Genetic and Antigenic Characterization of Avian Avulavirus Type 6 (AAvV-6) Circulating in Canadian Wild Birds (2005–2017)

Figures

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  Figure 1. Phylogenetic analysis of the whole genome sequences of AAvV-6 viruses. Viruses described in this study are denoted by red diamonds. The evolutionary history was inferred by using the Maximum Likelihood method based on the General Time Reversible model. The tree with the highest log likelihood (−61096.09) is shown. The percentage of trees in which the associated taxa clustered together is shown next to the branches. Initial tree(s) for the heuristic search were obtained automatically by applying Neighbor-Join and BioNJ algorithms to a matrix of pairwise distances estimated using the Maximum Composite Likelihood (MCL) approach, and then selecting the topology with superior log likelihood value. A discrete Gamma distribution was used to model evolutionary rate differences among sites (5 categories (+G, parameter = 0.6440)). The rate variation model allowed for some sites to be evolutionarily invariable ([+I], 31.21% sites). The tree is drawn to scale, with branch lengths measured in the number of substitutions per site. The analysis involved 26 nucleotide sequences. There were a total of 16,420 positions in the final dataset. Evolutionary analyses were conducted in MEGA X.

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  Figure 2. Phylogenetic analysis of the fusion gene sequences of AAvV-6 viruses. Viruses described in this study are denoted by red diamonds. The evolutionary history was inferred by using the Maximum Likelihood method based on the General Time Reversible model. The tree with the highest log likelihood (−6759.79) is shown. The percentage of trees in which the associated taxa clustered together is shown next to the branches. Initial tree(s) for the heuristic search were obtained automatically by applying Neighbor-Join and BioNJ algorithms to a matrix of pairwise distances estimated using the Maximum Composite Likelihood (MCL) approach, and then selecting the topology with superior log likelihood value. A discrete Gamma distribution was used to model evolutionary rate differences among sites (5 categories (+G, parameter = 0.5780)). The rate variation model allowed for some sites to be evolutionarily invariable ([+I], 31.74% sites). The tree is drawn to scale, with branch lengths measured in the number of substitutions per site. The analysis involved 42 nucleotide sequences. There were a total of 1668 positions in the final dataset. Evolutionary analyses were conducted in MEGA X.

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  Figure 3. Shedding patterns of chickens inoculated with (a) AAvV-6 strain BWTE/SK/109-1732/2016 and (b) AAvV-6 strain mallard/QC/675/2005. Oral shedding Ct values are shown in blue, cloacal shedding Ct values are shown in red.

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  Figure 4. Antigenic map developed based on cross-hemagglutination inhibition test results of AAvV-6 viruses and antisera developed to each genotype of AAvV-6. The vertical and horizontal axes represent the antigenic distance and the spacing between each grid lines represents a distance of 1 antigenic-unit distance which corresponds to a 2-fold dilution in the HI assay.