Abstract
A weanling female northern elephant seal (Mirounga angustirostris) was admitted to the Marine Mammal Care Center Fort MacArthur, San Pedro CA 2007 for rehabilitation after stranding in Long Beach, CA in May 2007. This 130 cm 38.7 kg weanling had bilateral cataracts and was not releasable. She was accepted for permanent captive placement at Adventure Aquarium Camden, NJ. Prior to placement, serology revealed a positive antibody titer to Toxoplasma gondii, a normal serum chemistry and complete blood count. The animal, clinically healthy other than a sparse hair coat and multifocal ulcerative dermatitis, subsequently died of disseminated toxoplasmosis and toxoplasmal meningoencephalitis. T. gondii has previously been documented in elephant seals,1,2 but seroprevalence in this species has not been reported. This case prompted a serosurvey to evaluate the prevalence of antibodies to T. gondii in stranded northern elephant seals. Sera were collected from stranded elephant seals in Los Angeles County between August 2008 and October 2009 on admittance and throughout the rehabilitation period. A total of 165 samples from 93 animals were tested by IFAT at UC Davis (Conrad Laboratory), a test previously validated in sea otters (Enhydra lutris).3 As this assay has not been validated in the northern elephant seal, titers were considered positive if dilutions were greater than 1:1,280. A seroprevalence of 7.5% (7/93) was found and is similar to the seroprevalence found in harbor seals in Puget Sound, WA.4 Positive antibody titers ranged from 1:5,120 to 1:40,960. Preliminary nested PCR-RFLP genotyping performed on a subset of tissues from 4 animals identified T. gondii in two animals consistent with types II or III, while a third animal exhibited an atypical genotype. Mortality in seropositive animals was 85% (6/7), but histopathology did not attribute death to T. gondii infection. Results indicate that elephant seals are susceptible to infection with T. gondii and despite a low mortality rate associated with infection it should be considered as a differential in animals with elevated titers.
Acknowledgements
This project was funded by a competitive grant from the Oiled Wildlife Care Network. Financial support for the Marine Mammal Care Center Fort MacArthur was also received from Houghton Mifflin Harcourt Publishing and John H. Prescott Grant # NA07NMF439022. This project could not have been completed without the support of Michael Ziccardi, Lavonne Hull, Suzana Tkalcic, David Bard, Michael Remski, Pat Bernard, Phyllis Summers, the volunteers of the Marine Mammal Care Center Fort MacArthur, and the rescue organizations that serve Los Angeles County including the California Wildlife Center, Marine Animal Rescue and Long Beach Animal Control.
References
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