OBJECTIVE: To analyze the distribution law, detoxification and antibody changes of mouse parvovirus (MVM) in artificially infected mice, and the situation of mice infected with MVM under natural conditions.
Methods: 33 BALB/c mice were intraperitoneally inoculated with 0.2 mL MVM suspension. The appearance, behavior, diet and mental state of the animals were observed every day. Two to three animals were treated at 12 time points on the 0th to 60th day of inoculation. Euthanasia was performed, and tissue, stool, and serum samples were taken for testing. Quantitative PCR (QPCR) was used to detect viral nucleic acid in tissues and feces, and ELISA was used to detect serum antibodies. At the same time, 100 SPF mice and 76 open-feeding mice were used to detect MVM nucleic acid, and 1463 SPF mice and 82 open-feeding mice were used to detect MVM antibodies.
RESULTS: The appearance, behavior, diet and mental state of the experimental mice were not abnormal after inoculation with MVM, and there were no obvious lesions at autopsy. Viral nucleic acid could be detected in all tissues after inoculation, and peaked at 4-7 days after inoculation, and viral nucleic acid could still be detected at 60 days. Compared among tissues, the tissues with the highest virus peak were liver, followed by kidney, spleen, stomach, heart, lung, cecum and brain. Fecal excretion peaked at 11 days after inoculation, and then decreased rapidly, but could still be detected at 60 days. Serum antibodies began to be produced 7 days after virus inoculation, and then the antibody titer gradually increased, reaching about 32 times on 21 days, and then at about 64 times until 60 days. Among the clinical samples, nucleic acid detection in SPF mice was not detected, and the positive rate of open feeding mice was 14.5%, which was confirmed to be MVM virus infection after sequencing comparison; antibody detection in SPF mice had a lower detection rate (0.3%) , the detection rate of open feeding mice was 68.3%.
Conclusion: MVM infection in mice is generally in a state of latent infection, which can be detoxified for a long time. The main tissue organs, feces and serum can be used for the detection of MVM. MVM infection in experimental mice can be detected by viral nucleic acid and serum antibody detection methods. detection.