Abstract:

18S rRNA and 28S rRNA sequences of several Eimeria species from chickens and squirrels were aligned to design common primers for Eimeria parasites from various hosts based on the conserved sequences of both 3′ end of 18S rRNA and 5′ end of 28S rRNA. 1 178 bp of the ITS1-5.8S rRNA-ITS2 complete sequence of E. stiedai, including 423 bp of ITS1, 155 bp of 5.8S rRNA, and 600 bp of ITS2, was firstly cloned with the common primers and genomic DNA of oocysts of LY isolate as templates. In contrast to 5.8S rRNA fragment, ITS1 and ITS2 sequences of E. stiedai LY isolate was more variable, and less than 60% of ITS1 and ITS2 sequences of LY isolate was identical to those of Eimeria species in chickens and other rodent hosts. A sensitive and specific PCR diagnostic assay based on the ITS1-5.8S rRNA-ITS2 sequence was developed to identify E. stiedai, one of high pathogenic species from rabbits by designing specific primers for E. stiedai at the mutative sites of ITS1 and ITS2. These findings will provide a powerful tool for clinical differentiation of high pathogenic Eimeria species in rabbits and revealing population genetic characteristics of rabbit coccidia.