Morphological and molecular phylogenetic analyses of the apicomplexan parasites, Eimeria media and Eimeria stiedai, infecting the domestic rabbits, Oryctolagus cuniculus

The eimerian infection is one of the most serious infections that can decrease rabbit productivity since it can lead to serious diseases. There is little information about Eimeria media and Eimeria stiedai infections in Saudi Arabia, and molecular data is particularly weak. To establish the prevalence, morphological and molecular characterization of E. media and E. stiedai isolated from spontaneously infected rabbits, the current study was conducted. Ten healthy rabbits, Oryctolagus cuniculus, whose feces were collected and kept at the laboratory were examined for protozoan parasite infection using the floatation method. Purified oocysts were used to extract DNA, which was then used in a polymerase chain reaction (PCR) with primers that amplified a partial sequences of the 18S rDNA gene. Seven rabbits had coinfections with two eimerian species. Sporulated oocysts of E. media had an obvious micropyle and were oval, measuring 24.92-30.03 (28.04) lm in length and 16.33-19.63 (18.31) lm in width. In contrast, E. stiedai were ellipsoid and measured 31.03-36.47 (33.79) lm in length and 18.21-20.93 (19.32) lm in width. The identity of the species of Eimeria parasites detected from the host (rabbits) was verified by the results of the sequences for the 18S rDNA gene. Both organisms (E. media and E. stiedai) grouped with rabbit eimerian parasites with distinct association with the group that contains oocysts residual body. Sequences from E. stiedai revealed insertions on two sites that had never been detected in E. stiedai sequences previously deposited in GenBank. The current parasite species are closely related to the previously described and deposited E. media and E. stiedai and are deeply embedded in the genus Eimeria (family Eimeriidae). This study emphasized the significance of combining taxonomy with morphological and genetic data in the identification of Eimeria species. (c) 2023 The Author(s). Published by Elsevier B.V. on behalf of King Saud University. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).