How do scientists study avian influenza in wild birds?

To learn more about the impacts of avian influenza on wild birds and the role wild birds may play in the spread of the virus, experts from government agencies have gathered samples from hundreds of thousands of live-captured, apparently healthy wild birds; hunter-harvested birds; and dead wild birds of all species.

Testing methods include analyses of fecal samples and swabs of the bird’s trachea, oropharynx, or cloaca. Tissues can be collected from dead birds.

The majority of the live bird and hunter-harvested avian influenza surveillance programs in the U.S. were discontinued in 2010. The USGS National Wildlife Health Center is focusing on testing sick and dead migratory birds, particularly ducks, geese and swans. This will facilitate early detection, situational awareness, and appropriate response to these viruses.

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Date published: July 18, 2017

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Date published: May 1, 2017

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Date published: April 5, 2016

Alaska Still a Likely Portal for Avian Influenza

ANCHORAGE, Alaska — The U.S. Geological Survey released additional evidence that western Alaska remains a hot spot for avian influenza to enter North America. 

Date published: January 23, 2015

USGS Statement Regarding Avian Flu Found in Washington State Green-Winged Teal

Some media are reporting that the Asian H5N1 strain of highly pathogenic avian influenza has now entered the United States. This is incorrect.

Date published: March 19, 2014

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The North Atlantic region is a newly discovered important pathway for avian influenza to move between Europe and North America, according to a U.S. Geological Survey report published today.

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Female scientist looking through microscope.
2017 (approx.)

Biological science aid, Marlee Malmborg, examines and records the viability of pallid sturgeon eggs at the Columbia Environmental Research Center.

Avian Influenza: A Wild and Domestic Disease
February 2, 2017

Potential spread of highly pathogenic H5N1 strains by wild migratory ducks. H5N1 strains isolated from outbreaks in South Korea, Russia, and Japan from April to May 2008 were closely related to each other and to strains isolated from Dongting Lake in March 2008 from domestic chickens, ducks, and water. (Cappelle et al. 2014, EcoHealth).

Avian influenza viruses. Digitallycolorized negative-stained transmission electron micrograph (TEM).
August 24, 2016

Digitally-colorized negative-stained transmission electron micrograph of avian influenza viruses. Credit CDC/F.A. Murphy

2016 (approx.)

The Avian Influenza Transmission Risk Model web application depicts the intricate connections between 16 layers of administrative, environmental, and economic data in an application that runs inside a web browser. To view and manipulate the full web application, please visit The full web application requires a web browser with a large amount of memory available. This video gives an overview of the application and shows some of the features. 

2016 (approx.)

For more information on avian influenza, see Two currently circulating avian influenza viruses, highly pathogenic A(H5N1) and low pathogenic A(H7N9) (hereafter H5N1 and H7N9) are of particular concern due to their high case-fatality rates (approximately 60 and 30% currently), and economic impact to the livestock industry and public health system. H5N1 first emerged in domestic geese in southern China in 1996 (12), and has since infected 60 countries across Asia, Africa, and Europe killing 374 people. This video provides an overview of the outbreaks, using data from the United Nations Food and Agriculture (UNFAO) database. 

Image: USGS Avian Flu Research
March 15, 2016

A biological technician of the USGS National Wildlife Health Center tests chicken eggs inoculated with a field sample from wild birds to detect the presence of avian influenza virus.

Blue-winged teal in Texas with an inset that shows the avian influenza virus
March 29, 2013

Blue-winged teal in Texas. Inset shows avian influenza virus

Image: Scientists prepare to release Forster’s Tern chicks following sampling for avian influenza study.
January 1, 2010

Scientists prepare to release Forster's Tern chicks following sampling for avian influenza study.

Image: USGS Avian Flu Research
February 29, 2008

USGS scientist Dede Goldberg swabs a pintail duck for avian influenza at Monte Vista National Wildlife Refuge in Colorado.

Avian Influenza Sampling

Oral-pharyngeal sample being taken on an American black duck (cloacal samples are also taken from each bird)