Sarcocystis species are protozoan parasites with complex life cycles that require both predator and prey hosts. Despite their significance, little is known about the prevalence and diversity of Sarcocystis in dog feces worldwide. This study aimed to determine the presence of Sarcocystis in domestic dogs in Egypt and to identify the species involved using a combination of parasitological and molecular approaches. Fecal samples from 100 domestic dogs were collected and examined for Sarcocystis oocysts or sporocysts using a sugar flotation method. DNA was extracted from 30 of these samples, and a fragment of the 18S rRNA gene was amplified through PCR, followed by sequencing to confirm species identity. Microscopic examination detected Sarcocystis in 4% of samples. PCR and sequence analysis confirmed infection in 16 out of 30 dogs (53.3%). There was no significant association between infection prevalence and the age or sex of the animals. Sporocysts measured 13.2–16.0 × 9.4–11 μm. Sequence comparison revealed 99.82% similarity with Sarcocystis tenella previously reported in sheep from Iraq and Iran. This study provides the first molecular evidence that domestic dogs in Egypt can serve as definitive hosts for S. tenella. These results contribute important information for future epidemiological research and may aid in developing control strategies against sarcocystosis in livestock and dogs.
