| Cross-transmission experiments were done with Eimeria arizonensis from Peromyscus truei and P. maniculatus , and 2 species whose sporulated oocysts are morphologically similar to those of E. arizonensis: E. albigulae from Neotoma albigula, and E. onychomysis from Onychomys leucogaster. Isolates of each species were inoculated into P. maniculatus and the latter 2 host species. Eimeria arizonensis was transmitted only to P. maniculatus ; likewise, E. albigulae and E. onychomysis successfully infected only N. albigula and O. leucogaster, respectively. These results indicate that E. arizonensis, E. albigulae and E. onychomysis are distinct species that are not transmissible between the genera of their respective hosts.; In addition, E. arizonensis, E. albigulae and E. onychomysis were distinguished using ITS1 sequences obtained from multiple isolates of each species. ITS1 sequences also were obtained from 6 other coccidian species from murid rodents: E. falciformis, E. langebarteli, E. nieschulzi, E. papillata, E. separata and E. sevilletensis , and E. reedi, from heteromyid rodents. Parsimony and maximum likelihood analyses of the sequences found that the isolates of E. arizonensis, E. albigulae and E. onychomysis belonged to closely related, but distinct, clades. Maximum likelihood pairwise distances between these species ranged from 7--12%, and distances within each species ranged from <1--5%; it is suggested that ITS1 genetic distances may facilitate the differentiation of Eimeria species that produce morphologically similar sporulated oocysts. Thus, ITS1 sequencing provides data which can be used for taxonomic and phylogenetic studies of the genus Eimeria.; The 18S rDNA genes of the 10 Eimeria species listed above were PCR amplified, digested with 12 restriction endonucleases, and analyzed with agarose electrophoresis. The resulting fragment patterns (riboprints) distinguished all species except E. sevilletensis from E. falciformis, and E. arizonensis from E. albigulae. Distance and parsimony analyses of the restriction fragment data produced a clade containing E. arizonensis, E. albigulae, E. onychomysis, E. reedi and E. papillata. This and other results of the riboprinting study concurred with those from the ITS1 sequence analyses, and previous phylogenetic work on these parasites. Like ITS1 sequencing, riboprinting appears to be useful for taxonomic and phylogenetic studies of eimerian species. |
