Overview of HPAI

Image of a broiler chicken and related signs of Avian Influenza

Highly Pathogenic Avian Influenza (HPAI), commonly known as Bird Flu, is a highly contagious and deadly viral disease that predominantly impacts birds, specifically domestic poultry like chickens and turkeys. It is caused by a virulent subtype of the Influenza type-A virus, resulting in rapid spread and significant mortality within affected poultry flocks. While this virus causes severe illness and high mortality in domestic poultry, it is naturally present in various wild aquatic birds, including ducks, geese, swans, and shorebirds.

For more information including:

  • A more in-depth overview;
  • Subtypes of Avian Influenza;
  • Clinical Signs of HPAI;
  • How to protect your flocks from HPAI;
  • How to report the suspect HPAI infection in your flock;

Please visit this resource page.                           

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Test & Surveillance

Collection of Swab Samples from HAPI Suspected Birds

The current gold standard for diagnosing and monitoring Highly Pathogenic Avian Influenza (HPAI) is the reverse transcription polymerase chain reaction (rRT-PCR) test. Sample collection for this test must be carried out by Category II Accredited Veterinarians, Agents of the State, or Maryland Authorized Poultry Testing Agents.

When sampling gallinaceous poultry, including chickens, turkeys, pheasants, and quail, it is recommended to take an oropharyngeal or tracheal swab. For domestic waterfowl, such as ducks and geese, a cloacal swab should be collected.  The Maryland Department of Agriculture has two animal health diagnostic laboratories for animal disease investigation - in Salisbury and Frederick. It is recommended for the producers to contact these laboratories prior to the submission of samples. 

Active surveillance of poultry flocks is carried out around the region of the HPAI outbreak to check the spread of the disease. Furthermore, producers must carry out pre-movement surveillance of the flock in order to obtain permit for moving poultry products from the outbreak region. 

For more information including:

  • Maryland Department of Agriculture Guidelines for proper sample collection;
  • Surveillance of HPAI;
  • Laboratory submission;

Please visit this resource page.


Risk factors of HPAI

Biosecurity refers to a range of measures and practices designed to minimize the occurrence, transmission, and impact of infectious diseases such as Highly Pathogenic Avian Influenza (HPAI) within poultry populations. It plays a pivotal role in preventing HPAI outbreaks among poultry flocks. HPAI can infiltrate poultry flocks through two primary routes: direct contact with infected birds or indirect transmission via humans, feed, water, equipment, or rodents. Implementing comprehensive biosecurity measures to combat HPAI effectively disrupts the transmission chain along these pathways.

For more information including:

  • A deeper biosecurity overview
  • Risk Factors of HPAI in Commercial Broiler Flocks
  • General biosecurity measures against HPAI
  • Addressing the risk of HPAI in free-range poultry flock
  • Important biosecurity links

Please visit this resource page.                                             -image edited with BioRender


A truck with permit stamped on its side

Quarantine and movement restriction are employed as a primary tool to stem the further spread of HPAI in the United States. During HPAI outbreak, movement of poultry and poultry products is only allowed  from the premises which have approved biosecurity measures in place and can produce HPAI-negative test result for the flock. This permitted movement allows for the continuity of poultry industry and security of the food supply in the US. Poultry growers in the state of Maryland can request for movement permit through USDA Emergency Management Response System 2.0 (EMRS2) Customer Permt Gateway. 
For more information including:

  • Response to HPAI and designation of control area;
  • What is a permit and who issues the permit for poultry movement?
  • Do all products require permit to move?
  • How to initiate permit request;
  • Requirements to obtain a movement permit;
  • How does the Secure Poultry Supply (SPS) plan help in the permitting process?

Please visit this resource page.

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Maryland HPAI Resources

Federal HPAI Resources

HPAI in Neighboring States

HPAI Zoom Discussion with Maryland Poultry Experts

Notes from the HPAI Zoom Discussion

Recording of the HPAI Zoom Discussion

Avian Influenza Warning Discussion

Held Feb. 25, on Zoom, Dr. Nathaniel Tablante, DVM, and Extension Poultry Health Specialist, discussed what it is, where it is, how to protect your flock, commercial or backyard.  See below for full video, pdf slides, and the links for commercial and small flock in Notes.

Dr. Tablante's pdf slides:  Avian Influenza: What You Need to Know, Not Fear

The recording:

NOTESAvian Influenza Warning Discussion, February 25, 2022

Disinfection in On-Farm Biosecurity Procedures

Revised by Dr. Gustavo M. Schuenemann, D.V.M., Associate Professor, Extension Veterinarian, Dairy, Department of Preventive Medicine, College of Veterinary Medicine  Original authors: Dr. Gary L. Bowman and Dr. William P. Shulaw

Since the appearance of recent swine and avian influenza outbreaks in the United States as well as foot-and-mouth disease (FMD) in Europe in early 2001 has caused many livestock owners serious concern; many are continuing to look more closely at their biosecurity plans or their efforts to keep the diseases out of their herds or flocks. Over the years, Extension veterinarians have received many calls regarding which disinfectants to use on shoes, boots, tires or other equipment in order to kill the FMD or influenza virus. A few important points about disinfection should be made before choosing a disinfectant for routine farm use.  

First, most disinfectants won’t work if the surface to be disinfected isn’t clean (presence of organic matter such as dirt or manure) before applying the disinfectant.

Steam and high-pressure washers can be very useful to clean porous surfaces. Organic materials such as soil, plant debris (like straw), milk, blood, pus and manure often inactivate some disinfectants or protect germs from the disinfectant’s active ingredients. Chlorine-based disinfectants are especially subject to this problem. Chlorine, the active ingredient in bleach, is relatively quickly inactivated by organic debris such as manure, and even milk, at the concentrations usually used on clean surfaces. Read more.

Useful Resources on Avian Influenza

For current status of A.I. in Maryland, see the Bird Flu Blog and follow @MdBirdFlu on Twitter.

Also, see the Bird Flu Press Kit.

Latest News


Can HPAI affect humans?

While HPAI primarily affects birds, some strains can potentially infect humans. It is crucial to handle infected birds with care and follow health and safety protocols when dealing with sick poultry.

Is there a vaccine available for use against HPAI in commercial Poultry?

In the United States, there are no approved vaccines available for use against HPAI in commercial poultry. Although some countries have implemented vaccination strategies to mitigate the impact of HPAI, the current approach in the US involves depopulating infected flocks and implementing strict movement control measures.

What is HPAI Control Area?

A HPAI Control Area is a designated geographic region or area where strict control measures are implemented to prevent the spread of HPAI in poultry populations. The Control Area comprises of Infected Zone and Buffer Zone. The perimeter of the Control Area is at least 7 km beyond the perimeter of the Infected Zone, which in itself radiates at least 3 km from the infected premises. 

What does it mean when a Control Area is released?

When a Control Area is released, it means that certain conditions have been met after its establishment due to the detection of HPAI in poultry. Poultry farms outside the remaining Control Areas and not under quarantine are no longer subjected to movement controls and surveillance testing. To determine if a specific address is still within a Control Area, check the USDA APHIS website

Which Control Area(s) have been released?

Information about the Control Areas that have been released and those that remain active can be found on the APHIS HPAI 2022 Confirmed Detections website. It is important to note that Control Areas associated with neighboring infected farms may overlap with a released Control Area. Farms within the overlapping Control Areas are still subject to restrictions until their status changes. Please refer to the information on USDA APHIS site and consult with State Animal Health Officials.

What does it take to get a Control Area released?

To get a Control Area released, all infected premises within the area must complete 100% depopulation and proper disposal of birds, feed, litter/manure, and eggs according to the flock plan. Additionally, initial virus elimination and surveillance testing must take place. If there are no positive results on surveillance within the Control Area for 14 days after depopulation and virus elimination, the Control Area can be released.

Can farms that are now outside a Control Area resume normal farming practices?

Yes, farms that are outside a Control Area and not under quarantine can resume normal farming practices without movement controls and surveillance testing. However, it is important for all farms, regardless of location, to continue implementing strict biosecurity procedures to ensure the health of the birds and prevent the spread of HPAI.

Can birds be restocked at infected premises that were within the released Control Area after release?

No, birds cannot be immediately restocked at infected premises within a released Control Area yet. Before restocking, the infected premises must meet all requirements of the flock plan, including quarantine release and obtaining negative results on environmental testing. They must also be outside the infected zone of another flock. Refer to the USDA APHIS guidelines for additional information.

How long does it take to obtain a permit?

Many permit applications are completed within a few minutes to a few hours, some others involving other states may take longer. This includes both movements incoming to Maryland from other states and outgoing from Maryland, so it varies according to who are involved.

How many permits are required?

The number of permits depends upon the types of movement items and the number of movement destinations. Multiple destinations require multiple permits and multiple items also require multiple permits. Producers need to enter the movement into the EMRS2 Gateway before the movement occurs along with the accession number of HPAI test result.