Coccidiosis caused by Eimeria is one of the most common and significant diseases in goats, leading to serious economic losses in the development of the goat industry. Although several genetic loci, such as 18S rDNA, ITS-1, ITS-2, and COI, have been applied in the molecular characterization of Eimeria in chicken, rabbits, turkey, and wildlife, little is known about these molecular markers of Eimeria in goats. In the present study, we isolated purified oocysts of highly pathogenic Eimeriaarloingi and Eimeria christenseni from fecal samples of goats in Shaanxi province, China, and then subjected these purified oocysts to genomic DNA isolation, PCR amplification, and sequencing of 18S rDNA, ITS-1, ITS-2, and COI loci of Eimeria arloingi and Eimeria christenseni. Finally, the obtained sequences were used for phylogenetic analysis of Eimeria species in goats and other livestock. The lengths of the 18S rDNA, ITS-1, ITS-2, and COI were 1790 bp, 403 bp, 584 bp, and 1268 bp for E. arloingi and 1796 bp, 386 bp, 565 bp, and 1268 bp for E. christenseni, respectively. The phylogenetical analysis based on 18S rDNA indicated that E. christenseni and E. arloingi were the most closely related to ovine Eimeria, followed by E. bovis, E. ellipsoidalis, and E. zuernii from cattle. The phylogenetical analysis based on ITS-1 and ITS-2 could not effectively distinguish ovine Eimeria from caprine Eimeria. The phylogenetical analysis based on the COI locus could effectively distinguish between Eimeria species from goats and cattle, but it was ineffective in distinguishing between Eimeria species from sheep and goats. To the best of our knowledge, this is the first characterization of 18S rDNA, ITS-1, ITS-2, and COI in E. arloingi and E. christenseni; it can provide useful genetic markers for molecular epidemiological and population genetic studies on E. arloingi and E. christenseni in goats and contribute to the prevention and control of goat coccidiosis.
Keywords: 18S rDNA; COI; Eimeria arloingi; Eimeria christenseni; ITS; goats.