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One-year molecular survey of astrovirus infection in turkeys in Poland.

Domanska-Blicharz K, Seroka A, Minta Z - Arch. Virol. (2011)

Bottom Line: Phylogenetic analysis revealed genetic variability in the TAstV strains that were isolated.Some of Polish TAstV-2 strains were genetically related to the North American isolates; however, most of them formed a distinct subgroup of "European" isolates, suggesting their separate origin or evolution.Additionally, due to the high variability of the TAstV sequences, the most suitable method for TAstV typing seems to be sequencing.

View Article: PubMed Central - PubMed

Affiliation: Department of Poultry Diseases, National Veterinary Research Institute, Al. Partyzantow 57, 24-100 Pulawy, Poland. domanska@piwet.pulawy.pl

ABSTRACT
The presence of turkey astrovirus (TAstV) was monitored in meat-type turkey flocks in Poland in 2008. Clinical samples (10 individual faecal swabs/flock) from 77 flocks aged 1-19 weeks were collected from different regions of the country. RT-PCR experiments were performed for detection and molecular characterization of TAstV using four sets of primers within the RdRp gene (ORF1b). The prevalence of astrovirus was 34/77 (44.15%) in the flocks tested. TAstV type 2 was associated with 30 of 77 infections (38.9%), either alone or in mixed infections; TAstV type 1 was detected in 9 of 77 flocks (11.6%), either alone or in mixed infections; ANV was detected only in one flock (1.29%) by sequence analysis during this study. Phylogenetic analysis revealed genetic variability in the TAstV strains that were isolated. Some of Polish TAstV-2 strains were genetically related to the North American isolates; however, most of them formed a distinct subgroup of "European" isolates, suggesting their separate origin or evolution. Additionally, due to the high variability of the TAstV sequences, the most suitable method for TAstV typing seems to be sequencing.

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Phylogenetic tree of nucleotide sequences of the ORF1b gene of TAstV. Sequences are identified by country/origin/code/year and are described in “Materials and methods”. Sequences indicated by a black dot are from the present study, and those that are underlined are strains that were used as references. The phylogenetic tree was constructed using the neighbor-joining algorithm and the maximum-likelihood model with 1000 bootstrap replicates (bootstrap values shown on tree)
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Fig1: Phylogenetic tree of nucleotide sequences of the ORF1b gene of TAstV. Sequences are identified by country/origin/code/year and are described in “Materials and methods”. Sequences indicated by a black dot are from the present study, and those that are underlined are strains that were used as references. The phylogenetic tree was constructed using the neighbor-joining algorithm and the maximum-likelihood model with 1000 bootstrap replicates (bootstrap values shown on tree)

Mentions: Polish avian astrovirus isolates are divided into three groups (Fig. 1): TAstV-1-like, TAstV-2-like and ANV-like. Most of them belong to the TAstV-2 type. These isolates formed two subgroups (subgroups 1 and 2), with the majority being in subgroup 2 (17 isolates). In subgroup 1, three subclades (a, b, c) could be differentiated, and all six Polish isolates clustered in one subclade (a) together with astroviruses previously reported from the USA. Subclade b included strains from the USA, Italy and France that were isolated either from turkey or guinea fowl; however, the latter formed separate sublineages. Subclade c included strains only from the USA. A comparison of nucleotide and amino acid sequences of six Polish turkey astrovirus type 2 strains from subgroup 1, showed 93.5-99.5% and 96.8-98.9% similarity to each other and 86.9-91.2 and 93.5-96.8% to the prototype TAstV-2 isolate CA/00. Subgroup 2 TAstVs did not show any distinct subclades and included only European isolates from Poland and Italy. Comparison of a 366-nucleotide region of ORF1b (from nt 4136 to 4502 of the TAstV-2 genome) revealed that, among these isolates, nt identity was between 96.9 and 100%, and deduced amino acid identity was between 97.6% and 100%. In turn, nucleotide and amino acid similarity of this subgroup to the prototype TAstV-2 was 89.5-90.6% and 95.3-96.5%, respectively. Indeed, these isolates formed a separate subgroup, but its distinction was rather weakly supported statistically (bootstrap value 60).Fig. 1


One-year molecular survey of astrovirus infection in turkeys in Poland.

Domanska-Blicharz K, Seroka A, Minta Z - Arch. Virol. (2011)

Phylogenetic tree of nucleotide sequences of the ORF1b gene of TAstV. Sequences are identified by country/origin/code/year and are described in “Materials and methods”. Sequences indicated by a black dot are from the present study, and those that are underlined are strains that were used as references. The phylogenetic tree was constructed using the neighbor-joining algorithm and the maximum-likelihood model with 1000 bootstrap replicates (bootstrap values shown on tree)
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3104002&req=5

Fig1: Phylogenetic tree of nucleotide sequences of the ORF1b gene of TAstV. Sequences are identified by country/origin/code/year and are described in “Materials and methods”. Sequences indicated by a black dot are from the present study, and those that are underlined are strains that were used as references. The phylogenetic tree was constructed using the neighbor-joining algorithm and the maximum-likelihood model with 1000 bootstrap replicates (bootstrap values shown on tree)
Mentions: Polish avian astrovirus isolates are divided into three groups (Fig. 1): TAstV-1-like, TAstV-2-like and ANV-like. Most of them belong to the TAstV-2 type. These isolates formed two subgroups (subgroups 1 and 2), with the majority being in subgroup 2 (17 isolates). In subgroup 1, three subclades (a, b, c) could be differentiated, and all six Polish isolates clustered in one subclade (a) together with astroviruses previously reported from the USA. Subclade b included strains from the USA, Italy and France that were isolated either from turkey or guinea fowl; however, the latter formed separate sublineages. Subclade c included strains only from the USA. A comparison of nucleotide and amino acid sequences of six Polish turkey astrovirus type 2 strains from subgroup 1, showed 93.5-99.5% and 96.8-98.9% similarity to each other and 86.9-91.2 and 93.5-96.8% to the prototype TAstV-2 isolate CA/00. Subgroup 2 TAstVs did not show any distinct subclades and included only European isolates from Poland and Italy. Comparison of a 366-nucleotide region of ORF1b (from nt 4136 to 4502 of the TAstV-2 genome) revealed that, among these isolates, nt identity was between 96.9 and 100%, and deduced amino acid identity was between 97.6% and 100%. In turn, nucleotide and amino acid similarity of this subgroup to the prototype TAstV-2 was 89.5-90.6% and 95.3-96.5%, respectively. Indeed, these isolates formed a separate subgroup, but its distinction was rather weakly supported statistically (bootstrap value 60).Fig. 1

Bottom Line: Phylogenetic analysis revealed genetic variability in the TAstV strains that were isolated.Some of Polish TAstV-2 strains were genetically related to the North American isolates; however, most of them formed a distinct subgroup of "European" isolates, suggesting their separate origin or evolution.Additionally, due to the high variability of the TAstV sequences, the most suitable method for TAstV typing seems to be sequencing.

View Article: PubMed Central - PubMed

Affiliation: Department of Poultry Diseases, National Veterinary Research Institute, Al. Partyzantow 57, 24-100 Pulawy, Poland. domanska@piwet.pulawy.pl

ABSTRACT
The presence of turkey astrovirus (TAstV) was monitored in meat-type turkey flocks in Poland in 2008. Clinical samples (10 individual faecal swabs/flock) from 77 flocks aged 1-19 weeks were collected from different regions of the country. RT-PCR experiments were performed for detection and molecular characterization of TAstV using four sets of primers within the RdRp gene (ORF1b). The prevalence of astrovirus was 34/77 (44.15%) in the flocks tested. TAstV type 2 was associated with 30 of 77 infections (38.9%), either alone or in mixed infections; TAstV type 1 was detected in 9 of 77 flocks (11.6%), either alone or in mixed infections; ANV was detected only in one flock (1.29%) by sequence analysis during this study. Phylogenetic analysis revealed genetic variability in the TAstV strains that were isolated. Some of Polish TAstV-2 strains were genetically related to the North American isolates; however, most of them formed a distinct subgroup of "European" isolates, suggesting their separate origin or evolution. Additionally, due to the high variability of the TAstV sequences, the most suitable method for TAstV typing seems to be sequencing.

Show MeSH
Related in: MedlinePlus