

  Don’t swim with dogs or horses in the water.

• 9.

  Pods of dolphins or porpoises might indicate the presence of sharks. If they head inshore, exit the water.

• 10.

  Don’t tether captured (speared, for example) fish to your body.

• 11.

  Don’t corner or provoke sharks. Don’t touch or harass any shark.

• 12.

  If a shark appears, leave the water with slow, purposeful movements. Don’t panic or splash. If a shark approaches while you’re diving in deep water, attempt to position yourself so that you are protected from the rear. If a shark moves in, attempt to strike a firm blow to the snout.

• 13.

  If you’re stranded at sea and a rescue helicopter arrives to extract you from the water, exit the water at the earliest opportunity.

Barracudas

Barracudas might bite victims and create nasty wounds with their long canine-like teeth. These wounds are managed similar to shark bites (see earlier). Because barracudas seem to be attracted to shiny objects, the swimmer, boater, or diver is advised to not wear bright metallic objects, particularly not a barrette in the hair or anklet dangled on a leg near the surface from a boat or dock.

Moray eels

Although they look quite ferocious, moray eels seldom attack humans, unless provoked. They have muscular jaws equipped with sharp fanglike teeth, which can inflict a nasty bite. The usual wound is one or more punctures but can be a large and deep cut. A moray tends to bite and hold on.

A moray bite should be managed similar to a shark bite (see page 394). Even if the bite is very small, it should be examined by a physician to be sure that all tooth fragments have been removed. If the bite is more than superficial and, on the hand, on the foot, or near a joint, the victim should be started on an antibiotic (trimethoprim–sulfamethoxazole, doxycycline or ciprofloxacin) to oppose Vibrio bacteria. Avoid sewing, or otherwise tightly closing a moray bite unless absolutely necessary. (See fluoroquinolone antibacterial drugs precaution on page 498.)

Sponges

Natural sea sponges can be toxic “fresh” or dried. They can cause two types of skin reaction. The first is an allergic type similar to that caused by poison oak (see page 257), with the difference that the reaction generally occurs within an hour after the sponge is handled. The skin becomes red, with burning, itching, and occasional mottling or blistering. The second type of reaction is caused by small spicules of silica from the sponges that are broken off and embedded in the outermost layers of the skin. This causes irritation, redness, and swelling. When large skin areas are involved, the victim might complain of fever, chills, fatigue, dizziness, nausea, and muscle cramps. Untreated, minor sponge-induced rashes resolve in 3 to 7 days; more severe reactions might cause the skin to peel after a week to 10 days.

Because it’s difficult to tell precisely which type of skin reaction has occurred, if a person develops a rash after handling a sponge, undertake the following therapy:

• 1.

  First, gently dry the skin. Then, apply the sticky side of adhesive tape to the skin and peel it off. This will remove most sponge spicules that are present. An alternative is to apply a thin layer of rubber cement or a commercial facial peel, let it dry and adhere to the skin, and then peel it off.

• 2.

  Soak the affected skin with white vinegar (5% acetic acid) for 15 minutes three times a day. This can be done by wetting a gauze pad or cloth with vinegar and laying it on the skin. If vinegar is not available, use isopropyl (rubbing) alcohol 40%.

• 3.

  Again dry the skin, and then apply hydrocortisone lotion (0.5% to 1%) thinly twice a day until the irritation is gone. Don’t use topical steroids before decontaminating with vinegar; this might worsen the reaction.

If the rash worsens (blistering, increasing redness or pain, swollen lymph glands), this might indicate an infection, and the victim should be started on an antibiotic to oppose Vibrio bacteria (trimethoprim–sulfamethoxazole, doxycycline, or ciprofloxacin). (See fluoroquinolone antibacterial drugs precaution on page 498.) If the rash is persistent but there is no sign of infection, a 7-day course of oral prednisone in a tapering dose (for a 150-lb, or 68-kg, person, begin with 70 mg and decrease by 10 mg/day) might be helpful. Corticosteroids should always be taken with the understanding that a rare side effect is serious deterioration of the head (“ball” of the ball-and-socket joint) of the femur, the long bone of the thigh. Corticosteroids are interchangeable to a certain degree. If you must substitute, here is a rough measure of equivalence: 20 mg prednisone equals 16 mg methylprednisolone equals 3 mg dexamethasone.

Jellyfish

Jellyfish is the term commonly used to describe an enormous number of marine animals that are capable of inflicting a painful, and occasionally life-threatening, sting. These include fire coral, hydroids, jellyfish (including sea wasps), and anemones. The stings occur when the victim comes into contact with the creature’s tentacles or other appendages, which can carry millions of microscopic stinging cells (cnidocytes), each cell equipped with a toxin-laden microscopic stinging apparatus (nematocyst). Depending on the species, size, geographic location, time of year, and other natural factors, stings can range in severity from mild burning and skin redness to excruciating pain and severe blistering with generalized illness (nausea, vomiting, shortness of breath, muscle spasms, low blood pressure, and so on). Broken-off tentacles that are fragmented in the surf or washed up on the beach can retain their toxicity for months and should not be handled, even if they appear to be dried out and withered.

The dreaded box jellyfish (Chironex fleckeri) of northern Australia and the Indo-Pacific contains one of the most potent animal venoms known. A sting from one of these (or related) creatures can induce death in minutes from cessation of breathing, abnormal heart rhythms, and profound low blood pressure (shock). A sting from the Irukandji (Carukia barnesi) causes a syndrome of muscle spasm (back pain), sweating, nausea and vomiting, high blood pressure, and perhaps death. Priapism occurs rarely.

Be prepared to treat an allergic reaction following a jellyfish sting (see page 78).

The following therapy is recommended for all unidentified jellyfish and other creatures with stinging cells, including the box jellyfish, Portuguese man-of-war (“bluebottle”), Irukandji, fire coral, stinging hydroid, sea nettle, and sea anemone:

• 1.

  Don’t rub the wound.

• 2.

  If the sting is thought to be from the box jellyfish (C. fleckeri), immediately flood the wound with vinegar (5% acetic acid). A sting from the Australian Physalia physalis , a recently differentiated species, should not be doused with vinegar.

• 3.

  Treat a severe allergic reaction if such is present (see page 78).

• 4.

  Keep the victim as still as possible. Continually apply the vinegar until the victim can be brought to medical attention. If you are out at sea or on an isolated beach, allow the vinegar to soak the tentacles or stung skin for 10 minutes before you attempt to remove adherent tentacles or further treat the wound. In Australia, surf lifesavers (lifeguards) might carry antivenom, which is given as an intramuscular injection at the first aid scene. The pressure immobilization technique is no longer recommended as a therapy for jellyfish stings.

• 5.

  For all other stings, if a topical decontaminant (vinegar or isopropyl [rubbing] alcohol) is available, pour it liberally over the skin or apply a soaked compress. Some authorities advise against the use of alcohol on the theoretical grounds that it has not been proved beyond a doubt to help. However, some clinical observations support its use. Since not all jellyfish are identical, it’s extremely helpful to know ahead of time what works for the stingers in your specific geographic location. Vinegar might not work as well to treat sea bather’s eruption (see page 258); a better agent might be a solution of papain (such as unseasoned meat tenderizer—see below for precaution about duration of therapy). For a fire coral sting, citrus (e.g., fresh lime) juice that contains citric, malic, or tartaric acid might be effective. Topical lidocaine 4% might effectively numb any jellyfish sting, and also perhaps lessen the envenomation.

• 6.

  Until the decontaminant is available, you can rinse the skin with seawater. Don’t rinse the skin gently with fresh water or apply ice directly to the skin, as these might worsen the envenomation. A brisk freshwater stream (forceful shower) might have sufficient force to physically remove the microscopic stinging cells, but nonforceful application is more likely to cause the cells to fire, increasing the envenomation. A nonmoist ice or cold pack may be useful to diminish pain, but take care to wipe away any surface moisture (condensation) before the application. Observations from Australia suggest that hot (nonscalding to tolerance) water (113°F [45°C]) application or immersion might diminish the sting of the Portuguese man-of-war from that part of the world. The generalization of this observation to treatment of other jellyfishes, particularly in North America, should not automatically be assumed because application of fresh water worsens certain envenomations.

• 7.

  Apply soaks of vinegar or lidocaine for 30 minutes or until pain is relieved. Baking soda powder or paste is recommended to detoxify the sting of certain sea nettles, such as the Chesapeake Bay sea nettle. A paste made from unseasoned meat tenderizer (don’t exceed 15 minutes of application time, particularly not on the sensitive skin of small children) or papaya fruit might be helpful. These contain papain, which might also be quite useful to alleviate the sting from the thimble jellyfish that causes sea bather’s eruption (see page 258). Don’t apply any organic solvent, such as kerosene, turpentine, or gasoline. Perfume, aftershave, or high-proof liquor may worsen the skin reaction. While likely not harmful, urinating on a jellyfish, or any other marine, sting has never been proved to be effective.

• 8.

  After decontamination, apply a lather of shaving cream or soap and shave the affected area with a razor. In a pinch, you can use a paste of sand or mud in seawater and a clamshell. If a topical decontaminant (see numbers 1 and 2) is not available, simply applying a lather of shaving cream and shaving the affected area might lessen the pain from a sting.

• 9.

  Reapply the lidocaine, vinegar, or rubbing alcohol soak for 15 minutes.

• 10.

  Apply a thin coating of hydrocortisone lotion (0.5% to 1%) twice a day. Anesthetic ointment (such as lidocaine hydrochloride 2.5% or a benzocaine-containing spray) might provide short-term pain relief.

• 11.

  If the victim has a large area involved (an entire arm or leg, face, or genitals), is very young or very old, or shows signs of generalized illness (nausea, vomiting, weakness, shortness of breath, chest pain, and the like), seek help from a doctor. If a child has placed tentacle fragments in their mouth, have them swish and spit whatever potable liquid is available. If there is already swelling in the mouth (muffled voice, difficulty swallowing, enlarged tongue and lips), don’t give anything by mouth, protect the airway (see page 18), and rapidly transport the victim to a hospital.

Be aware that a jellyfish sting can cause a persistent or recurring rash for a year or more. If this happens, seek the care of a dermatologist, who can prescribe drugs that modify this type of allergic reaction.

To prevent jellyfish stings, an ocean bather or diver should wear, at a minimum, a synthetic nylon-rubber (Lycra [DuPont]) dive skin. Safe Sea Sunblock with Jellyfish Sting Protective Lotion ( www.getsafesea.com ), which is both a sunscreen and a jellyfish sting inhibitor, has been shown to be effective in preventing stings from many jellyfish species. Give all jellyfish a wide berth when swimming or diving.

Other prevention measures include being aware of surface jellyfish, not diving into water headfirst, checking snorkel and scuba mouthpieces carefully for tentacle fragments, watching out for stinging tentacles on ropes—anchor lines—fishing lines, and obeying posted warnings. If “stinger enclosures” are present, don’t venture beyond them.

Coral and barnacle cuts

Cuts and scrapes from sharp-edged coral and barnacles tend to fester and become infected wounds. Treatment for these cuts is as follows:

• 1.

  Scrub the cut vigorously with soap and water, and then flush the wound with large amounts of water.

• 2.

  Flush the wound with a half-strength solution of hydrogen peroxide in water. Rinse again with water.

• 3.

  Apply a thin layer of bacitracin or mupirocin ointment, or mupirocin cream, and cover with a dry, sterile, nonadherent dressing. If no ointment or dressing is available, the wound can be left open. Thereafter, it should be cleaned and redressed twice a day.

• 4.

  If the wound develops a poorly healing pus-laden crust, you can use wet-to-dry dressing changes to remove the upper nonhealing layer to expose healthy, healing tissue. This is done by putting a dry, sterile gauze pad over the wound (without any underlying ointment), soaking the gauze pad with saline or a dilute antiseptic solution (such as 1% to 5% povidone–iodine in disinfected water), allowing the liquid to dry, and then “brutally” ripping the bandage off the wound. The dead and dying tissue adheres to the gauze and is lifted free. The pink (hopefully), slightly bleeding tissue underneath should be healthy and healing. Dressings are changed once or twice a day. Use wet-to-dry dressings for a few days, or until they become nonadherent. At that point, switch back to the treatment in the previous paragraph.

  • If the wound shows signs of infection (extreme redness, pus, swollen lymph glands) within 24 to 48 hours after the injury, start the victim on an antibiotic to oppose Vibrio bacteria (e.g., trimethoprim–sulfamethoxazole, doxycycline or ciprofloxacin), as well as an antibiotic to oppose Staphylococcus bacteria (e.g., dicloxacillin or cephalexin). (See fluoroquinolone antibacterial drugs precaution on page 498.)

• 5.

  Coral poisoning occurs if coral cuts are extensive, or the cuts are from a particularly toxic species. The symptoms include a coral cut that heals poorly or continues to drain pus or cloudy fluid, swelling around the cut, swollen lymph glands, fever, chills, and fatigue. An antibiotic (see step 4) should be started, and the victim seen by a physician, who may elect to treat the victim for a week or two with an oral corticosteroid.

Sea urchins

Some sea urchins are covered with sharp venom-filled spines ( Fig. 246 ) that can easily penetrate and break off into the skin, or with small pincer-like appendages ( Fig. 247 ) that grasp the victim and inoculate them with venom from a sac within the pincer. Sea urchin punctures or stings are painful wounds, most often of the hands or feet. If a person receives many wounds simultaneously, the reaction might be so severe as to cause difficulty in breathing, weakness, and collapse. The treatment for sea urchin wounds is as follows:

• 1.

  Immerse the wound in nonscalding hot water to tolerance (110°F to 113°F, or 43.3°C to 45°C). This frequently provides sufficient pain relief. Administer appropriate pain medicine.

• 2.

  Carefully remove any readily visible spines. Don’t dig around in the skin to fish them out as it risks crushing the spines and making them more difficult to remove. Don’t intentionally crush the spines. Purple or black markings in the skin immediately after a sea urchin encounter don’t necessarily indicate the presence of a retained spine fragment. Such discoloration is often dye leached from the surface of a spine, commonly from a black urchin ( Diadema species). The dye will be absorbed over 24 to 48 hours, and the discoloration will disappear. If there are still black markings after 48 to 72 hours, a spine fragment is likely present.

• 3.

  If the sting is caused by a species with pincer organs, use hot-water immersion and then apply shaving cream or a soap paste and shave the area.

• 4.

  Seek the care of a physician if you feel that spines have been retained in the hand or foot, or near a joint. They might need to be removed surgically, in order to minimize infection, inflammation, and damage to nerves or important blood vessels.

• 5.

  If the wound shows signs of infection (extreme redness, pus, swollen lymph glands) within 24 to 48 hours after the injury, or if the spine is felt to have penetrated a joint, start the victim on an antibiotic to oppose Vibrio bacteria (e.g., trimethoprim–sulfamethoxazole, doxycycline or ciprofloxacin), as well as an antibiotic to oppose Staphylococcus bacteria (e.g., dicloxacillin or cephalexin). (See fluoroquinolone antibacterial drugs precaution on page 498.)

• 6.

  If a spine puncture in the palm of the hand results in a persistent swollen finger without any sign of infection (fever, redness, swollen lymph glands in the elbow or armpit), it might become necessary to treat a 150-lb (68-kg) victim with a 7-day course of oral prednisone in a tapering dose (begin with 70 mg and decrease by 10 mg per day). Corticosteroids should always be taken with the understanding that a rare side effect is serious deterioration of the head (“ball” of the ball-and-socket joint) of the femur, the long bone of the thigh.