engleski

Circulation and phylogenetic relationship of chicken and turkey-origin astroviruses detected in domestic ducks (Anas platyrhynchos domesticus)

The natural occurrence of chicken and turkey- origin astroviruses in domestic ducks (Anas platyrhynchos domesticus) is described. Twenty-two duck flocks were covered by this research. The liver, spleen, kidney and intestines were sampled and tested by RT-PCR for the presence of avian nephritis virus (ANV), chicken astrovirus (CAstV), turkey astrovirus-1 (TAstV-1), turkey astrovirus-2 (TAstV-2) and duck astrovirus (DAstV). The astrovirus infection was confirmed in multiple organ samples from 68.1% of tested flocks. CAstV was detected in one flock, TAstV-2 in three and ANV in ten flocks. The molecular and phylogenetic analysis of the small ORF 1b fragment (130 nt) of all chicken and turkey-origin astroviruses detected in ducks showed that ANV-sequence group was more distant from CastV, TAstV-1 and TAstV-2 sequences, that formed a separate, more related group. ANV sequences were divided in three subgroups, suggesting that several types of ANV were detected to circulate in Croatian duck flocks. The comparison of the partial ORF 1b (254 nt) duck ANV sequences with 21 ANVs detected in various avian species (chickens, turkeys, geese, guinea fowl and pigeons) revealed they shared the higher nucleotide (95.6-97.2%) and amino acid identity (98.8-100%) with two ANV-2-like sequences from chickens (GA-SEP-A451-05 and GA-CK-SEP ANV- 364- 2005). Phylogenetic Neighbour-joining tree based on the same nucleotide alignment, and performed using the Jukes-Cantor method, clustered compared sequences in three groups. All analysed duck ANV sequences showed close phylogenetic relationship with chicken- origin ANVs. Additional work is required to determine the significance and pathogenicity of chicken and turkey-origin astroviruses in domestic ducks.

avian astroviruses ; domestic duck ; phylogenetic relationship

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