First molecular characterization of Sarcocystis miescheriana in wild boars (Sus scrofa) from Latvia

Various muscle samples of wild boar (Sus scrofa) from Latvia were studied for the presence of Sarcocystis infection by means of morphological and molecular methods. Sarcocysts were detected in 122 out of 140 (87.1%) wild boar examined. According to the morphological appearance of sarcocysts, the observed cysts belonged to one morphological type and resembled Sarcocystis miescheriana. Twenty-three sarcocysts isolated from the muscles of Latvian wild boars were molecularly characterized at 18S rRNA, ITS1 and cox1. Additionally, eight sarcocysts obtained from Lithuanian wild boars were subjected to molecular analysis in order to compare intraspecific genetic variability. The amplified 18S rRNA region using newly designed primers is sufficiently variable to separate S. miecheriana from S. suihominis. All Latvian and Lithuanian isolates were confirmed belonging to S. miescheriana. No genetic variation was detected within 18S rRNA and ITS1. By contrast, the high intraspecific genetic variability of S. miescheriana was observed within cox1 since each newly obtained sequence represented a unique haplotype. The comparison made using S. miescheriana isolates from Italian and Japanese wild boar and Chinese domestic pig revealed the genetic similarity of the samples depending on their geographical distances. The current study provides the first detection of Sarcocystis infection in wild boars from Latvia and molecular characterization of S. miescheriana.