The etiologic agent of seal finger (speck finger) is unknown. Seal fin
ger occurs after a seal bite, and the symptoms include acute pain, swe
lling, discharge, and, in some cases, there is joint involvement. The
discovery of Mycoplasma species in epidemics of seal disease prompted
attempts to link seal finger to mycoplasma. Mycoplasma species were is
olated in cultures of a specimen from the finger of an aquarium traine
r who was bitten by a seal and of a specimen from the front teeth of t
he biting seal. The two Mycoplasma isolates were identical biochemical
ly; they were serum-dependent and hydrolyzed arginine. The isolates we
re susceptible to tetracycline but resistant to erythromycin. By growt
h inhibition and immunofluorescent antibody tests, both strains were i
dentified as Mycoplasma phocacerebrale, a mycoplasma isolated in an ep
idemic of seal disease occurring in the Baltic Sea. The patient's infe
ction was treated successfully with tetracycline. To our knowledge, th
is is the first case in which a mycoplasma has been associated with se
al finger.