Abstract
Coxiella burnetii infections in marine mammals are sparsely reported and primarily involve seroprevalence studies.1-3 In humans, acute and chronic infections are reported and can present with fever, epicarditis, pericarditis, embolic disease, osteomyelitis, and osteoarticular infections.4-6
A 12-year-old castrated male California sea lion (Zalophus californianus) under professional care presented with an acute onset of partial anorexia and lethargy that progressed to bilateral foreflipper immobility four days after presentation. The animal was only able to move by sliding on his abdomen. Blood work was initially unremarkable but progressed to a severe leukocytosis with a degenerative left shift, elevated D-dimers, and hyperglobulinemia. Despite treatment, the animal clinically declined and was euthanized due to anesthetic complications.
Gross necropsy lesions included bilateral subfascial abscesses at the epiphyses of the tibias; dark, friable bone marrow in the epiphyseal region of multiple bones; a pale epicardium covered in fibrin; and renal infarcts. Histopathology confirmed renal infarcts; chronic pericarditis with fibrosis, granulomatous myositis; and granulomatous periostitis, arthritis, and osteomyelitis with the presence of foamy macrophages and multinucleated giant cells. Acid-fast and Gram staining were negative for bacteria and PCR was negative for fungal organisms, Mycobacterium, Nocardia, Brucella species.
Seroconversion of Coxiella burnetii phase 2 titers (>1:2048) occurred one year prior to disease presentation with a positive phase 1 titer (1:256). Based on disease presentation, histopathology, and seroconversion the animal likely died due to complications of Coxiella burnetii infection. Coxiella burnetii should be a differential in marine mammals presenting with decreased mobility, cardiac lesions, embolic disease, and osteomyelitis.
Acknowledgements
The authors thank Drs. James Bailey and Ashley Hechler for their expert consultation in this case; the diagnostic imaging personnel at Naval Medical Center San Diego Balboa; the incredible training staff at the National Marine Mammal Foundation, Science Applications International Corporation, and U.S. Navy Marine Mammal Program; and the incredible veterinary technicians with the National Marine Mammal Foundation and U.S. Army Veterinary Corps for their hard work and dedication to the care of the animals.
*Presenting author
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