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HPAI Response 

Control Area Release

May 20, 2022

Please note: These procedures may be revised as the situation develops.

BACKGROUND INFORMATION 

Release of the Control Area also relates to other highly pathogenic avian influenza (HPAI) 

response activities that are not covered in this document. For information on restocking approval, 

please see Timeline, Eligibility, and Approval for Restocking. For information on environmental 

sampling, please see Post Cleaning & Disinfection Environmental Sampling Guide. The document 

HPAI Zones and Premises provides an overview of the designations used in an HPAI response. 

These documents can be found at www.aphis.usda.gov/fadprep. 

GENERAL GUIDANCE

Release of the Control Area (including the release of associated movement controls and permit 

requirements) is allowed when all the following conditions have been met: 

♦ The Infected Premises that established the Control Area has been depopulated; the 

compost pile has been set (capped), or mortality buried, or mortality removed from 

premises for appropriate disposal. 

♦ Initial virus elimination activities on the Infected Premises are completed (including, but not 

limited to, outside areas of premises, equipment, trucks, and other potential fomites used 

in depopulation and disposal activities). This does not include barn interiors.

♦ Required outbreak surveillance in the Control Area (commercial premises and backyard 

premises) has been completed; there is no evidence of HPAI infection in the Control Area. 

If there is a detection, then the Control Area can still be released if a new Control Area is 

established around the detection.

♦ Each Control Area is released on its individual timeline. In the case of multiple Control 

Areas, premises that are in overlapping Control Areas (premises physically located in 

more than one Infected/Buffer Zone) will follow the timeline for the last Control Area 

scheduled for release. See the example in Figure 1 where a premises is located in 

overlapping Control Areas. 

♦ Surveillance requirements for international or bilateral trade are conducted and may 

continue. 

If it has been 14 days since depopulation and initial virus elimination activities have been 

completed on the Infected Premises that established the Control Area, AND these 

conditions have been met, the Control Area may be released. 

Figure 2 shows a timeline for the release of the Control Area.

The Control Area may be released prior to the date in which restocking is allowed on the 

Infected Premises. 

These requirements may be modified during an incident.
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Figure 1. Overlapping Control Areas 

Figure 2. Release of Control Area

IP Quarantined

IP Depopulated

Initial Virus Elimination 

Activities Completed on IP

14 Days

Control Area Released when All 

Conditions have been met and 

Surveillance Completed with Negative 

Results 

Before starting surveillance for 

Control Area release, mortality 

should be buried, or compost pile set 

(capped), or mortality removed from 

premises for appropriate disposal

IP Confirmed Positive

Quarantines for Non-Infected 

Premises in the Control Area that 

are Not Located in an 

Overlapping Control Area may be 

Released by State

Surveillance for Trading 

Partners & Disease 

Freedom May Continue 

IP Disposal

Length of disposal process 

depends on method used (i.e., 

burial, compost, landfill, etc.).

Control Area 

Established

The Control Area may be released prior to the date in which restocking is allowed and the 

quarantine released on the Infected Premises. Information on Infected Premises timeline, 

eligibility, and approval for restocking and quarantine release is provided in separate 

guidance and can be found at www.aphis.usda.gov/fadprep. 

SURVEILLANCE INFORMATION

Note: IP=Infected Premises

BEFORE: Two Infected Premises (IP1 and IP2) with 

overlapping Control Areas (Control Area 1 and Control 

Area 2, respectively). 

AFTER: The Infected and Buffer Zones of Control Area 1

are released. A Premises previously located in the Buffer 

Zone of Control Area 1 remains on Control Area 2’s 

timeline for release. 
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For more information on surveillance for proof of disease freedom for both commercial and backyard 

premises in the Control Area (Infected Zone and Buffer Zone) and Surveillance Zone, please see the

following (www.aphis.usda.gov/fadprep):

♦ HPAI Response Plan, Appendix D 

♦ Surveillance of Backyard Flocks Around Infected Premises

♦ Surveillance Sampling for Commercial Premises in Control Area

SURVEILLANCE FOR INTERNATIONAL & BILATERAL TRADING PARTNERS

Enhanced surveillance for international and bilateral trading partners may be necessary both prior to 

and after the release of the Control Area. The extent, frequency, and type of enhanced surveillance 

required will depend on many factors, such as (but not limited to) the density of poultry in the region, 

epidemiological information, species, and commodity exported.

The objective of this surveillance is to provide evidence of the absence of HPAI infection to satisfy 

international and bilateral trading partners. Active and passive surveillance schemes may be used.

RECOVERY OF HPAI-FREE STATUS IN THE STATE OR COUNTRY

While the World Organisation for Animal Health (OIE) does not grant official recognition for freedom 

from HPAI, the United States can self-declare freedom and submit all relevant documentation and 

evidence of freedom, per the OIE Terrestrial Animal Health Code to the OIE in order to demonstrate 

freedom to trading partners.

The OIE defines a country or zone free from infection with HPAI viruses in poultry as follows (Article 

10.4.3):

A country, or zone may be considered free from infection with high pathogenicity avian influenza 

viruses in poultry when: 

1. Infection with high pathogenicity avian influenza is a notifiable disease in the entire country;

2. There is an ongoing awareness program to encourage reporting of suspicions of high 

pathogenicity avian influenza; 

3. When, based on surveillance in accordance with Articles 10.4.26 to 10.4.30, it has been shown 

that infection with high pathogenicity avian influenza viruses in poultry is absent in the country 

or zone for the past 12 months, although its status with respect to low pathogenicity avian 

influenza viruses may be unknown; 

4. An awareness program is in place related to avian influenza viruses risks and the specific 

biosecurity and management measures to address them; 

5. Commodities are imported in accordance with Articles 10.4.7 to 10.4.22. 

Surveillance should be adapted to parts of the country or existing zones depending on historical 

or geographical factors, industry structure, population data and proximity to recent outbreaks or 

the use of vaccination. 

If infection has occurred in poultry in a previously free country, the free status in the State or 

country can be regained after a minimum period of 28 days (i.e., two flock-level incubation 

periods) after a stamping-out policy (including disinfection of all affected establishments) is 

applied, providing that surveillance in accordance with Article 10.4.28 has been carried out 

during that 28-day period. 

Articles 10.4.26 and 10.4.30 provide broad information on surveillance and the interpretation of 

positive test results. As stated in Article 10.4.26, “The impact and epidemiology of avian influenza 

differ widely among different regions of the world and therefore it is impossible to provide detailed

recommendations for all situations. Variables such as the frequency of contacts between poultry and 

wild birds, different biosecurity levels and production systems, and the commingling of different 

susceptible species including domestic waterfowl, may require different surveillance strategies to 

address each situation.” A science-based approach should be used to demonstrate disease freedom.
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