The complete mitochondrial genome of Eimeria anseris from the wintering greater white-fronted goose in Shengjin Lake, China, and phylogenetic relationships among Eimeria species.

Coccidiosis is recognized as one of the most widespread and pathogenic parasitic infections in migratory waterfowl throughout the world. It can be caused by several species of Eimeria. We sequenced the complete mitochondrial genome (mtDNA) of Eimeria anseris from wintering greater white-fronted geese (Anser albifrons) in China. The complete E. anseris mtDNA is 6179 bp in size and contains three protein-coding genes (CYT B, COI, and COIII), 12 gene fragments for large subunit ribosomal RNA (rRNA), and seven gene fragments for small subunit rRNA, but no transfer RNA genes. Available complete Eimeria mtDNA sequences are highly conserved in sequence: the sequences are all similar in length; with the same three protein-coding genes and fragmented rRNA genes; ATG is generally the start codon, and TAA and TAG are the most frequently used stop codons. Our molecular phylogenetic analyses show some species clustering into host-specific clades, but many species do not follow clear coevolutionary host segregating patterns. The results suggest that Eimeria spp. from turkeys and chickens are paraphyletic groups, while Eimeria species isolated from rabbits are a monophyletic group. E. anseris, which infects A. albifrons, and another group of Eimeria isolated from chickens form a closely related monophyletic clade.