| Summary: | 博士 === 國立中興大學 === 微生物暨公共衛生學研究所 === 103 === Waterfowl parvovirus infection is a highly contagious and fatal disease of goslings and ducklings. According to host specificity and viral nucleotide sequences, waterfowl parvoviruses are divided into two groups: the goose parvovirus (GPV) group and the Muscovy duck parvovirus (MDPV) group. Two major outbreaks of waterfowl parvovirus infection occurred in Taiwan in the last three decades. The first was caused by GPV whereas the second by MDPV. In Taiwan, a live attenuated vaccine strain is available for the control of GPV, but no vaccine strain is available for MDPV. The lack of vaccine strain hampers the control of MDPV.
Infectious clone methodology is a valuable tool to study the pathogenic mechanisms of parvoviruses, but no infectious clone of MDPV is yet available. In this study, a plasmid clone containing the full-length genome of MDPV was constructed using the TA cloning methodology. This MDPV clone was found to be infectious after transfection of primary Muscovy duck embryo fibroblast cells and passage in embryonated Muscovy duck eggs. Site-directed mutagenesis showed that the K75N mutation in the VP1 protein of MDPV resulted in the partial attenuation of the virus.
Previous study shows that GPV causes the disease in both geese and Muscovy ducks whereas MDPV causes the disease only in ducks but not in geese. In this study, the white Roman geese were experimentally inoculated with MDPV. PCR analysis showed that the geese inoculated with MDPV shed virus from cloacalafter inoculation. Western blot analysis showed that the geese inoculated with MDPV produced antibodies against MDPV. Taken together, these results indicated that the white Roman goose is a host for infection and viral shedding of MDPV.
In summary, this studydevelops a simple method for constructing infectious clone of MDPV and this method can facilitate development of vaccines against diseases caused by MDPV. Further, this study also demonstrates that MDPV infection occurred not only in ducks but also in geese. These results are important for the control of waterfowl parvovirus infection in the field.
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