Sarcocystis neurona subsp. shedding

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., 2016, Detection and characterization of diverse coccidian protozoa shed by California sea lions, International Journal for Parasitology: Parasites and Wildlife 5 (1), pp. 5-16 : 13

3.5. Evidence of S. neurona shedding by free-ranging sea lions

In light of the unexpected findings revealed during cell culture analysis of fecal samples from stranded hospitalized sea lions, we screened all DNA extracted from frozen, pelleted oocysts of both hospitalized and field-collected fecal samples using S. neurona / S. falcatula -specific ITS 1500 primers. While none of the additional frozen, pelleted oocyst samples collected from hospitalized animals were PCR-positive for S. neurona -like DNA (including those remaining for CSL10089, CSL10092 and CSL10100), two fecal samples collected at Point Lobos ( Fig. 3 , samples PL11 and PL27) produced ~500 bp products in the ITS 1500 PCR reaction ( Table 3 ). Additional primers (Sn-ITS) targeting the ITS-1 region of S. neurona produced amplicons with sequences identical to hospitalized sea lion zoites collected in the present study as well as S. neurona isolated in other animals (See Supplementary data). All other attempts to amplify S. neurona in samples PL11 and PL27 using alternative primers failed with the exception of microsatellite Sn7 which, in sample PL27, produced a sequence containing the di-nucleotide repeat CA 17 found in S. neurona and zoites isolated in CSL10089, CSL10092 and CSL10100 ( Table 4 ).

Figures

Fig. 3. Three California sea lion haul-out sites (red circles) on the central California coast where fecal samples were collected from free-ranging animals. Field sample identifiers for test-positive samples are given (Ãno-, PL- and WR-) at each location. Coccidian parasite genotypes and species amplified in sample DNA are indicated in parentheses: A, Coccidia A; B, Coccidia B; Sn, Sarcocystis neurona-like; unchar, uncharacterized species. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.).