Identification And Sequence Analysis Of P1 Gene Of Duck Hepatitis A Virus Type 3 Strains Isolated From Linyi Of Shandong Province

Duck viral hepatitis(DVH) is an acute, rapidly spreading and widely distributed disease of ducklings. The mortality of the duck flock was more than 90%. In the present, DHAV is becoming a worldwide in distribution and one of the most economic importance diseases. Corresponding to the three genotypes A, B and C by neutralization tests, DHAVs had been classified into three serotypes: the classical serotype 1(DHAV-1), a serotype recently isolated in Taiwan(DHAV-2) and the recently described serotype isolated in South Korea and China. There is no cross-neutralization between DHAV-1 and DHAV-2 and limited cross-neutralization between DHAV-1 and DHAV-3. This research consists of three parts as follows:Part 1, Isolation and RT-PCR Identification of the 48 DHAV-3 isolatesIn this study, hepatitis samples were collected from Linyi of Shandong province from 2012 to 2013, Epidemic materials were gringed to infect 11-day-old embryonated duck eggs and 45 allantoic fluid of dead embryonated eggs were harvested. The\allantoic fluid harvested were injected to five 3-days-old goose of cheeper duck in muscule with 2.0 ml each, The infected ducks began to dead and presented a typical clinical symptoms and pathological changes of duck hepatitis a virus after 24 hours. We designed specific primers respectively according to the DNA sequence of Duck Hepatitis A Virse type 3 published in the Gen Bank for RT-PCR amplification, and 48 strains were isolated to be DHAV-3.Part 2, Sequence analysis of P1 gene of duck hepatitis A virus type 3 isolated from Linyi of Shandong provinceIn this study, P1 gene of 7 virulent DHAV-3 strains isolated from Shandong province of China in 2012~2013 were sequenced and analyzed. The results showed that all the P1 genes of the 7 strains show a high degree of homogy, with nucleotide identities of 98.6%~99.8% and amino acid identities of 99.6%~100%. Phylogenetic analysis showed that the P1 gene ofDHAV-3 had obvious geographical characteristics.