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The marine environment is increasingly important for recreation,
industry, and communications and is dangerous to humans for several
reasons: we can’t breathe in it, we can’t see
in it, and swimming must be learned. The marine environment is also
remote to points of definitive health care. Marine fauna can inflict
injury through trauma (often with infection) or envenomation. Many
marine animals have developed venomous systems of defense and predation.
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There is little information on the epidemiology of marine injuries
and envenomations. One U.S. study reviewed >6 years of aquatic animal
exposures reported to poison control centers. The most common exposures
were to jellyfish (31%), stingrays (16%), venomous
fish (including lionfish, catfish, and others) (28%), and
gastropods (6%).1 However, these percentages are likely to be biased toward more severe injuries and do
not include common minor injuries, such as envenomation by Physalia species,
seabather’s eruption, and sea urchin stings. In the U.S.,
thousands of cases of minor jellyfish stings occur yearly from Physalia species (Portuguese
man-of-war) and Chrysaora species. There is less
information on traumatic injuries except for details of shark attacks,
which are maintained in the International Shark Attack File. The file
reports almost 1000 attacks since 1990, with just over 10% being
fatal.2
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Sharks are from the subclass Elasmobranchii of the class Chondrichthyes (“cartilaginous
fishes”), which also includes skates and rays. Sharks are top-level
predators and are well equipped to inflict severe injuries. There are
about 400 species of shark, and human attacks have been described for
>30 species. Certain species, such as the white shark (Carcharodon carcharias),
the tiger shark (Galeocerdo cuvier), and several Carcharhinus species,
appear to be disposed to human attacks. Despite the public perception,
the risk of shark attack is extremely small compared with almost
any other injury. There are probably between 70 and 100 shark attacks
worldwide each year, with between 5 and 15 deaths.2,3 The mortality
of shark attacks has fallen from 40% in the 30 years following World
War II to current rates of approximately 10% to 20%.2 Death
is usually a result of lack of prehospital resuscitation, hemorrhagic
shock, or drowning.
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Three general types of unprovoked shark attack are described:
(1) hit-and-run attacks, in which the victim is seized and released,
or slashed on an extremity, before the victim has any time to react;
they often occur in shallow water and account for approximately
80% of shark attacks; (2) sneak attacks, or the “out-of-the-blue” attacks,
usually involving divers or swimmers in deeper water; and (3) bump-and-bite
attacks, in which the shark circles and bumps the victim prior to
attacking.3 These last two types tend to occur
in deeper water, are characterized by multiple and sustained attacks,
involve bigger sharks, and cause the majority of deaths by shark
attack.
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The direct traumatic effects of a shark attack depend upon the
severity ...