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Genetic Variability of Bovine Viral Diarrhea Virus and Evidence for a Possible Genetic Bottleneck during Vertical Transmission in Persistently Infected Cattle.

Dow N, Chernick A, Orsel K, van Marle G, van der Meer F - PLoS ONE (2015)

Bottom Line: Viral variants were clustered by tissue compartment significantly more often than expected by chance alone with the central nervous system appearing to be a particularly important viral reservoir.We also found strong indications for a genetic bottleneck during vertical transmission from PI animals to their offspring.These quasispecies analyses within PI cattle exemplify the role of the PI host in viral propagation and highlight the complex dynamics of BVDV pathogenesis, transmission and evolution.

View Article: PubMed Central - PubMed

Affiliation: Department of Ecosystem and Public Health, Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta, Canada.

ABSTRACT
Bovine viral diarrhea virus (BVDV), a Pestivirus in the family Flaviviridae, is an economically important pathogen of cattle worldwide. The primary propagators of the virus are immunotolerant persistently infected (PI) cattle, which shed large quantities of virus throughout life. Despite the absence of an acquired immunity against BVDV in these PI cattle there are strong indications of viral variability that are of clinical and epidemiological importance. In this study the variability of E2 and NS5B sequences in multiple body compartments of PI cattle were characterized using clonal sequencing. Phylogenetic analyses revealed that BVDV exists as a quasispecies within PI cattle. Viral variants were clustered by tissue compartment significantly more often than expected by chance alone with the central nervous system appearing to be a particularly important viral reservoir. We also found strong indications for a genetic bottleneck during vertical transmission from PI animals to their offspring. These quasispecies analyses within PI cattle exemplify the role of the PI host in viral propagation and highlight the complex dynamics of BVDV pathogenesis, transmission and evolution.

No MeSH data available.


Related in: MedlinePlus

Example consensus network based on the E2 (A) and NS5B (B) gene fragment posterior tree sets for PI8.Tips are coloured according to their tissue of origin (tonsil = yellow, colon = green, MLN = blue, obex = purple, serum = orange, ileum = teal).
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pone.0131972.g003: Example consensus network based on the E2 (A) and NS5B (B) gene fragment posterior tree sets for PI8.Tips are coloured according to their tissue of origin (tonsil = yellow, colon = green, MLN = blue, obex = purple, serum = orange, ileum = teal).

Mentions: Consensus networks largely agree with the more recent branching patterns seen in consensus trees but differ in the more ancestral events (Fig 3, S4 and S5 Figs). The networks display a star-like pattern of evolution which is consistent with the introduction of a small, homogenous population of viral particles that rapidly spread to infect different body compartments prior to any significant genetic drift or mutation. Although the support for the splits in these networks (not shown for clarity) is not necessarily higher than the support shown on the trees, the networks are able to display more potential evolutionary relationships rather than just one. This makes them more suitable for evaluating instances like this where there are multiple, reasonable evolutionary events detected using Bayesian phylogenetics.


Genetic Variability of Bovine Viral Diarrhea Virus and Evidence for a Possible Genetic Bottleneck during Vertical Transmission in Persistently Infected Cattle.

Dow N, Chernick A, Orsel K, van Marle G, van der Meer F - PLoS ONE (2015)

Example consensus network based on the E2 (A) and NS5B (B) gene fragment posterior tree sets for PI8.Tips are coloured according to their tissue of origin (tonsil = yellow, colon = green, MLN = blue, obex = purple, serum = orange, ileum = teal).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4488595&req=5

pone.0131972.g003: Example consensus network based on the E2 (A) and NS5B (B) gene fragment posterior tree sets for PI8.Tips are coloured according to their tissue of origin (tonsil = yellow, colon = green, MLN = blue, obex = purple, serum = orange, ileum = teal).
Mentions: Consensus networks largely agree with the more recent branching patterns seen in consensus trees but differ in the more ancestral events (Fig 3, S4 and S5 Figs). The networks display a star-like pattern of evolution which is consistent with the introduction of a small, homogenous population of viral particles that rapidly spread to infect different body compartments prior to any significant genetic drift or mutation. Although the support for the splits in these networks (not shown for clarity) is not necessarily higher than the support shown on the trees, the networks are able to display more potential evolutionary relationships rather than just one. This makes them more suitable for evaluating instances like this where there are multiple, reasonable evolutionary events detected using Bayesian phylogenetics.

Bottom Line: Viral variants were clustered by tissue compartment significantly more often than expected by chance alone with the central nervous system appearing to be a particularly important viral reservoir.We also found strong indications for a genetic bottleneck during vertical transmission from PI animals to their offspring.These quasispecies analyses within PI cattle exemplify the role of the PI host in viral propagation and highlight the complex dynamics of BVDV pathogenesis, transmission and evolution.

View Article: PubMed Central - PubMed

Affiliation: Department of Ecosystem and Public Health, Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta, Canada.

ABSTRACT
Bovine viral diarrhea virus (BVDV), a Pestivirus in the family Flaviviridae, is an economically important pathogen of cattle worldwide. The primary propagators of the virus are immunotolerant persistently infected (PI) cattle, which shed large quantities of virus throughout life. Despite the absence of an acquired immunity against BVDV in these PI cattle there are strong indications of viral variability that are of clinical and epidemiological importance. In this study the variability of E2 and NS5B sequences in multiple body compartments of PI cattle were characterized using clonal sequencing. Phylogenetic analyses revealed that BVDV exists as a quasispecies within PI cattle. Viral variants were clustered by tissue compartment significantly more often than expected by chance alone with the central nervous system appearing to be a particularly important viral reservoir. We also found strong indications for a genetic bottleneck during vertical transmission from PI animals to their offspring. These quasispecies analyses within PI cattle exemplify the role of the PI host in viral propagation and highlight the complex dynamics of BVDV pathogenesis, transmission and evolution.

No MeSH data available.


Related in: MedlinePlus