The invention discloses a
circular RNA (Ribonucleic Acid) and an application of the
circular RNA in a trichomonad pigeon vaccine. The coding element contained in the
circular RNA can be used for coding the recombinant
trichomonas pigeon AP33 or AP65
protein. The coding element has a sequence as shown in SEQ ID NO.1 or SEQ ID NO.2 or a conservative variant sequence of the sequence as shown in SEQ ID NO.1 or SEQ ID NO.2. The circular
RNA can induce
protein expression in an
animal body and generate a high-level
antibody, does not contain infectious
insect species components, can be degraded into nucleotides in the body and cannot be integrated into a
host genome when being applied to a trichomonad pigeon vaccine, has no risk to pigeons in use, can stimulate the pigeons to generate relatively strong immune responses including
humoral immunity and
cellular immunity, and can be used for preparing a vaccine for preventing and treating the pigeons. Meanwhile, the vaccine is high in stability, can be prepared on a large scale through a molecular technology, and is low in production cost.