Detection And Sequence Analysis Of Duck Circovirus In Sick Ducks With Short Beak And Dwarfism Syndrome

Since the second half of 2014,Cherry Valley Ducks in Shandong,Anhui and other places were been infected with a disease,named short beak and dwarfism syndrome(BADS),characteristed with large tongue,short beak,tongue extension and swelling.In the later stage of infection,the fractures of the tibia and the wing bone were easy to occur,weight was significantly lower than that of healthy ducks,which leads to the passing rate of ducks decline,resulting in greater economic losses.The pathogen was identified as a new goose plague virus(NGPV)or GPV mutant via the isolation and identification.NGPV positive samples infected ducks,only a few ducks can reproduce with natural cases similar short beak symptoms,laboratory disease rate is low,so the occurrence of the disease is not only caused by NGPV alone,there are other pathogenic factors involved,Because this disease has the clinical symptom similar to circovirus,For example,the Beak and feather disease virus which causes the parrot's beak deformation,severe feather removal and weight loss,beak to deform,feather shed and weight loss,Goose circoviruse causes the body's short stature syndrome,Moreover,immunosuppression of Du CV that lead it has a higher rate of mixed infection with other diseases.Therefore,we suspect that the ducks with short beak and dwarfism syndrome co-infected with the duck circovirus.In order to understand the Du CV prevalence and severity in BADS ducks,to identify the genotype and sequence of Du CV and provide the basis for disease,This study will complete the following research contents:1.Detection of duck circovirus in BADS ducksWe have taken 8 organs,such as heart,liver,spleen,lung,kidney and so on from 147 dead ducks in 24 duck groups of Shandong,Jiangsu,Anhui province,and used the conventional PCR method to detect the Du CV,The results showed that the positive rate was 53.06%(78/147),the group infection rate was 83.3%(20/24),and the mixed infection rate of NGPV was 53.16%(42/79).2.Gene sequencing and sequence analysis of Du CVScreening positive samples for whole genome amplification and analysis obtained a total of 4 whole genome sequences,including two strains of genome size is 1993 nt,the other two were 1995 nt,this obtained sequences are consistent with the genome size of other strains reported.There are 3 main reading frames,V1/rep,C1/cap and C2 in the genome,and there is no insertion or deletion in the coding region of the 4 strains.According to the whole gene sequence and the phylogenetic tree of two major viral nucleotide sequences,it was also showed that the 4 sequences were type 1.