Detection and characterization of diverse coccidian protozoa shed by California sea lions. Issue 1 (April 2016)

• Record Type: Journal Article
• Authors: Girard, Yvette A.; Johnson, Christine K.; Fritz, Heather M.; Shapiro, Karen; Packham, Andrea E.; Melli, Ann C.; Carlson-Bremer, Daphne; Gulland, Frances M.; Rejmanek, Daniel; Conrad, Patricia A.
• Is Part Of: International journal for parasitology. Volume 5:Issue 1(2016)
• Page Start: 5
• Page End: 16
• Publication Date: 2016-04
• Subjects: Tissue cyst-forming coccidia -- Sarcocystidae -- Neospora sp. -- Sarcocystis neurona -- California sea lions -- Marine mammals; Parasites -- Periodicals; Parasitology -- Periodicals; Animals -- Periodicals; Wildlife diseases -- Periodicals; Parasites -- Periodicals; Animals, Wild -- Periodicals; Animals; Parasites; Parasitology; Wildlife diseases; Periodicals; 591.7857
• DOI: 10.1016/j.ijppaw.2015.11.003
• Languages: English
• ISSNs: 2213-2244

Abstract

Abstract: Tissue-cyst forming coccidia in the family Sarcocystidae are etiologic agents of protozoal encephalitis in marine mammals including the federally listed Southern sea otter ( Enhydra lutris ). California sea lions ( Zalophus californianus ), whose coastal habitat overlaps with sea otters, are definitive hosts for coccidian protozoa provisionally named Coccidia A, B and C. While Coccidia A and B have unknown clinical effects on aquatic wildlife hosts, Coccidia C is associated with severe protozoal disease in harbor seals ( Phoca vitulina ). In this study, we conducted surveillance for protozoal infection and fecal shedding in hospitalized and free-ranging California sea lions on the Pacific Coast and examined oocyst morphology and phenotypic characteristics of isolates via mouse bioassay and cell culture. Coccidia A and B were shed in similar frequency, particularly by yearlings. Oocysts shed by one free-ranging sea lion sampled at Año Nuevo State Park in California were previously unidentified in sea lions and were most similar to coccidia infecting Guadalupe fur seals ( Arctocephalus townsendi ) diagnosed with protozoal disease in Oregon (USA). Sporulated Coccidia A and B oocysts did not replicate in three strains of mice or in African green monkey kidney cells. However, cultivation experiments revealed that the inoculum of fecally-derived Coccidia A and B oocysts additionally contained organisms with genetic and antigenic similarity to Sarcocystis neurona ; despite the absence of detectable free sporocysts in fecal samples by microscopic examination. In addition to the further characterization of Coccidia A and B in free-ranging and hospitalized sea lions, these results provide evidence of a new role for sea lions as putative mechanical vectors of S. neurona, or S. neurona -like species. Future work is needed to clarify the distribution, taxonomical status, and pathogenesis of these parasites in sea lions and other marine mammals that share their the near-shore marine environment. Graphical abstract: Highlights: Diverse coccidian protozoa shed by California sea lions (CSL) were characterized. Oocyst shedding patterns, taxonomy, morphology and pathogenicity were examined. Mice and cell cultures were not susceptible to Coccidia A or B of CSL origin. Sarcocystis neurona -like zoites grew in cells inoculated with CSL fecal samples. California sea lions may serve as mechanical vectors of an S. neurona -like organism.