Abstract
Sarcocystis neurona is an apicomplexan protozoan parasite that can infect sea otters (Enhydra lutris) and can potentially prove fatal.1-3 Sea otters act as intermediate hosts that support tissue cyst development that can cause pathologic disease within the skeletal muscle, myocardium and central nervous system.2-5 This case report discusses a male sea otter stranded in 1999 that came to the Oregon Coast Aquarium at 10d old. The patient presented October 2009 with an extremely distended urinary bladder; however, no physical evidence of mechanical urinary blockage was attained, nor were there neurologic clinical signs. The bladder was drained and the patient treated with antibiotics and analgesics. The patient presented 14d later with the same ailment and an indwelling urinary catheter was placed. Further diagnostics performed included a CT and MRI but proved inconclusive. S. neurona titers were drawn and yielded 1:2560 and the patient was started on antiprotozoal medication. The bladder remained flaccid and the patient was unable to urinate even after titers achieved sub 1:320 titers, considered below active infection6 and thus necessitated an indwelling catheter for 440d. Urinary catheter complications included at 60d the catheter was shortened to allow for better diving, at 270d mucus plug blockage necessitating catheter change and two separate UTIs occurred over 440d. After the patient proved unable to urinate and cystoscopy defined significant urethral damage, surgical modification was decided upon and bladder marsupialization was performed Jan 2011. To the authors' knowledge this is the first case of semi-permanent urinary catheterization and bladder marsupialization in a marine mammal.
Acknowledgements
The authors with to thank Jim Burke, Director of Husbandry and Life Support Systems, Judy Tuttle, Curator of Mammals and all the marine mammal trainers at the Oregon Coast Aquarium. The authors wish to thank all the staff at Animal Medical Care, Newport Oregon as well as Drs. Seguin and Diggs from the College of Veterinary Medicine, Oregon State University for their support. Finally, the authors wish to thank Dr. Melissa Miller for her further insight on the parasite and sea otters.
References
1. Miller MA, Conrad PA, Harris M, Hatfield B, Langlois G, Jessup DA, Magargla SL, Packham AE, Toy-Choutka S, Melli AC, Murray MA, Gulland FM, Grigg ME. A protozoal-associated epizootic impacting marine wildlife: mass-mortality of southern sea otters (Enhydra lutris nereis) due to Sarcocystis neurona infection. Vet Parasitol 2010; 172: 183–194.
2. Miller MA, Barr BC, Nordhausen R, James ER, Magargal SL, Murray M, Conrad PA, Toy-Choutka S, Jessup DA, Grigg ME. Ultrastructural and molecular confirmation of the development of Sarcocystis neurona tissue cysts in the central nervous system of southern sea otters (Enhydra lutris nereis). Int J Parasitol 2009; 39: 1363–1372.
3. Dubey JR, Rosypal AC, Rosenthal BM, Thomas NJ, Lindsay DS, Stanek JF, Reed SM, Saville WJ. Sarcocystis neurona infections in sea otter (Enhydra lutris): evidence for natural infections with sarcocysts and transmission of infection to opossums (Didelphis virginiana). J Parasitol 2001; 87: 1387–1393.
4. Rosonke BJ, Brown SR, Tornquist SJ, Snyder SP, Garner MM, Blythe LL. Encephalomyelitis associated with a Sarcocystis neurona-like organism in a sea otter. J Am Vet Med Assoc 1999; 215: 1839–1842.
5. Thomas NJ, Dubey JP, Lindsay DS, Cole RA, Meteyer CU. Protozoal meningoencephalitis in sea otters (Enhydra lutris): a histopathological and immunohistochemical study of naturally occurring cases. J Comp Pathol 2007; 137: 102–121.
6. Miller MA. Personal Communication In: Lewer D, ed, 2010.