The stingrays make up one of the largest and most important group of venomous marine animals, and are the most commonly incriminated group of fishes involved in human envenomations. There are 7 species of stingrays found Atlantic coastal. It is estimated that the are more than 1500 stingray injuries per year in this country. Rays are nonaggressive scavengers and bottom feeders that burrow into the sand or mud to feed upon worms, mollusks, and crustaceans.
The venom organ of stingrays consists of one to four venomous stings on top of the tail. Each elongate, tapered spine is firmly attached by dense collagenous tissue and is edged on either side by a series of sharp teeth. Along either edge, on the underside of the spine, are the two glandular grooves, which house the soft venom glands. The entire spine is encased by the integumentary sheath, which also contains some glandular cells. The venom contains various toxins which can cause peripheral vasoconstriction, slowing of the heart, respiratory depression, seizures, balance disorders, coma, and even death.
Stingray “attacks” are purely defensive gestures. They occur when an unwary individual steps on a camouflaged creature while wading in shallow waters. The tail of the ray reflexly whips upward and, with amazing accuracy, thrusts the spine into the victim, producing a puncture wound or laceration. The integumentary sheath covering the spine is ruptured, and venom is released into the wound. Thus, a stingray wound is both a traumatic injury and an envenomation. Secondary bacterial infection is common. The lower extremities, particularly the ankle and foot, are involved most often, followed by the upper extremities, abdomen, and thorax. Fatalities have been reported secondary to intra-abdominal and thoracic trauma.
The envenomation itself classically demonstrates immediate (onset in less than 10 minutes) local intense pain, edema, and bleeding. The pain may radiate centrally and last for up to 48 hours. The wound is initially dusky or cyanotic and rapidly progresses to erythema and hemorrhagic discoloration. Systemic manifestations may include weakness, nausea, vomiting, diarrhea, sweating, vertigo, tachycardia, headache, syncope, muscle cramps, paralysis, hypotension, arrhythmias, and even death.
The success of therapy is largely related to the rapidity with which it is undertaken. Treatment is directed at combating the effects of the venom, alleviating pain, and preventing infection. The wound should be irrigated immediately with whatever cold fluid is at hand. If no sterile saline is available, sea water does nicely. This removes some venom, provides mild anesthesia, and induces local vasoconstriction, possibly retarding the absorption of the toxin. Local suction, if applied in the first 15—30 minutes, may be of some value, as may a loose tourniquet which occludes only superficial venous and lymphatic return. This should be released for 90 seconds every 10 minutes in order to preserve circulation.
As soon as possible, the wound should be explored and cleaned of any pieces of the sting’s integumentary sheath which continue to envenomate the victim. After the wound is thoroughly irrigated and cleansed, it should be soaked in hot water for 30—90 minutes. This relieves pain and attenuates the venom. There is no indication for the addition of ammonia, potassium permanganate, or formalin to the soaking solution. In these circumstances, they are tissue toxic and/or obscure visualization of the wound. Cold therapy is disastrous, and there are no data to support the use of antihistamines or steroids.
If there is no contraindication, pain control should be rapidly; narcotics may be necessary. Local infiltration of the wound 1—2% lidocaine (Xylocaine) without epinephrine may be very useful.
After the soaking procedure, the wound should be reexplored and, after sterile preparation, cleaned. Wounds should be closed loosely with drainage. Tetanus prophylaxis is standard. Prophylactic antibiotics are controversial but are frequently used because of the high incidence of secondary infection and sequent necrosis. All victims with significant envenomation should be observed for a period of hours for systemic side effects and supported appropriately.
The stingray spine can penetrate rubber boots and even the side of a wooden boat; therefore, a wet suit or pair of sneakers is not adequate protection. One must shuffle along through shallow waters known to frequented by stingrays and create enough turbulance to frighten off any nearby animals
My personal experience with these critters is that they are docile, even "friendly," to the point where they are easily handfed. There "skin" is soft, even velvet-like, and they seem to like to gently brush up against people who feed or even just swim with them. I have fed Lincoln Jones "pet" rays in Manjack Cove, and I know several people who have swam with them at Stingray City in the Caymans. It's quite the experience to have a six-foot stingray "hug" you with its wings. You simply don't want to step on one; something to remember when you're in the water shuffling around the sand.