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Several cases of gastrointestinal symptoms including diarrhea and vomiting due to the consumption of Sarcocystis-infected venison have been reported in Japan. However, the control of case incidence is difficult, as epidemiological information concerning Sarcocystisin venison in Japan is insufficient. We examined the prevalence and parasite load of Sarcocystisin 89 samples of Yezo-deer (Cervus nippon yesoensis) venison in Hokkaido by quantifying the copy numbers of the 18S rRNA gene of Sarcocystis, followed by a statistical analysis that considered the sampling area, age, and sex to clarify the parameters related to the parasite load. The copy numbers per gram of venison in samples ranged from 4.8 to 8.8 log. Wilcoxon rank-sum test, the one-way factorial analysis of variance (ANOVA), Steel–Dwass test, and a two-way factorial ANOVA showed significant differences in the copy numbers among sampling areas, not by age or sex, suggesting that the load of Sarcocystisin wild deer depended on the sampling area in Hokkaido. Notably, more than 80% of Hokkaido venison has a higher gene copy number than the meat that caused Sarcocystis fayeri-food poisoning. This information is expected to contribute to the establishment of hygiene standards for safe venison consumption and the control of gastrointestinal symptom cases due to consumption of Sarcocystis-infected venison.

Recently, horse meat (basashi) contaminated with Sarcocystisspp. caused food poisoning in Japan. An official detection method provided by the Ministry of Health, Labour and Welfare (MHLW), Japan, was designed to detect Sarcocystis fayerito diagnose and control outbreaks of basashifood poisoning. In 2011, Sarcocystis-contaminated venison also caused food poisoning. However, the official MHLW detection method was not adequate for detecting Sarcocystisspp. in venison. In this study, we established a novel PCR-based detection method that amplifies 18S rRNA gene based on the conserved region of the sequence in 32 species of Sarcocystisfor screening and quantification. Fifty venison samples from three areas in Hokkaido were examined by the MHLW method and the novel detection method. All samples were Sarcocystisspp.-positive. A sequence analysis indicated the presence of a species of Sarcocystisspecific to sika deer (Cervus nippon), and not to horses. Another primer pair was designed for a quantitative real-time PCR assay to determine the copy number of the Sarcocystis-18S rRNA gene in parasitized venison. The melting curve analysis revealed high specificity of this assay. The calculated curve demonstrated that this quantitative PCR assay showed R2value of 0.993 with 10–106copies. Using this quantitative real-time PCR assay, the gene copy numbers were determined in 50 venison samples. The copy numbers of each sample ranged from 104to 107per gram. The copy numbers differed according to the area in Hokkaido. This indicates that the density of Sarcocystisspp. that infect Sika deer in Hokkaido is affected by the area. The novel screening and quantitative PCR method for Sarcocystisin venison was useful for collecting epidemiological information on Sarcocystisin wild Japanese sika deer, which will contribute to improve the safety of venison products in Japan.