10 research outputs found

    Novel Reassortant H5N6 Influenza A Virus from the Lao People's Democratic Republic Is Highly Pathogenic in Chickens.

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    Avian influenza viruses of H5 subtype can cause highly pathogenic disease in poultry. In March 2014, a new reassortant H5N6 subtype highly pathogenic avian influenza virus emerged in Lao People's Democratic Republic. We have assessed the pathogenicity, pathobiology and immunological responses associated with this virus in chickens. Infection caused moderate to advanced disease in 6 of 6 chickens within 48 h of mucosal inoculation. High virus titers were observed in blood and tissues (kidney, spleen, liver, duodenum, heart, brain and lung) taken at euthanasia. Viral antigen was detected in endothelium, neurons, myocardium, lymphoid tissues and other cell types. Pro-inflammatory cytokines were elevated compared to non-infected birds. Our study confirmed that this new H5N6 reassortant is highly pathogenic, causing disease in chickens similar to that of Asian H5N1 viruses, and demonstrated the ability of such clade 2.3.4-origin H5 viruses to reassort with non-N1 subtype viruses while maintaining a fit and infectious phenotype. Recent detection of influenza H5N6 poultry infections in Lao PDR, China and Viet Nam, as well as six fatal human infections in China, demonstrate that these emergent highly pathogenic H5N6 viruses may be widely established in several countries and represent an emerging threat to poultry and human populations

    Tropism of influenza H5N6 virus in experimentally infected chickens.

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    <p>Immunohistochemistry for influenza A nucleoprotein antigen (brown staining) in representative tissues infected with H5N6 virus. (A) Brain, chicken 1. Viral antigen can be seen in neurons (corners of image) and capillary endothelium (arrows). (B) Heart, chicken 4. Viral antigen is predominantly within cardiomyocytes with some antigen present in capillary endothelium (arrow). (C) Liver, chicken 4. Most of the viral antigen in liver is within sinusoidal endothelium. (D) Lung, chicken 5. Viral antigen is abundant in the respiratory parenchyma of lung and also found in the endothelium of large blood vessels (arrow). (E) Spleen, chicken 6. Viral antigen is found in histiocytic cells, but not lymphocytes. (F) Skin, with feather root and follicle, chicken 5. Viral antigen is present in feather pulp and in capillaries of the dermis (arrow). All scale bars are 100 μm.</p
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