Poster
Although pygmy sperm whales (Kogia breviceps) are amongst the most commonly stranded
cetacean species along the eastern coast of the United States, they are infrequently found stranded along the west
coast. Between 1983 and 1997, only 13 animals were recorded stranded along the California coast. These animals were
found from San Diego in the south to Humboldt County in the north (Table 1). Seven of the animals were adults, two
were subadults, two were calves and, in two cases, age was unknown. Weights ranged from 79 to 386 kg, lengths from
115 cm to 303 cm. Detailed histopathologic examination was only performed in 3 cases.
One animal (No. 7) that survived for 8 weeks in rehabilitation following stranding had gastric
ulcers and a necrotizing hemorrhagic pneumonia involving the right lung, from which Streptococcus bovis
variant 2, Pseudomonas putrefaciens, Aeromonas sobria and Clostridium sp. were isolated. A
second animal (No. 12) died within one hour of detection on the beach, with histologic changes suggestive of
cardiovascular collapse (renal cortical tubular ectasia with intraluminal cellular casts, marked diffuse hepatic
congestion, adrenocortical vascular congestion and hemorrhage).
The head was not available for examination, but sections of nematode parasites 30-40 cm long were
detected in subcutaneous tissues of the neck, and were associated with perilesional granulomatous and eosinophilic
inflammation. There was a neutrophilic and eosinophilic lymphadenitis with marked sinus edema, hemorrhage and
plasmacytosis in the cervical lymph node draining the subcutaneous tissue infected with the nematodes.
A third animal (No. 13) died within 2 hours of stranding with an acute multifocal interstitial
pneumonia. Multiple segments of nematodes 100-320 cm long were entwined with the subcutis and muscle fascia of the
head, neck and thorax. Sections of this nematode were morphologically compatible with Crassicauda magna,
previously observed in Kogia breviceps stranded in Australia. Viable worms were associated with marked
fibrosis, muscle atrophy and lysis but minimal inflammation, while necrotic sections of nematodes were associated
with granulomatous inflammation. One nematode extended through the intercostal muscles into the pleural cavity where
it was associated with a fibrinous pleuritis.
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