Molecular Characterization of <i>Eimeria</i> Species in Captive Japanese Serows <i>(Capricornis crispus )</i>

Eimeria is a coccidiosis-causing parasitic protozoa belonging to the phylum Apicomplexa.Although many studies have been conducted on coccidiosis in livestock and poultry, only a few have focused on wild and zoo-raised animals.Japanese serows (Capricornis crispus), belonging to the Bovidae family, hold special natural monument status in Japan.Previous studies have reported the morphological characteristics of Eimeria in Japanese serows; however, there have been no reports on their genetic phylogeny.In this study, we examined the morphological and genetic characteristics of Eimeria in Japanese serows kept at the Kanazawa Zoological Gardens, Kanagawa, Japan.Fecal samples collected from Japanese serows in the target zoos in 2021 and 2022 were used.Morphometric analyses of the oocysts were performed microscopically, followed by an examination of the 18S rDNA gene sequence of Eimeria.Eimeria oocysts were detected in five of the seven fecal samples (71.4%).Genetic analysis revealed that they formed the same group as Eimeria in ruminants, with a high homology rate of >98%.Eimeria in Japanese serows was classified into two groups, with a genetic pairwise differences of 0.021-0.011.Further genetic phylogeny may help to identify species of the Eimeria genus in serows.