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Wild ducks as long-distance vectors of highly pathogenic avian influenza virus (H5N1).

Keawcharoen J, van Riel D, van Amerongen G, Bestebroer T, Beyer WE, van Lavieren R, Osterhaus AD, Fouchier RA, Kuiken T - Emerging Infect. Dis. (2008)

Bottom Line: Wild birds have been implicated in the expansion of highly pathogenic avian influenza virus (H5N1) outbreaks across Asia, the Middle East, Europe, and Africa (in addition to traditional transmission by infected poultry, contaminated equipment, and people).By experimentally infecting wild ducks, we found that tufted ducks, Eurasian pochards, and mallards excreted significantly more virus than common teals, Eurasian wigeons, and gadwalls; yet only tufted ducks and, to a lesser degree, pochards became ill or died.These findings suggest that some wild duck species, particularly mallards, can potentially be long-distance vectors of highly pathogenic avian influenza virus (H5N1) and that others, particularly tufted ducks, are more likely to act as sentinels.

View Article: PubMed Central - PubMed

Affiliation: Erasmus Medical Center, Rotterdam, the Netherlands.

ABSTRACT
Wild birds have been implicated in the expansion of highly pathogenic avian influenza virus (H5N1) outbreaks across Asia, the Middle East, Europe, and Africa (in addition to traditional transmission by infected poultry, contaminated equipment, and people). Such a role would require wild birds to excrete virus in the absence of debilitating disease. By experimentally infecting wild ducks, we found that tufted ducks, Eurasian pochards, and mallards excreted significantly more virus than common teals, Eurasian wigeons, and gadwalls; yet only tufted ducks and, to a lesser degree, pochards became ill or died. These findings suggest that some wild duck species, particularly mallards, can potentially be long-distance vectors of highly pathogenic avian influenza virus (H5N1) and that others, particularly tufted ducks, are more likely to act as sentinels.

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Related in: MedlinePlus

Mean pharyngeal excretion of highly pathogenic avian influenza virus (H5N1) of wild ducks by A) virus isolation and C) reverse transcription–PCR (RT-PCR). Pochard (red, closed circle), tufted duck (orange, open circle), mallard (dark blue, closed triangle), teal (light blue, open triangle), wigeon (dark green, closed square), gadwall (light green, open square); TCID50, median tissue culture infectious dose; Ct, cycle threshold. Area under the curve in the first 4 days postinoculation (mean ± 95% confidence interval) for B) virus isolation and D) RT-PCR. TU, tufted duck; PO, pochard; MA, mallard; TE, teal; WI, wigeon; GA, gadwall; red triangles, birds with severe clinical signs; black triangles, birds with mild or no clinical signs. E) Influenza virus antigen expression in epithelial cells in bronchus, parabronchus, atrium, and air capillaries of a tufted duck. F) Bronchointerstitial pneumonia, characterized by flooding of parabronchi (PB), atria (AT), and air capillaries (AC) with proteinaceous fluid and inflammatory cells in a tufted duck. G) Influenza virus antigen expression in epithelial cells lining the air sac wall and H) epithelial necrosis and lymphocytic infiltration in a gadwall. E–H original magnification ×100. Tissues were stained either by immunohistochemistry that used a monoclonal antibody against the nucleoprotein of influenza A virus as a primary antibody (E, G) or with hematoxylin and eosin (F, H).
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Figure 2: Mean pharyngeal excretion of highly pathogenic avian influenza virus (H5N1) of wild ducks by A) virus isolation and C) reverse transcription–PCR (RT-PCR). Pochard (red, closed circle), tufted duck (orange, open circle), mallard (dark blue, closed triangle), teal (light blue, open triangle), wigeon (dark green, closed square), gadwall (light green, open square); TCID50, median tissue culture infectious dose; Ct, cycle threshold. Area under the curve in the first 4 days postinoculation (mean ± 95% confidence interval) for B) virus isolation and D) RT-PCR. TU, tufted duck; PO, pochard; MA, mallard; TE, teal; WI, wigeon; GA, gadwall; red triangles, birds with severe clinical signs; black triangles, birds with mild or no clinical signs. E) Influenza virus antigen expression in epithelial cells in bronchus, parabronchus, atrium, and air capillaries of a tufted duck. F) Bronchointerstitial pneumonia, characterized by flooding of parabronchi (PB), atria (AT), and air capillaries (AC) with proteinaceous fluid and inflammatory cells in a tufted duck. G) Influenza virus antigen expression in epithelial cells lining the air sac wall and H) epithelial necrosis and lymphocytic infiltration in a gadwall. E–H original magnification ×100. Tissues were stained either by immunohistochemistry that used a monoclonal antibody against the nucleoprotein of influenza A virus as a primary antibody (E, G) or with hematoxylin and eosin (F, H).

Mentions: Pharyngeal excretion of HPAIV (H5N1) varied significantly among the 6 duck species (1-way analysis of variance of area under pharyngeal excretion curve up to 4 dpi, p<0.001), by virus isolation (Figure 2, panel A) and by RT-PCR (Figure 2, panel C). The ducks could be divided into a high-excretion group consisting of tufted ducks, pochards, and mallards, and a low-excretion group consisting of teals, wigeons, and gadwalls (Figure 2, panels B and D). Pharyngeal excretion also varied substantially among individuals within species (Appendix Figures 6 and 3, respectively.). This finding was most extreme in tufted ducks and pochards, the species in which the individuals with the highest excretion level were also those showing severe clinical signs (Figure 2, panels B and D).


Wild ducks as long-distance vectors of highly pathogenic avian influenza virus (H5N1).

Keawcharoen J, van Riel D, van Amerongen G, Bestebroer T, Beyer WE, van Lavieren R, Osterhaus AD, Fouchier RA, Kuiken T - Emerging Infect. Dis. (2008)

Mean pharyngeal excretion of highly pathogenic avian influenza virus (H5N1) of wild ducks by A) virus isolation and C) reverse transcription–PCR (RT-PCR). Pochard (red, closed circle), tufted duck (orange, open circle), mallard (dark blue, closed triangle), teal (light blue, open triangle), wigeon (dark green, closed square), gadwall (light green, open square); TCID50, median tissue culture infectious dose; Ct, cycle threshold. Area under the curve in the first 4 days postinoculation (mean ± 95% confidence interval) for B) virus isolation and D) RT-PCR. TU, tufted duck; PO, pochard; MA, mallard; TE, teal; WI, wigeon; GA, gadwall; red triangles, birds with severe clinical signs; black triangles, birds with mild or no clinical signs. E) Influenza virus antigen expression in epithelial cells in bronchus, parabronchus, atrium, and air capillaries of a tufted duck. F) Bronchointerstitial pneumonia, characterized by flooding of parabronchi (PB), atria (AT), and air capillaries (AC) with proteinaceous fluid and inflammatory cells in a tufted duck. G) Influenza virus antigen expression in epithelial cells lining the air sac wall and H) epithelial necrosis and lymphocytic infiltration in a gadwall. E–H original magnification ×100. Tissues were stained either by immunohistochemistry that used a monoclonal antibody against the nucleoprotein of influenza A virus as a primary antibody (E, G) or with hematoxylin and eosin (F, H).
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Related In: Results  -  Collection

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Figure 2: Mean pharyngeal excretion of highly pathogenic avian influenza virus (H5N1) of wild ducks by A) virus isolation and C) reverse transcription–PCR (RT-PCR). Pochard (red, closed circle), tufted duck (orange, open circle), mallard (dark blue, closed triangle), teal (light blue, open triangle), wigeon (dark green, closed square), gadwall (light green, open square); TCID50, median tissue culture infectious dose; Ct, cycle threshold. Area under the curve in the first 4 days postinoculation (mean ± 95% confidence interval) for B) virus isolation and D) RT-PCR. TU, tufted duck; PO, pochard; MA, mallard; TE, teal; WI, wigeon; GA, gadwall; red triangles, birds with severe clinical signs; black triangles, birds with mild or no clinical signs. E) Influenza virus antigen expression in epithelial cells in bronchus, parabronchus, atrium, and air capillaries of a tufted duck. F) Bronchointerstitial pneumonia, characterized by flooding of parabronchi (PB), atria (AT), and air capillaries (AC) with proteinaceous fluid and inflammatory cells in a tufted duck. G) Influenza virus antigen expression in epithelial cells lining the air sac wall and H) epithelial necrosis and lymphocytic infiltration in a gadwall. E–H original magnification ×100. Tissues were stained either by immunohistochemistry that used a monoclonal antibody against the nucleoprotein of influenza A virus as a primary antibody (E, G) or with hematoxylin and eosin (F, H).
Mentions: Pharyngeal excretion of HPAIV (H5N1) varied significantly among the 6 duck species (1-way analysis of variance of area under pharyngeal excretion curve up to 4 dpi, p<0.001), by virus isolation (Figure 2, panel A) and by RT-PCR (Figure 2, panel C). The ducks could be divided into a high-excretion group consisting of tufted ducks, pochards, and mallards, and a low-excretion group consisting of teals, wigeons, and gadwalls (Figure 2, panels B and D). Pharyngeal excretion also varied substantially among individuals within species (Appendix Figures 6 and 3, respectively.). This finding was most extreme in tufted ducks and pochards, the species in which the individuals with the highest excretion level were also those showing severe clinical signs (Figure 2, panels B and D).

Bottom Line: Wild birds have been implicated in the expansion of highly pathogenic avian influenza virus (H5N1) outbreaks across Asia, the Middle East, Europe, and Africa (in addition to traditional transmission by infected poultry, contaminated equipment, and people).By experimentally infecting wild ducks, we found that tufted ducks, Eurasian pochards, and mallards excreted significantly more virus than common teals, Eurasian wigeons, and gadwalls; yet only tufted ducks and, to a lesser degree, pochards became ill or died.These findings suggest that some wild duck species, particularly mallards, can potentially be long-distance vectors of highly pathogenic avian influenza virus (H5N1) and that others, particularly tufted ducks, are more likely to act as sentinels.

View Article: PubMed Central - PubMed

Affiliation: Erasmus Medical Center, Rotterdam, the Netherlands.

ABSTRACT
Wild birds have been implicated in the expansion of highly pathogenic avian influenza virus (H5N1) outbreaks across Asia, the Middle East, Europe, and Africa (in addition to traditional transmission by infected poultry, contaminated equipment, and people). Such a role would require wild birds to excrete virus in the absence of debilitating disease. By experimentally infecting wild ducks, we found that tufted ducks, Eurasian pochards, and mallards excreted significantly more virus than common teals, Eurasian wigeons, and gadwalls; yet only tufted ducks and, to a lesser degree, pochards became ill or died. These findings suggest that some wild duck species, particularly mallards, can potentially be long-distance vectors of highly pathogenic avian influenza virus (H5N1) and that others, particularly tufted ducks, are more likely to act as sentinels.

Show MeSH
Related in: MedlinePlus