Abstract: To observe the expression levels of DEV NP gene in the various organizations of 15-day-old ducklings infected intramuscularly with virulent DEV strain GZ, SYBR GreenⅠreal-time quantitative PCR was used to detect the transcripts expression levels of NP gene. The results indicated that the NP gene could be detected in six tissues including liver, spleen, brain, thymus, kidney and lung at 3 h post-infecion (PI), and in duodenum and cecum beside the above six tissues at 6 h PI, then in pectoral muscle and cardiac muscle beside the above eight tissues at 10 h PI. The expression levels detected were various in different organizations, and reached a peak at 30 h or 48 h PI, continuing until 96 h, then all declined. These results provided a theoretical basis for clarification of pathogenic mechanism of DEV, and made the foundation for the study of the relationship between pathogen and ducks．

Key words: duck plague, nucleocapsid protein gene, real-time PCR, ducklings