Sea Lion Bites

It seems that this is the week for aquatic animals to be irascible. A California sea lion has bitten at least 14 swimmers in the water of San Francisco's Aquatic Park Lagoon. While none of these bites has been serious, the prospect of being attacked and bitten has driven many enthusiasts from the water. According to reports, the animal appears to be watching victims from the shore. When the swimmers enter the water, the marine mammal follows and then makes its move to bump and bite them. The bites are nips, but carry an infection risk. Accordingly, the victims have been advised to take antibiotics. However, the San Francisco Department of Public Health has not recommended immunization against rabies.

The animal's behavior is not readily explained, as it does not appear to be defending a mate or any offspring. It is perhaps exhibiting territorial behavior, or as some have suggested, might be under the effects of toxic algae.

Sea lions and seals are usually mild-mannered mammals except during the mating season, when the males may become aggressive, and the breeding season, when both genders attack in defense of their newborn pups. Divers and swimmers should avoid ill-tempered and abnormally aggressive animals. There is nothing unique about the clinical aspects of these injuries, except for the post-bite infections.

“Seal finger” (also called "spekk finger" or "blubber finger") follows a bite wound from a seal or from contact of even a minor skin wound with a seal’s mouth or pelt. It has traditionally been an occupational hazard of seal hunters, but has now been noted in aquarium workers and persons trying to save seals. One case was attributed to a polar bear (which may or may not have eaten a seal) bite. The affliction is characterized by an incubation period of 1 to 15 (typically, 4) days, followed by painful swelling of the digit, with or without destructive joint involvement. As the lesion worsens, the skin becomes taut and shiny, while the entire hand may swell and take on a brownish violet hue. It is quite possible to have involvement of adjacent fingers. It is common for the affliction to run a protracted course.

Current thinking focuses upon Mycoplasma species as the inciting cause. Infection with Erysipelothrix rhusiopathiae is in the differential diagnosis, but usually is characterized by a more reddened and sharply-bordered rash spread amongst multiple fingers.

Tetracycline is the recommended therapy. Certain other antibiotics, such as ciprofloxacin, may be useful if tetracycline is not available. Preventive measures washing all wounds as soon as possible vigorously with soap and water.

Tags: sea lion, animal bite, wilderness medicine, outdoor medicine, healthline

photo by Paul Auerbach

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