A novel Eimeria species found in the marbled polecat (Vormela peregusna)

There are no known coccidian parasites reported from the marbled polecat (<i>Vormela peregusna</i>; IUCN Vulnerable), a mustelid found in southeastern Europe and western Asia. There are eleven <i>Eimeria</i> species documented in other mustelids. This study reports a complete mitochondrial genome (mtDNA) from <i>Eimeria</i> species found in marbled polecat. Intestinal samples from seven nature-killed or road-killed individuals (collected 2020-2023 in Xinjiang, China) were subjected to genomic DNA extraction. <i>cox1</i> nested PCR screening revealed <i>Eimeria</i> infection in 3/7 hosts. Full mitochondrial genome amplification using five overlapping primer pairs yielded a 6179 bp sequence (GenBank PV393175). This mtDNA exhibits classic apicomplexan features: three protein-coding genes (<i>cytb</i>, <i>cox1</i>and <i>cox3</i>), fragmented rRNAs, and no tRNAs. The mtDNA shows high A + T bias (64.49 %). Phylogenetically, <i>Eimeria</i> isolate in marbled polecat was clustered with <i>Eimeria mephitidis</i> (bootstrap = 100 %) yet displayed significant mitogenomic divergence (only 97.65 % sequence identity), particularly in <i>cox3</i> (95.11 % <i>vs.</i> intraspecific minimum identity 95.50 %). Combined with mtDNA arrangement, significant genetic divergence and host association, we characterized a novel mitochondrial genome from an <i>Eimeria</i> species.