Abstract
A female adult California sea lion (Zalophus californianus) stranded with seizure behavior. The animal entered a stranded animal rehabilitation program and was treated with supportive care and phenobarbital to reduce seizure activity. On day 3 in rehabilitation, the animal aborted a fresh late-term fetus. The placenta and fetus were grossly within normal limits. On histologic review, the fetus demonstrated no significant lesions. The placenta demonstrated multifocal areas of acute necrosis with neutrophilic infiltrates. Scattered trophoblasts demonstrated a foamy basophilic cytoplasm with marginated nuclei. Modified acid-fast stains (Fite's) demonstrated acid-fast positive cocco-bacilli organisms measuring 0.5-1 µm within these cells. Electron microscopy demonstrated intracellular pleomorphic round to elongate organisms within phagolysosomes. This morphology is consistent with published reports of Coxiella burnetii in ruminants.1 Immunohistochemistry using polyclonal antibodies demonstrated positive staining of these organisms. Polymerase chain reaction and bacterial 16S rRNA gene sequence obtained from placenta tissue confirmed the organism as Coxiella sp.
Abortion in sea lions is known to occur related to domoic acid intoxication.2 However, Coxiella sp. organisms can also cause fresh, late-term abortions and should be added to the list of potential etiologies in sea lion abortion. The differentiating factors are necrotizing placentitis and identification of intracellular organisms. Further investigations related to this agent should focus on the role of Coxiella sp. in abortion storms in pinnipeds and serologic screening for prevalence in wild pinniped populations.
References
1. Moore JD, Barr BC, Daft BM, O'Connor MT 1991. Pathology and diagnosis of Coxiella burnetii infection in a goat herd. Vet Pathol 28:81-84.
2. Brodie EC, Gulland FMD, Greig DJ, Hunter M, Jaakola J, St. Leger J, Leighfield TA, Van Dolah FM 2006. Domoic acid causes reproductive failure in California sea lions (Zalophus californianus). Marine Mammal Science 22:700-707.