What is the difference between low pathogenic and highly pathogenic avian influenza?

The designation of low or highly pathogenic avian influenza refers to the potential for these viruses to kill chickens. The designation of “low pathogenic” or “highly pathogenic” does not refer to how infectious the viruses may be to humans, other mammals, or other species of birds.

Most strains of avian influenza are not highly pathogenic and cause few signs of disease in infected wild birds. However, in poultry, some low-pathogenic strains can mutate into highly pathogenic avian influenza strains that cause a contagious and severe illness among poultry and sometimes wild birds, and often death.The effect is dependent on the viral strain and host species.

Learn more at the USGS Avian Influenza website.

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Are birds the only species that is susceptible to West Nile Virus infection?

West Nile Virus (WNV) has been detected in at least 48 species of mosquitoes, over 320 species of birds, at least 2 species of reptiles, and more than 25 mammalian species, including horses and humans. Birds are the natural host and reservoir of WNV. Although other animals are susceptible to WNV infection, only birds develop a high enough virus...

Can people get avian influenza?

While rare, human infections with avian influenza viruses have occurred. The Centers for Disease Control and Prevention considers the risk to the general public from HPAI H5 infections in wild birds, backyard flocks, and commercial poultry, to be low. To date, no humans or other mammals have shown signs of disease from the HPAI viruses found in...

Can wild birds spread avian influenza to domestic poultry?

Although it is possible for domestic poultry to become infected with avian influenza from direct contact with wild birds, it is more likely that avian influenza viruses are spread indirectly to poultry on contaminated feed, clothing, and equipment. Agricultural agencies encourage producers to prevent wild birds and other wildlife from coming into...

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...

What is the meaning of the numbers next to the “H” and “N” in avian influenza designations?

Avian influenza (AI) viruses are classified by a combination of two groups of proteins: hemagglutinin or “H” proteins, of which there are 16 (H1 to H16), and neuraminidase or “N” proteins, of which there are nine (N1 to N9). Many different combinations of “H” and “N” proteins are possible. Each combination is considered a different subtype and can...

What are the different types of avian influenza?

Avian Influenza (AI) type A viruses are divided into subtypes based on two proteins on the surface of the virus: Hemagglutinin (HA), of which there are 16 subtypes (H1-H16) Neuraminidase (NA), of which there are 9 subtypes (N1-N9) Many combinations of HA and NA proteins are possible (i.e., H5N1, H5N2, H7N2, H7N8, etc). AI viruses are also...

What is Avian Influenza?

Avian influenza (AI) is caused by an influenza type A virus that can infect poultry such as chickens, turkeys, pheasants, quail, domestic ducks, geese, and guinea fowl. It is carried by wild waterfowl (ducks and geese) and shorebirds. Learn more at the USGS Avian Influenza website .

What is chronic wasting disease?

Chronic wasting disease (CWD) is a fatal, neurological illness occurring in North American cervids (members of the deer family), including white-tailed deer, mule deer, elk, and moose. Since its discovery in 1967, CWD has spread geographically and increased in prevalence locally. CWD is contagious; it can be transmitted freely within and among...

What is White-nose Syndrome?

White-nose syndrome is an emergent disease of hibernating bats that has spread from the northeastern to the central United States at an alarming rate. Since the winter of 2007-2008, millions of insect-eating bats in at least 33 states and seven Canadian provinces have died from this devastating disease. The disease is named for the white fungus,...
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Date published: December 4, 2017

Avian Flu From Abroad Can Spread in North American Poultry, Wild Birds

Some avian influenza, or bird flu, viruses that are able to enter North America from other continents through migrating birds can be deadly to poultry and can infect waterfowl populations, according to a recently published U.S. Geological Survey study.

Date published: July 18, 2017

Unusual Suspects: Diving Ducks and Avian influenza

Due to the global threat to health and human safety posed by avian influenza monitoring has been conducted in the United States to determine the prevalence of such viruses in our wild waterfowl.

Date published: May 1, 2017

Avian Flu Testing of Wild Ducks Informs Biosecurity and Can Reduce Economic Loss

Ducks in North America can be carriers of avian influenza viruses similar to those found in a 2016 outbreak in Indiana that led to the losses of hundreds of thousands of chickens and turkeys, according to a recent study.

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: September 3, 2014

Avian Flu in Seals Could Infect People

The avian flu virus that caused widespread harbor seal deaths in 2011 can easily spread to and infect other mammals and potentially humans.

Date published: March 19, 2014

North Atlantic May Be a New Route for Spread of Avian Flu to North America

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.

Date published: November 12, 2004

Avian Cholera Could Spread from Great Salt Lake

Scientists at the U.S. Geological Survey’s (USGS) National Wildlife Health Center are concerned that avian cholera, which recently killed about 30,000 eared grebes—small, diving water birds—at Great Salt Lake, Utah, could spread as birds migrate south for the winter, the agency announced today.

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Avian influenza sample
July 26, 2017

Collecting a sample to test for Avian Influenza

Avian influenza among wild waterfowl is a concern among resource managers and owners of domestic fowl. The scientists take a sample to process at the lab.

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

Avian Influenza: A Wild and Domestic Disease

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).

Multiple Petri dishes with various water samples monitoring showing color differences for antibiotic resistance.
December 12, 2016

Antibiotic Resistance Petri dishes

Multiple Petri dishes with various water samples monitoring for antibiotic resistance.

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

Avian influenza virus

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

August 3, 2016

Visual History of Worldwide Avian Influenza Outbreaks

For more information on avian influenza, see http://www.pwrc.usgs.gov/ai. 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

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August 3, 2016

Avian Influenza Transmission Risk Model Web Application Virtual Tour

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 http://www.pwrc.usgs.gov/ai. The full web application

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Image: USGS Avian Flu Research
March 15, 2016

USGS Avian Flu Research

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

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

Releasing Forster’s Tern Chicks after Sampling for Avian Flu

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

USGS
June 3, 2008

You, Too, Can Track Avian Flu and Other Wildlife Diseases

Want to stay on top of wildlife disease developments throughout the world? USGS scientists Josh Dein and Hon Ip, and USGS web content manager Cris Marsh tell us how with some great Web tracking tools.