Order Code RL33795
Avian Influenza in Poultry and Wild Birds
January 12, 2007
Jim Monke
Analyst in Agricultural Policy
Resources, Science and Industry Division
M. Lynne Corn
Specialist in Natural Resources
Resources, Science, and Industry Division

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Avian Influenza in Poultry and Wild Birds
Summary
Avian influenza is a viral disease that primarily infects birds, both domestic and
wild. Certain strains of bird flu break the avian barrier and have been known to
infect other animals and humans. Avian flu viruses are common among wild bird
populations, which act as a reservoir for the disease. While rarely fatal in wild birds,
avian flu is highly contagious and often fatal in domestic poultry, prompting strict
biosecurity measures on farms. International trade restrictions imposed by countries
to counter avian flu can have large economic effects.
A strain of highly pathogenic avian influenza (H5N1) has spread throughout
Asia since 2003, infecting mostly poultry, some wild birds, and a limited number of
humans through close domestic poultry-to-human contact. The virus has also spread
beyond Asia, reaching Europe in 2005 and the Middle East and Africa in early 2006.
Over 250 million poultry have died or been destroyed internationally. The human
mortality rate among the more than 250 people infected exceeds 50%. Fears that the
virus could mutate to allow efficient human-to-human transmission and cause a
human pandemic have prompted a massive political and public health response.
Since wild birds can carry the highly pathogenic H5N1 virus, federal, state, and
other agencies have increased surveillance of wild and migratory birds. Surveillance
is particularly high in Alaska, where Asian and American flyways overlap. Migrating
birds from Asia could carry the virus to Alaska and infect birds from the Americas
on shared nesting grounds. The newly infected birds could carry the virus down
North American flyways. The United States also has blocked imports of poultry and
poultry products from H5N1-infected countries. Nonetheless, imports into Central
and South America could introduce the virus to the Western Hemisphere, and
subsequent wild bird migration could bring the virus north into the United States.
The highly pathogenic H5N1 strain has not yet been detected in the United
States. But surveillance has detected different, low pathogenicity strains in wild bird
populations, including a low pathogenicity H5N1. The low pathogenicity strain does
not pose the same threat as highly pathogenic H5N1. Even if highly pathogenic
H5N1 is found in the Americas, it does not signal the onset of a global human
pandemic. The virus apparently has not yet mutated to allow human-to-human
transmission, and scientists disagree whether or when this may happen.
Controlling avian flu in poultry, and to the extent possible in wild birds, is seen
as the best way to prevent a human pandemic from developing — by reducing the
number of animal hosts in which the virus may evolve. Indemnity payments to
compensate farmers for birds destroyed in eradication efforts are seen as an important
element of increasing success in control efforts.
Congressional agriculture committees have held hearings on avian influenza
preparedness, and appropriators have increased funding for surveillance and other
preparedness activities for poultry and wild birds.
This report will be updated periodically.

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Contents
What is Avian Influenza? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Status of Avian Influenza Outbreaks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Status In the United States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Status In the Rest of the World . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Transmission . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Transmission In Wild Birds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Transmission In Poultry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Transmission Across International Borders . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Human Infection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Food Safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
International Control Efforts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Preventing Infection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Vaccines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Eradicating Outbreaks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Compensation for Farmers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Economic Impacts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Legislative Actions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Congressional Hearings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Federal Appropriations to Control Avian Flu . . . . . . . . . . . . . . . . . . . . . . . 14
Poultry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Wild Birds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
List of Figures
Figure 1. Migratory bird flyways of the world . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Figure 2. Samples collected: surveillance of wild birds for avian influenza,
Apr. 1-Dec. 8, 2006 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Figure 3. Test results: locations of presumptive positive H5N1 in wild birds;
all confirmed not H5N1 or low pathogenicity H5N1 . . . . . . . . . . . . . . . . . . . 4
Figure 4. Geographic concentration of broiler production . . . . . . . . . . . . . . . . . . 13

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Avian Influenza in Poultry and Wild Birds
What Is Avian Influenza?
Avian influenza (AI) viruses exist throughout the world in many different
strains. Avian flu is an Influenza A virus that infects both wild and domestic birds,
and certain strains have been known to infect both animals and humans. This report
discusses avian flu broadly as it affects agriculture and wild birds, especially with
reference to highly pathogenic H5N1 avian flu.
Avian flu assumes two forms in birds:
! a low pathogenicity (LPAI) form that causes mild illness, and
! a highly pathogenic (HPAI) form that is extremely contagious,
causes severe illness, and frequently has high rates of mortality.
Pathogenicity is determined using two methods: genetic sequencing, and
inoculating healthy chicks and monitoring their mortality. Mortality under highly
pathogenic avian flu ranges from 30%-100%, and is usually less than 20% for low
pathogenicity.
Both forms are possible in many strains, designated by the letters H and N. The
strain designations refer to surface proteins on the virus called hemagglutinin (H) and
neuraminidase (N). Each AI virus has one hemagglutinin and one neuraminidase
protein. Sixteen H subtypes and nine N subtypes have been identified, and are
designated by numbers. They can occur in any combination, resulting in 144 possible
strains (for example, H1N1, H7N2, etc.).
Most strains are low pathogenicity, but some strains (particularly H5 and H7)
can mutate from LPAI into HPAI during the course of an outbreak. Globally during
the past 20 years, H5 or H7 LPAI viruses have mutated into HPAI on five occasions.
Thus, low pathogenicity outbreaks in domestic poultry are treated aggressively.
Low pathogenicity outbreaks in poultry are not uncommon, since LPAI is
entrenched in wild birds. The most recent cases in U.S. poultry occurred in 2004,
with low pathogenicity strains of H7N2 in Delaware, Maryland, and New Jersey; and
low pathogenicity H2N2 in Pennsylvania. Separately, an H5N2 strain was found in
Texas in 2004 and was classified genetically as highly pathogenic, although it did not
manifest as such in terms of mortality. Other recent cases include low pathogenicity
outbreaks of H7N2 in the Northeast in 2003, and in the mid-Atlantic in 2002. Only
three highly pathogenic outbreaks have occurred in the United States in the past
century (1924, 1983, and 2004).

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Status of Avian Influenza Outbreaks
A strain of highly pathogenic avian influenza (H5N1) has spread throughout
Asia since 2003, and has subsequently moved into Europe, the Middle East, and
Africa. It has infected mostly poultry and wild birds, but a limited number of humans
have contracted the disease through close domestic poultry-to-human contact. Over
250 million poultry have died or been destroyed internationally.
Status in the United States1
Currently, there are no outbreaks of any avian flu virus in domestic poultry in
the United States. Moreover, the highly pathogenic H5N1 strain of current global
concern has not reached North America in wild birds, poultry, or humans.
Figure 1. Migratory Bird Flyways of the World
Source: U.S. Geological Survey, [http://alaska.usgs.gov/science/biology/avian_influenza/flyways.
html]. Shaded areas give only a general impression of migration routes: storms, high winds, and
random variations can send any bird off the routes shown here. Available in color on the CRS website
at [http://www.crs.gov].
Since wild birds can carry the highly pathogenic H5N1 virus, the U.S.
Department of Agriculture (USDA) and the Department of the Interior (DOI) have
increased surveillance of wild and migratory birds. Examining migration routes
shows how the disease could spread from Asia into North America (Figure 1).
1 See U.S. Dept. of Agriculture (USDA) at [http://www.usda.gov/birdflu], and the Centers
for Disease Control and Prevention (CDC) at [http://www.cdc.gov/flu/avian].

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Surveillance is particularly high in Alaska, where Asian and American flyways
overlap. Migrating birds from Asia could carry the virus to Alaska, and infect birds
from the Americas on shared nesting grounds. The newly infected birds could carry
the virus down North American flyways. This was particularly a concern through the
summer and fall of 2006, but the possibility may return later in 2007, since highly
pathogenic H5N1 continues to circulate in Asia.
Since April 2006, over 55,000 samples have been collected from wild birds.2
About 30% of those samples are from Alaska, with the remainder spread throughout
the lower 48 States (Figure 2). While no instance of highly pathogenic H5N1 has
been found to date in North America, the tests have detected other low pathogenicity
strains of avian influenza (Figure 3). For example, in August 2006, two wild mute
swans in Michigan were confirmed positive for a low pathogenicity strain of H5N1.
The swans showed no signs of sickness. This LPAI strain does not threaten poultry
or humans like highly pathogenic H5N1, is not in commercial flocks, and was
already known to exist in North America. Most recently, a northern shoveler (a type
of duck) in Missouri initially tested positive for H5N1 on November 4, 2006.
Subsequent testing indicates a low pathogenicity strain of H1N1.
Preliminary testing of birds can show positive results for H5N1 for three
different reasons. First, if a bird is infected with two different strains of avian
influenza, one with H5, and another with N1, the test may be positive. Birds initially
testing positive for the presence of both proteins require further testing to determine
if the H5N1 viral type itself is present. Second, some forms of H5N1 are low
pathogenicity and are already somewhat common in North American wild bird
populations. The low pathogenicity H5N1 strain (sometimes called “North
American” H5N1) is not a human health problem like the highly pathogenic Asian
strain of H5N1. Hunters who might eat infected birds, and hunting dogs that might
retrieve them, are at no known risk from low pathogenicity H5N1. All the H5N1
virus found to date in the United States and Canada has been LPAI. The third
possibility — an H5N1 that is also highly pathogenic (the strain of concern in the
worldwide outbreak) — has not yet been reported in the Americas.
Status in the Rest of the World3
The first official report of H5N1 in humans was a 1997 outbreak in Hong Kong,
with transmission from domestic poultry to humans. This outbreak was contained
by an aggressive program to slaughter exposed poultry (“stamping out”). But the
virus re-emerged several years later.
2 A description of the overall surveillance plan and data are available from the National
Biological Information Infrastructure, “Highly Pathogenic Avian Influenza Early Detection
Data System (HEDDS),” at [http://wildlifedisease.nbii.gov/ai/index.jsp]. USDA’s Office
of Inspector General identified gaps in the response and surveillance plan. USDA-OIG,
Animal and Plant Health Inspection Service Oversight of Avian Influenza, Audit Report
33099-11-Hy (June 2006), at [http://www.usda.gov/oig/webdocs/33099-11-HY.pdf]. Steps
have been taken subsequently to improve surveillance.
3 For discussion of international issues and avian influenza, see the World Health
Organization (WHO) at [http://www.who.int/en], U.N. Food and Agriculture Organization
(FAO) at [http://www.fao.org], and the World Organization for Animal Health (OIE) at
[http://www.oie.int].

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Figure 2. Samples Collected: Surveillance of Wild Birds for
Avian Influenza, April 1-December 8, 2006
Source: U.S. Dept. of Agriculture and U.S. Dept. of the Interior, [http://wildlifedisease.nbii.gov/ai].
Figure 3. Test Results: Locations of Presumptive Positive H5N1 in
Wild Birds (all confirmed either low pathogenicity H5N1 or not H5N1)
Source: Adapted by CRS (Nov. 2006), based on U.S. Dept. of Agriculture and U.S. Dept. of the
Interior, [http://wildlifedisease.nbii.gov/ai/lpai-table.jsp].

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Since December 2003, at least 10 Asian countries have had confirmed outbreaks
of highly pathogenic H5N1 in poultry. The first generally recognized outbreak of the
H5N1 strain in wild birds occurred among waterfowl at the Qinghai Lake Nature
Reserve in west-central China in 2005. In 2005, the virus spread westward toward
eastern Europe, being confirmed in six new countries. In 2006, it spread to dozens
of new countries in Europe, the Middle East, and Africa. The virus has appeared in
55 countries on every continent of the eastern hemisphere, except Australia.4
The H5N1 outbreak in poultry and birds has grown in scale, causing massive
international government responses, and economic, food, and trade impacts due to
the animal disease and public health concerns. The U.N. Food and Agriculture
Organization (FAO) estimates that over 250 million poultry have died or been culled
internationally. Some countries were reluctant to acknowledge the disease for fear
of economic consequences. In other countries, the lack of compensation for farmers
whose flocks are destroyed has been a disincentive to report outbreaks early.
Transmission
Transmission In Wild Birds
Wild birds are the primary natural reservoir for Influenza A viruses.
Transmission of the disease among wild birds is through fecal material and appears
most commonly among waterfowl (ducks, geese, and their relatives), shorebirds
(plovers, sandpipers, and their relatives), gulls, and terns. In wild populations, avian
flu is not typically fatal — or even apparent. However, an outbreak of the H5N1
strain is known to have appeared in Qinghai province in China in May 2005. Most
of the wild species at greatest risk are highly migratory, e.g., ranging from Siberia to
southern Asia, or Norway to central Africa. Many nest in dense aggregations during
the breeding season (e.g., many species of terns and gulls), or winter in dense flocks
(e.g., many species of gulls, geese, and ducks), or form huge flocks for migration or
at migratory stop-over sites (e.g., many species of plovers, sandpipers, and their
relatives). Crowded conditions such as these tend to facilitate transmission of a
disease.
While avian influenza is not typically fatal in wild birds, some scientists fear
that an outbreak of HPAI could be particularly harmful to populations of birds
already under threat from habitat loss or excessive harvests.
4 World Organization for Animal Health (OIE), “Update on Avian Influenza in Animals,”
Dec. 7, 2006, at [http://www.oie.int/downld/avian%20influenza/a_ai-asia.htm]. Countries
reporting highly pathogenic H5N1 in wild birds or poultry at some time since 2003 include
Afghanistan, Albania, Austria, Azerbaijan, Bosnia and Herzegovina, Bulgaria, Burkina
Faso, Cambodia, Cameroon, China, Côte d’Ivoire, Croatia, Czech Republic, Denmark,
Djibouti, Egypt, France, Georgia, Germany, Greece, Hong Kong, Hungary, Kazakhstan,
India, Indonesia, Iraq, Iran, Israel, Italy, Japan, Jordan, Laos, Malaysia, Mongolia, Myanmar,
Niger, Nigeria, Palestine, Pakistan, Poland, Republic of Korea, Romania, Russia, Serbia and
Montenegro, Slovakia, Slovenia, Spain, Sudan, Sweden, Switzerland, Thailand, Turkey,
Ukraine, United Kingdom, and Vietnam.

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Transmission In Poultry
Domesticated poultry flocks can be infected by contact with wild birds and their
excretions. Avian flu is highly contagious in poultry, and more so in crowded
conditions. The virus is spread by contact with infected feces, nasal, or eye
excretions. The incubation period for avian flu may last as long as 10 days, and the
virus may be shed from live poultry for up to 21 days. Confined poultry sheds used
in commercial production prevent contact with wild birds and thus reduce a source
of infection, but may magnify the economic impact if the virus is introduced. People,
clothing, vehicles, and supplies can carry the virus between farms. Thus, strict
biosecurity measures are adopted by nearly all U.S. commercial poultry farms, not
only to prevent the spread of avian flu, but also to shield the flocks from other
infections.5
Avian flu viruses have been common in live bird markets (also known as wet
markets). These markets sell less than 1% of U.S. poultry, but outbreaks concern
commercial growers, who practice tighter biosecurity than backyard growers or live
bird markets. USDA has focused on these markets because insufficient biosecurity
allowed birds and equipment to intermingle at the market and return to farms.
Examples of states with live bird markets include New York, New Jersey, and Texas.
In Asia, a larger network of live bird markets and backyard farms has made
eradication difficult.
Transportation of roosters for cock fighting, which is illegal in the United States
(except in Louisiana and New Mexico) and some other parts of the world, is also a
suspected route of disease transmission.
Transmission Across International Borders
Pathogens may spread across international borders in several ways:
! naturally (e.g., wild bird migration, wind),
! accidentally (e.g., in legal or smuggled shipments of animals or
products that happen to be infected), and
! intentionally (e.g., legally for controlled use in science, or illegally
for crime or terrorism).
The ability of H5N1 to spread naturally via migratory birds has been discussed
above, and such migration cannot be stopped at international political borders.
Surveillance programs are designed to detect the pathogen once it crosses a border,
and enable a more rapid response than without surveillance.
To reduce the possibility that highly pathogenic H5N1 enters the United States
accidentally or intentionally, the USDA has blocked imports of poultry and poultry
products (such as feathers, meat, or eggs) from affected countries, and increased
smuggling interdiction efforts. Highly pathogenic avian influenza viruses are
5 For biosecurity recommendations, see the USDA “Biosecurity for the Birds” website at
[http://www.aphis.usda.gov/vs/birdbiosecurity/hpai.html].

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considered a select agent under bioterrorism rules (9 C.F.R. § 121.3), and are subject
to restrictions for their possession, use, and transportation.6 The USDA Animal and
Plant Health Inspection Service (APHIS) determines the scope of import restrictions
regarding live animals and animal products, and issues import and other health
regulations. APHIS employs smuggling interdiction units and staff at pre-inspection
stations internationally to enforce import restrictions. Moreover, the domestic border
inspectors of Department of Homeland Security (DHS) Customs and Border
Protection check passengers, cargo, and conveyances (vehicles, ships, and planes) at
ports of entry for prohibited items. DHS inspectors include a cadre of agricultural
specialists, many of whom were formerly employed by APHIS prior to the transfer
of agricultural border inspectors to DHS in 2003.
Despite the attention given to migratory bird surveillance in North America,
some believe that poultry imports into Central and South America are a more likely
pathway for the virus to enter the Western Hemisphere.7 If the virus spreads from
poultry to wild birds, subsequent wild bird migration could bring the virus north into
the United States. Officials may have time to redeploy wild bird surveillance to
focus on this possible pathway.
Human Infection8
Certain avian flu strains, including H5N1, can infect humans through close
poultry-to-human contact, usually through contact with fecal matter or other live bird
excretions in backyard settings or home slaughtering. Human infection has not
appeared to result from contact with wild birds.
While the species barrier is significant, the effects have been severe when
infection does occur. H5N1 infection in humans may produce rapid deterioration
leading to viral pneumonia and organ failure. Fatality rates are high; over 50% of the
more than 250 people infected with highly pathogenic H5N1 (mostly in Asia) have
died.9 Officials worry that the virus could mutate or combine with human flu viruses
to allow efficient human-to-human transmission, which could lead to a human flu
pandemic.
If highly pathogenic H5N1 is found in the Americas, it does not signal the onset
of a global human pandemic. The virus has not yet mutated to allow human-to-
human transmission, and scientists disagree on the likelihood of this happening.
6 For more background on select agents, see CRS Report RL32521, Agroterrorism: Threats
and Preparedness, by Jim Monke.
7 A. M. Kilpatrick et al., “Predicting the Global Spread of H5N1 Avian Influenza,”
Proceedings of the National Academies of Science (Dec. 19, 2006), pp. 19368-19373.
8 For more on public health issues, see CRS Report RL33145, Pandemic Influenza:
Domestic Preparedness Efforts, by Sarah A. Lister.
9 WHO, “Confirmed Human Cases of Avian Influenza A (H5N1),” at [http://www.who.int/
csr/disease/avian_influenza/country/en].

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Food Safety. No epidemiological evidence exists indicating that people have
been infected with any avian flu virus, including H5N1, from properly cooked
poultry or eggs. The virus is killed at conventional cooking temperatures (160° F),
making properly cooked poultry safe. However, highly pathogenic viruses such as
H5N1 can spread to nearly all parts of an infected bird, survive in raw poultry, and
be spread if contaminated poultry is marketed and prepared.10 Thus, the Centers for
Disease Control and Prevention (CDC) and the USDA Food Safety and Inspection
Service recommend standard food safety practices, such as those for preventing
infection from Salmonella and E. coli.11
The vast majority of poultry and poultry products in the United States are
produced in large-scale, commercial poultry farms under strict veterinary control.
Infected poultry are very unlikely to enter the food chain, as nearly all commercial
growers participate in avian flu testing programs. When avian flu viruses are found,
any infected flocks are destroyed (not slaughtered for food) to preserve food safety
and prevent the virus from spreading beyond the infected area. Poultry products from
backyard flocks and live bird markets do not receive the same level of inspection as
commercial production, but typically are consumed on-farm or in limited distribution
circles rather than entering the traditional farm-to-fork food chain. Backyard poultry
and poultry bought at live bird markets are not a primary source of food in the United
States (less than 1% of poultry).
Control
In the United States, avian flu in poultry is controlled through prevention and
eradication by individual farmers cooperating with industry associations and state and
federal governments. APHIS is the lead federal agency. Internationally, FAO has
a joint response plan with the World Health Organization (WHO) for the current
outbreak.
International Control Efforts12
As H5N1 spreads, it may become established in countries with inadequate
veterinary services or animal husbandry practices. Chances increase that the virus
10 WHO, “Avian Influenza (AI): Food Safety Prevention Measures,” at [http://www.
euro.who.int/eprise/main/WHO/Progs/FOS/Microbiological/20041019_1], and “Highly
Pathogenic H5N1 Avian Influenza Outbreaks: Food Safety Implications,” Nov. 4, 2005, at
[http://www.who.int/foodsafety/fs_management/No_07_AI_Nov05_en.pdf].
11 USDA Fact Sheet, “Avian Influenza,” March 2006, [http://www.usda.gov/wps/portal/
usdahome?contentidonly=true&contentid=2005/11/0511.xml].
12 FAO, “Avian Influenza Control and Eradication: FAO’s Proposal for a Global
Programme,” FAO, Mar. 2006, at [http://www.fao.org/ag/againfo/subjects/documents/
ai/Global_Programme_March06.pdf]; and FAO and OIE, in cooperation with WHO, “A
Global Strategy for the Progressive Control of Highly Pathogenic Avian Influenza (HPAI),”
Nov. 2005, at [http://www.fao.org/docs/eims/upload//210745/Glo_pro_HPAI_oct05_en.
pdf]. See also CRS Report RL33219, U.S. and International Responses to the Global
Spread of Avian Flu: Issues for Congress, by Tiaji Salaam-Blyther.

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will evolve through mutation or re-assortment into a strain that could be transmitted
easily between humans. Thus, FAO and WHO developed a strategy calling for the
swift and coordinated control of avian flu in poultry as the best way to prevent or
delay a human pandemic from developing, by reducing the number of animal hosts
in which the virus may evolve.
The World Organization for Animal Health (OIE)13 revised its reporting
standards for avian flu in 2006. Previously, only highly pathogenic avian flu was a
“reportable disease,” but the new rules include low pathogenicity strains of H5 and
H7 avian influenza. Making low pathogenicity H5 and H7 reportable diseases
requires exporting countries to upgrade their surveillance and eradication protocols
to demonstrate freedom from the disease. USDA accomplished this upgrade with
new regulations issued in September 2006 (see below).
Preventing Infection
Biosecurity practices are the most important means of preventing outbreaks in
poultry. These practices include preventing contact between wild birds and poultry,
and limiting non-essential human access to farm buildings. For example, delivery
trucks and personnel are cleaned and disinfected before entering a biosecure area, or
moving between farms or barns. In other parts of the world, small farms or backyard
flocks without biosecurity practices have posed greater problems for control. Such
animal husbandry practices are slow to change.
Surveillance and detection also form an important component of prevention.
As discussed earlier in this report, federal and state agencies have increased
surveillance of wild birds for H5N1. In 2006, APHIS issued new regulations for the
control of low pathogenicity H5 and H7 avian influenza in poultry and a new
indemnity program (71 Fed. Reg. 56302, Sept. 26, 2006). These regulations (9
C.F.R. § 56, 146, and 147) are voluntary as part of the National Poultry Improvement
Plan,14 but have strong incentives for participation since eligibility for federal
indemnity payments are linked to participation in the surveillance program. The first
component is diagnostic surveillance of all live poultry under APHIS-approved state-
level programs. The second component is a state-level response and containment
plan, also needing APHIS approval. The third component is active surveillance of
13 The World Organization for Animal Health (known by its French name and acronym
Office International des Epizooties, OIE) is an international organization created in 1924
with 166 member countries. It is the world’s official information clearinghouse for animal
diseases and health. Member countries report diseases that occur on their territory, and the
OIE disseminates the information, allowing other countries to take preventive action based
on accepted scientific standards for reporting. The OIE also analyzes scientific information
on animal disease control, provides technical support, and develops normative documents
that are recognized by the World Trade Organization for international trade and sanitary
rules; see [http://www.oie.int].
14 The National Poultry Improvement Plan applies new technologies, establishes standards
for disease-free status, and allows uniformity with the goal to improve poultry health and
the quality of poultry products. Federal, state, and industry representatives cooperate in
setting goals and standards. Participation is voluntary. States administer the program in
cooperation with USDA. [http://www.aphis.usda.gov/vs/npip].

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slaughtering plants for meat-type poultry, and egg-laying flocks for breeding flocks
and table-egg layers.
Vaccines. While vaccination of poultry is possible and has been used on a
small scale with some success, it generally is not considered a sufficient control
method. Vaccination poses problems for international trade, as many countries will
not import poultry products from other countries that use vaccination, since animals
will test positive for antibodies. If vaccination is not administered and monitored
correctly, it can allow the virus to become entrenched and continue to spread or
mutate.15
In the United States, vaccination is most likely to be used for breeding poultry,
egg layers, and other higher value birds. Vaccination in a ring surrounding an
eradication zone is another possible vaccination strategy.
In September 2006, USDA’s National Veterinary Stockpile had 110 million
doses of avian influenza vaccine available for poultry. Within this total, 75 million
doses were for H5 viruses such as H5N2 and H5N9, and these vaccines have been
shown to be effective against the Asian H5N1 strain. About 35 million doses are for
H7 viruses. USDA has plans to acquire access to up to 500 million doses through
agreements with vaccine manufacturers.
Eradicating Outbreaks
Because the virus is highly contagious and easily spread in poultry, the most
common method of control in an outbreak is to establish quarantines (of birds,
contaminated products, conveyances, etc.), restrict movement, and cull the infected
flocks and certain flocks in close proximity to the infected flock (also called
“stamping out,” or depopulating). Following depopulation, buildings and equipment
are rigorously disinfected before new birds are allowed, a process that takes at least
several weeks. The virus is killed by common disinfectants or heat (about 160° F).
Carcass disposal options usually include composting, burial, incineration, or
rendering. Affected flocks that are not destroyed eventually may be marketed under
controlled conditions with strict waiting periods and additional testing so that the
infectious period has passed.
Federal statute allows the destruction of affected animals (9 C.F.R. § 53.4). The
USDA National Veterinary Services Lab conducts confirmatory tests on the
pathogenicity and type of virus. When the United States does have outbreaks, USDA
works to limit restrictions imposed by foreign countries on U.S. exports so that only
15 Nicholas Savill et al., “Silent spread of H5N1 in vaccinated poultry,” Nature, vol. 442 (17
Aug. 2006), p. 757, at [http://www.nature.com/nature/journal/v442/n7104/pdf/442757a.pdf].
Ilaria Capua and Stefano Marangon, “Vaccination for avian influenza in Asia,” Vaccine, vol.
22 (2004), at [http://www.oie.int/eng/avian_influenza/vaccination%20in%20asia.pdf], and
Ilaria Capua and Stefano Marangon, “The use of vaccination as an option for the control of
avian influenza,” Proceedings of the 71st General Session of the OIE, May 2003, at
[http://www.oie.int/eng/avian_influenza/a_71%20sg_12_cs3e.pdf].

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exports from defined geographic areas actually affected by the virus are banned.
USDA also works to lift restrictions once the outbreak is eradicated.
Domestic outbreaks usually are managed through joint federal, state, and
industry cooperation. States usually lead the response for depopulation and
quarantines of surrounding areas that are imposed until the disease is eradicated.
APHIS provides personnel and equipment to advise and supplement state resources.
As part of the National Veterinary Stockpile, USDA has assembled pallets of
personal protective equipment (PPE) and other response equipment that can be used
when state resources are inadequate. In highly pathogenic avian flu outbreaks,
APHIS may take a larger role. In 2006, APHIS published a “National Highly
Pathogenic Avian Influenza Response Plan” that outlines all aspects and expectations
for the response activities.16
Compensation for Farmers. Compensation (indemnity) programs are
desired to encourage farmers to report outbreaks and cooperate with control programs
when culling is needed. States generally manage indemnification programs for low
pathogenicity outbreaks. Some industry associations, such as those on the Delmarva
peninsula (Delaware, Maryland, and Virginia), have compensation funds.
For highly pathogenic outbreaks, USDA has a long-standing regulation allowing
100% indemnification for highly pathogenic outbreaks of avian flu (9 C.F.R. § 53.2).
In 2006, USDA began a new indemnity plan for low pathogenicity avian flu.17
This program (9 C.F.R. § 53.6) will pay up to 100% indemnity for the market value,
destruction, and disposal of poultry destroyed in an outbreak, and for the cleaning
and disinfection of premises, conveyances, and materials. To qualify for 100%
compensation, both the state and the commercial grower must participate in federal
and state surveillance plans; otherwise the compensation rate is only 25%. An
exception allows small growers to receive 100% compensation, regardless of
participation in the surveillance plan. Thus, given expected participation rates among
commercial growers and states, nearly all producers and states will qualify for 100%
indemnification in an H5 or H7 outbreak. Funds for such indemnities likely would
come from the Secretary’s authority in 7 U.S.C. § 8316 to transfer money for animal
health emergencies, most likely from the Commodity Credit Corporation.18
16 USDA APHIS Veterinary Services, “National Highly Pathogenic Avian Influenza
Response Plan,” (Aug. 2006), at [http://www.aphis.usda.gov/newsroom/hot_issues/
avian_influenza/avian_influenza_summary.shtml].
17 A limited indemnification program was created for a 2002 LPAI outbreak in Texas and
Virginia (formerly 9 C.F.R. § 53.11; removed by the new indemnity plan in 9 C.F.R. § 56).
18 For more background on emergency funding for animal health emergencies, see CRS
Report RL32504, Funding Plant and Animal Health Emergencies: Transfers from the
Commodity Credit Corporation, by Jim Monke and Geoffrey S. Becker.

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Economic Impacts
Avian flu can affect the agricultural economy significantly. Because the extent
of such an outbreak is highly uncertain, no quantitative economic estimates of an
H5N1 outbreak in the United States are provided here. Usually, direct costs include
culling birds and quarantining farms. Larger economic effects arise from
international trade bans which affect farms outside the quarantine area.
The 1983-1984 outbreak of highly pathogenic avian flu in the United States
caused the destruction of 17 million birds and cost $65 million. In the small 2004
domestic outbreak, about 400,000 chickens were culled in the United States. While
this was less than 0.02% of U.S. broiler production, the effect on local regions and
farms was much greater. The potential economic impact of a highly pathogenic
H5N1 outbreak in the U.S. likely could be many times larger.
In the current H5N1 outbreak, global consumer confidence is increasingly at
stake despite official statements that normal cooking would kill any virus that might
be present. With strong consumer confidence, demand for healthy poultry may rise.
But weak consumer confidence could depress poultry prices (globally or locally) and
raise demand for substitute meats such as beef or pork. In a recent domestic survey,
46% of chicken eaters said they would stop eating chicken and another 25% said they
would eat less chicken if avian flu entered the United States.19 In 2006, consumer
demand for poultry dropped in Europe and Africa. Lower shipments to Eastern
Europe and Central Asia depressed U.S. poultry prices in 2005.20
Demand for feed such as corn and soybean meal is tied to poultry production.
Poultry accounts for about one-third of world feed use. So far, the global impact on
feed has been limited due to relatively quick recovery of production where outbreaks
were contained, since the production cycle is quite short (about eight weeks).
The United States is the world’s largest producer and exporter of poultry meat
and the second-largest egg producer. About 8.5 billion broilers are produced
annually (Figure 4), worth over $23.3 billion on the farm (22% of farm livestock
sales, and 12% of total farm sales including crops). Broiler production accounts for
about $15 billion, eggs $5 billion, and turkeys nearly $3 billion. Five states account
for 60% of U.S. production: Georgia (15%), Arkansas (14%), Alabama (13%),
Mississippi (9%), and North Carolina (9%). About 16% of U.S. poultry production
is exported.
19 Harvard School of Public Health, “Project on the Public and Biological Security” (Jan.
17-25, 2006), at [http://www.hsph.harvard.edu/press/releases/press02232006.html].
20 FAO, “Escalating bird flu crisis jeopardizes global poultry trade prospects” (Feb. 28,
2006) at [http://www.fao.org/newsroom/en/news/2006/1000240/index.html], and USDA
Economic Research Service, “Livestock, Dairy, and Poultry Outlook,” February 15, 2006
(monthly), at [http://www.ers.usda.gov/publications/ldp].

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CRS-13
Figure 4. Geographic Concentration of Broiler Production
Internationally, the ongoing H5N1 outbreak has affected small poultry farms and
backyard farmers in particular, but also large-scale poultry farms, feed suppliers and
poultry processors. The effects have been particularly acute in certain Asian
countries where culling has been extensive or recurring. In developing countries,
poultry farming represents a significant source of income and wealth. Poultry also
may be an important source of protein, causing nutritional problems if culling is
extensive or prolonged. Many observers have called for greater assistance to
developing countries for compensation programs to encourage early reporting of
outbreaks, rapid containment of the disease, and reductions in trade in diseased
animals.
Legislative Actions
Congressional Hearings
Since the recent outbreak of highly pathogenic H5N1 in Asia, Congress has had
three hearings on avian flu in poultry. The Senate Agriculture Committee held the
most recent hearing on avian flu in poultry on May 11, 2006. It reviewed avian flu
preparedness and the use of appropriated funds.21 Both the House and Senate
Agriculture Committees held more general hearings on avian influenza on November
21 U.S. Senate Committee on Agriculture, Nutrition, and Forestry, USDA Avian Influenza
Plan Review, May 11, 2006, at [http://agriculture.senate.gov/Hearings/hearings.cfm
?hearingId=1869].

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16 and 17, 2005, respectively.22 Administration, industry, and academic witnesses
reviewed prevention and control efforts.
Federal Appropriations to Control Avian Flu
Funding for avian flu is scattered in a number of agencies. For poultry, the
primary agency is APHIS, with some research funds allocated to the Agricultural
Research Service (ARS) and the Cooperative State Research, Education, and
Extension Service (CSREES). For wild birds, the primary agencies are APHIS, the
Fish and Wildlife Service (FWS) and the Biological Research Division in the U.S.
Geological Survey (USGS), two Interior agencies.
Poultry. For FY2007, USDA requested $82 million for avian flu: $77 million
for APHIS and $5.4 million for agricultural research. Of the amount for APHIS,
$56.7 million would be for a new HPAI monitoring and surveillance program, and
$16.7 million for LPAI. The House-passed bill in the 109th Congress (H.R. 5384)
concurred with the LPAI request, but would have provided $9.5 million less than
requested for HPAI. The Senate-reported appropriations bill (H.R. 5384) concurred
with the HPAI request, but would have provided $3 million less for LPAI. Final
action on an FY2007 agriculture appropriations bill has been held over for action in
the 110th Congress. Pending final action, a continuing resolution is funding these
programs at FY2006 levels (see next paragraph), since FY2006 funding is lower than
the House-passed version and the full Senate did not pass a bill. Thus, any potential
increases for avian flu for FY2007 are not available.
For FY2006, the regular appropriation to APHIS for its LPAI program was
$13.8 million (but with carryover, $28.3 million was available, with about $12
million for indemnities; P.L. 109-97, H.Rept. 109-255). In addition, Congress
appropriated $91.4 million in emergency supplemental funds for USDA as part of
$3.8 billion for pandemic influenza (Division B, Title II, of P.L. 109-148). From the
supplemental, APHIS received $71.5 million for domestic surveillance, diagnosis,
and vaccine stockpiles; and for international technical assistance for surveillance,
biosecurity, and control.
In FY2005, Congress appropriated$23.8 million to APHIS for avian flu, with
about half for the indemnity reserve. In FY2004, APHIS received a $1 million
appropriation. USDA also transferred $13.7 million in emergency funds during the
2004 outbreak.
Wild Birds. For FY2007, the Administration proposed to continue the special
supplemental funding of $7.4 million that Congress provided to FWS in FY2006 for
the study, monitoring, and early detection of highly pathogenic avian flu. The
22 U.S. House Agriculture Committee, Review Issues Related to the Prevention, Detection,
and Eradication of Avian Influenza, Serial No. 109-21 (Nov. 16, 2005), at [http://
agriculture.house.gov/hearings/109/10921.pdf]; and U.S. Senate Committee on Agriculture,
Nutrition, and Forestry, The Role of U.S. Agriculture in the Control and Eradication of
Avian Influenza, S. Hrg. 109-508 (Nov. 17, 2005), at [http://a257.g.akamaitech.net/7/257/
2422/25oct20061500/www.access.gpo.gov/congress/senate/pdf/109hrg/28423.pdf].

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Administration request was approved by the full House and the Senate
Appropriations Committee. FWS is to cooperate with other federal and non federal
agencies in studying the spread of the virus through wild birds. Attention is to be
focused on the North American species whose migratory patterns make them likely
to come into contact with infected Asian birds. The geographic focus is to be on
Alaska, the Pacific Flyway (along the west coast), and Pacific islands (see Figure 1).
The House Appropriations Committee report also directed that the funds be used not
only for monitoring and testing in Alaska, but also for “vector control efforts in other
areas,” but did not elaborate on the efforts intended nor the geographic areas to be
given additional emphasis. The Senate report did not discuss the program.
Under the Terrestrial and Endangered Resources sub-activity, USGS is
conducting activities related to HPAI. In cooperation with FWS and other federal
and state agencies, USGS began targeted surveillance for the early detection of HPAI
in wild birds in Alaska in 2005, collecting samples from 520 birds of 10 species that
are known to migrate through the Russian Far East and Southeast Asia. A steering
committee was formed in 2006 to coordinate efforts and establish standard operating
procedures for sampling and analysis. For 2007, the USGS is expected to join with
other partners to continue sampling birds for HPAI and coordinate with other
agencies to deal with avian influenza in North America. The Administration
requested $3.2 million for FY2007 to continue USGS avian flu detection activities.
The House-passed bill and Senate Appropriations Committee bill approved these
increases.
Final action on an FY2007 Interior appropriations bill has been held over for
possible action in the 110th Congress.

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