Publication date: Jul 01, 2024

There are no other bovine coronavirus (BCoV) infection models except calves, which makes efficacy evaluation of vaccines and pathogenic mechanism research of BCoV inconvenient owing to their high value and inconvenient operation. This study aimed to establish a mouse model of BCoV infection. BCoV was used to infect 4-week-old male BALB/c mice and the optimal infection conditions were screened, including the following infection routes: gavage, intraperitoneal injection, and tail vein injection at doses of 1 cD7 10 TCID, 2 cD7 10 TCID and 4 cD7 10 TCID. Using the optimal infection conditions, BALB/c mice were infected with BCoV, and their body weight, blood routine, inflammatory factors, autopsy, virus distribution, and viral load were measured at 1, 3, 5, and 7 days after infection. The results showed that the optimal conditions for infecting BALB/c mice with BCoV HLJ-325 strain were continuous oral gavage for 3 days with a dose of 4 cD7 10 TCID. On the 7th day after infection, there was significant extensive consolidation of the lungs and thinning of the colon wall. Significant inflammation was observed in various organs, especially in the colon and alveoli, where a large number of inflammatory cells infiltrate. Both BCoV Ag and nucleic acid are positive in visceral organs. The viral load in the colon and lungs was significantly higher than that in the other organs (p

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