Molecular identification of Sarcocystis hominis and other three Sarcocystis species in cattle meat from Lithuania

Abstract

The members of genus Sarcocystis are broadly distributed parasites of mammals, birds and reptiles. These apicomplexan organisms are characterised by two-host prey-predator life cycle. Up till 2015-2016 three Sarcocystis species, S. cruzi, S. hirsuta and S. hominis were known to form sarcocysts in cattle muscles. Nowadays, six species are characterised in these hosts, including S. bovini, S. bovifelis and S. heydorni. It should be noted that humans are definitive hosts of S. hominis and S. heydorni. Out of these two species, S. hominis was identified worldwide, causing nausea, vomiting, diarrhea and other intestinal disorders. Due to changes in the classification of Sarcocystis species in cattle, high S. hominis infection prevalence recorded is likely misleading. S. hominis might be misidentified because of morphological similarity with S. bovini and S. bovifelis. Furthermore, molecular data on S. hominis is still lacking. In 2018-2019, 102 diaphragm muscle samples of cattle bred in Lithuania were examined for Sarcocystis. Using meat trypsinisation, species-specific PCR targeting cox1 and sequencing 100% of samples were positive for Sarcocystis. Four Sarcocystis species, S. cruzi (96.1%), S. bovifelis (71.6%), S. hirsuta (30.4%) and S. hominis (13.7%) were identified. Co-infections were frequently observed (75.5%): mostly, two species were diagnosed in the same sample (44.1%), followed by three (26.5%) and four (4.9%). Further researches on S. hominis epidemiology in various regions are ...[...].