Parasitic diseases are major trouble in many parts of the world. We consider that if a chemical can break
a DNA barcode sequence, it might be used to develop a species-specific anti-parasitic agent. To examine this hypothesis, we constructed sgRNAs that target both the control (5.8S
rDNA) and
a DNA barcode (ITS) sequence in Eimeria tenella. In vitro experiment showed that Cas9
mRNA combined with sgRNAs could reduce the sporulation percentage of oocysts and the survival rate of sporulated oocysts and sporozoites. Quantitative real-time PCR showed that the DNAs of parasites exposed to Cas9
mRNA and sgRNAs were significantly affected, regardless of whether they were exposed to a combination of two sgRNAs or just a single sgRNA. The
DNA sequencing also indicated that the experimental group exposed to two sgRNAs mixed with Cas9-induced deletion of large parts and a single sgRNA mixed with Cas9-induced mutation at sgRNA targeted fragments. In vivo trial, the effect of sgRNA and Cas9
RNA on the pathogenicity of E. tenella in chicken showed less lesion score and oocysts score (P < 0.05) in experimental groups than control groups. The results and concepts presented in this research can lead to discovering novel
nucleic acid therapeutic drugs for Eimeriasis and other
parasitic infections, which provide insights into the development of species-specific anti-parasitic agents.