Highly Pathogenic Avian Influenza (H5N1) Virus in Feathers

H5N1 highly pathogenic avian influenza (HPAI) virus causes high mortality of infected birds, with infection in multiple organs, including in feathers. Feathers have been proposed as samples for diagnosis of HPAI infection in birds, and this study is part of a broader investigation validating the use of feathers for diagnostic purposes. To understand and characterize the morphological basis for feather infection, sections from 7 different skin tracts of ducks and chickens infected with 3 different clades of H5N1 HPAI virus from Indonesia and Vietnam were examined histologically. Results showed that in ducks, lesions and viral antigen were mainly detected in the epidermis of feathers and follicles, whereas in chickens, they were mostly found in the dermis of these structures. Abundant viral antigen was found in nearly all the feathers examined from chickens, and there was no apparent difference between virus isolates or skin tracts in the proportion of feathers that were antigen positive. By immunohistochemistry, the majority of feathers from most skin tracts from ducks infected with a Vietnamese H5N1 HPAI virus contained abundant levels of viral antigen, while few feathers were antigen positive from ducks infected with 2 Indonesian viruses. These results support and inform the use of feathers for diagnostic detection of H5N1 HPAI virus in birds.

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Transatlantic spread of highly pathogenic avian influenza H5N1 by wild birds from Europe to North America in 2021

10.1101/2022.01.13.476155 ◽

2022 ◽

Author(s):

Valentina Caliendo ◽

Nicola S Lewis ◽

Anne Pohlmann ◽

Jonas Waldenstrom ◽

Marielle van Toor ◽

...

Keyword(s):

North America ◽

Avian Influenza ◽

Newfoundland And Labrador ◽

Wild Bird ◽

Bird Migration ◽

Highly Pathogenic Avian Influenza ◽

Highly Pathogenic ◽

Pathogenic Avian Influenza ◽

Influenza H5n1 ◽

H5n1 Hpai

Highly pathogenic avian influenza (HPAI) viruses of the A/Goose/Guangdong/1/1996 lineage (GsGd), which threaten the health of poultry, wildlife and humans, are spreading across Asia, Europe and Africa, but are currently absent from Oceania and the Americas. In December 2021, H5N1 HPAI viruses were detected in poultry and a free-living gull in St. John, Newfoundland and Labrador, Canada. Phylogenetic analysis showed that these viruses were most closely related to HPAI GsGd viruses circulating in northwestern Europe in spring 2021. Analysis of wild bird migration suggested that these viruses may have been carried across the Atlantic via Iceland, Greenland/Arctic or pelagic routes. The here documented incursion of HPAI GsGd viruses into North America raises concern for further virus spread across the Americas by wild bird migration.

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Avian Influenza (H5N1) Viruses Isolated from Humans in Asia in 2004 Exhibit Increased Virulence in Mammals

Journal of Virology ◽

10.1128/jvi.79.18.11788-11800.2005 ◽

2005 ◽

Vol 79 (18) ◽

pp. 11788-11800 ◽

Cited By ~ 358

Author(s):

Taronna R. Maines ◽

Xui Hua Lu ◽

Steven M. Erb ◽

Lindsay Edwards ◽

Jeannette Guarner ◽

...

Keyword(s):

Avian Influenza ◽

Highly Pathogenic Avian Influenza ◽

Highly Pathogenic ◽

Rapid Disease Progression ◽

Pathogenic Avian Influenza ◽

Multiple Organs ◽

Avian Influenza H5n1 ◽

The Brain ◽

Highly Virulent ◽

Influenza H5n1

ABSTRACT The spread of highly pathogenic avian influenza H5N1 viruses across Asia in 2003 and 2004 devastated domestic poultry populations and resulted in the largest and most lethal H5N1 virus outbreak in humans to date. To better understand the potential of H5N1 viruses isolated during this epizootic event to cause disease in mammals, we used the mouse and ferret models to evaluate the relative virulence of selected 2003 and 2004 H5N1 viruses representing multiple genetic and geographical groups and compared them to earlier H5N1 strains isolated from humans. Four of five human isolates tested were highly lethal for both mice and ferrets and exhibited a substantially greater level of virulence in ferrets than other H5N1 viruses isolated from humans since 1997. One human isolate and all four avian isolates tested were found to be of low virulence in either animal. The highly virulent viruses replicated to high titers in the mouse and ferret respiratory tracts and spread to multiple organs, including the brain. Rapid disease progression and high lethality rates in ferrets distinguished the highly virulent 2004 H5N1 viruses from the 1997 H5N1 viruses. A pair of viruses isolated from the same patient differed by eight amino acids, including a Lys/Glu disparity at 627 of PB2, previously identified as an H5N1 virulence factor in mice. The virus possessing Glu at 627 of PB2 exhibited only a modest decrease in virulence in mice and was highly virulent in ferrets, indicating that for this virus pair, the K627E PB2 difference did not have a prevailing effect on virulence in mice or ferrets. Our results demonstrate the general equivalence of mouse and ferret models for assessment of the virulence of 2003 and 2004 H5N1 viruses. However, the apparent enhancement of virulence of these viruses in humans in 2004 was better reflected in the ferret.

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