a small man-of-war; it is often likened to a bee sting. The variation in skin reaction is related to the specific
toxicity of the venom, so that while Actinia species produce painful urticarial lesions, Anemonia species
induce paresthesias, edema, and erythema. Most commonly the initial skin lesion is centrally pale with a halo
of erythema and petechial hemorrhage. This is soon followed by edema and diffuse ecchymosis. If the
envenomation is severe, intense local hemorrhage, vesiculation, necrosis, skin ulceration, and secondary
infection may occur, particularly after the stings of certain species (Sagartia, Actinia, Anemonia,
Actinodendron, and Triactis). In Floridian waters, the turtle grass anemone Viatrix globulifera, translucent-
white and less than one inch in diameter, is very hazardous, particularly for fishermen wading on grass flats.
The Hell's fire sea anemone (Actinodendron plumosum) is aptly named. Systemic reactions are less likely
after the sting of an anemone than after that of a man-of-war; reactions include fever, chills, somnolence,
malaise, weakness, nausea, vomiting, and syncope. Fulminant fatal hepatic failure three days after a sea
anemone sting of approximately 3 cm diameter upon the scapula and complicated by coma, severe
coagulopathy, and renal failure has been attributed to Condylactis (commonly found in reefs and lagoons of
south Florida, the Bahamas, and the Caribbean) on the basis of a positive serum test of IgG by ELISA at a
dilution of 1:450.
In most cases, mild envenomations resolve within 48 hours. More severe reactions, characterized by
discoloration and vesicle formation, may become indolent, with eschar leading to residual hyperpigmentation,
hypopigmentation, or keloid formation.
Sponge fisherman's (diver's) disease is caused by contact with an anemone (Sagartia or Actinia) that
attaches itself symbiotically to the base of a sponge. A few minutes after contact with the sponge, the victim's
skin begins to itch and burn, with development of erythema and small vesicles. As described previously, this
transforms to a darkened purple appearance, with frequent systemic components (headache, nausea, vomiting,
fever, chills, and muscle spasm).
Treatment. Treatment for an anemone envenomation is similar to that for the sting of Physalia species.
The dermatitis is frequently more severe and may require prolonged wound care consisting of debridement
and antibiotic therapy for secondary infection. The healing process is generally slower after an anemone sting
than after a man-of-war envenomation.
ECHINODERMATA
The phylum Echinodermata ("spiny skin") has five classes: sea lilies, brittle stars, starfish, sea urchins,
and sea cucumbers. Only the last three are of human medical interest, although some brittle stars carry toxins
capable of causing paralysis and death in small animals.
Starfish
Life and Habits. Starfish are simple, free-living, and stellate echinoderms covered with thorny spines
of calcium carbonate crystals held erect by muscle tissue. The creatures move upon the ocean floor by means
of tube feet located under the arms (rays). They eat other echinoderms, mollusks, coral, worms, and poisonous
shellfish. Starfish proliferation and destruction of coral beds within the Great Barrier Reef off the coast of
Australia is a conservation issue of international concern. The starfish everts its membranous stomach through
its mouth and secretes digestive enzymes that destroy coral polyps. Only the stark white coral skeleton
remains. The crown-of-thorns starfish (Acanthaster planci) is found in the coral reef communities of the Great
Barrier Reef, throughout the Pacific and Indian Oceans, in the Red Sea, and in the Gulf of California.
Venom and Venom Apparatus. Glandular tissue interspersed in or underneath the epidermis (integument)
produces a slimy venomous substance. The carnivorous Acanthaster planci is a particularly venomous species
normally 25 to 35 cm in diameter, which attains sizes of up to 70 cm in diameter, with 7 to 23 arms. The
sharp, rigid, and venomous aboral spines of this animal may grow to 4 to 6 cm. Potentially toxic saponins and
histamine-like compounds have been isolated from the spine surfaces; crude venom extracts demonstrate
hemolytic, capillary permeability increasing, myotoxic (phospholipase A
2
), myonecrotic, and anticoagulant
effects. A. planci lethal factor is a potent hepatotoxin in laboratory animals. "Plancinin" is an anticoagulant
purified from the crown-of-thorns starfish. This peptide shows activity in mice which suggests a longer
duration of action than heparin. Severe systemic hypotension,, thrombocytopenia, and leukopenia were
induced by A. planci venom in dogs. Indomethacin, a cyclooxygenase inhibitor, suppressed the hypotension.
A. planci venom caused smooth (uterine) muscle contraction in rats, which was blocked by inhibitors of
prostaglandin synthesis, but not by atropine.
