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October 12, 2022

Controlling and Preventing Highly Pathogenic Avian Influenza (HPAI) Spread in the U.S.

by Yasser Sanad

As we are approaching the fall and winter seasons, which provide favorable conditions for viruses such as Influenza virus to become more active, further precautionary actions are needed to avoid recurrence of the disease outbreak like last year.

Avian influenza (AI) is one of the major threats to poultry, and outbreaks cause severe economic losses.  And according to the World Organisation for Animal Health (OIE), Highly Pathogenic Avian Influenza (HPAI) is a viral disease affecting wild birds and birds used as human food like chickens and turkeys. This virus is highly contagious and mammals, including human beings, can transfer the virus [1]. HPAI is the highest pathogenic strain that causes severe medical symptoms and high mortality rates in poultry. The strains are made of two surface proteins: Hemagglutinin (HA) and Neuraminidase (NA). HPAI H5N1 virus was first discovered in poultry in China [1]. The virus’s genome contains mutable RNA molecules that undergo mutation, affecting the host’s genome. Additionally, some subtypes of AI, mainly H5, can cross species barriers and infect mammals. Research shows that wild birds are reservoirs (hosts that transmit pathogens) for these avian viruses and play a significant role in the evolution and control of these viruses’ spread. There is a need to monitor and control avian influenza viruses in poultry in the United States to reduce the virus load in bird species and the environment.

Prevention, control, and elimination are three different important objectives to reduce the spread of avian influenza in the poultry sector in the United States, especially since poultry and its products are one of the primary animal proteins in human food. Various strategies, including biosecurity, surveillance, and others, have been developed to achieve these objectives.

To control and prevent the spread of avian influenza, people need to be educated about the virus and how it is introduced and spread. Consequently, they must understand the risks of contracting it and how to protect themselves, including proper handling. Training should be conducted for everyone, whether they have been exposed to the virus or not. This will help people understand measures already in place if they are exposed to the virus. Individuals should be shown how to conduct appropriate housekeeping practices in their homes and workplaces, personal protective measures such as properly washing and drying their hands, and how to maintain good respiratory etiquette, among other practices. This will ensure that every person knows how to protect themselves from infection. Additionally, employees working in poultry industries should also be enlightened about the symptoms of avian influenza and measures to take in case they suspect that they contracted the virus. The poultry industries should work together to inform each other about an outbreak. A crucial part of responding to an HPAI outbreak is to have appropriate and efficient preparedness, risk communication, and crisis management plans. This is designed to ensure effective, accurate, and efficient communication between the field team and all involved parties, including public communities, farmer unions, stakeholders, and health providers in order to adhere to biosafety guidelines. If everyone appropriately plays their role, achieving control and prevention objectives will be attainable.

The United States Environment Protection Agency (EPA) should also increase the number of registered antimicrobial disinfectants against avian viruses. This will decrease the host’s susceptibility. Although no specific antimicrobial disinfectant against the virus has yet to be produced, the available scientific evidence suggests that available registered products will be effective against this virus. This will ensure that most people in the country will be protected against the virus if they follow the instructions correctly, hence reducing the risk of contracting the virus. Also, public health officials should provide immunization against the virus. The avian influenza virus mutates fast, making it difficult for scientists to develop a vaccine. However, scientists have made a vaccine that can make your body immune to the virus if you get infected. Immunization is meant to introduce the virus to the body; as a result, a rapid secondary immune response is triggered after exposure to the virus. Thus, health authorities should make the vaccine available with periodically updated patches that include the most prevalent strains of the virus. Poultry should also be vaccinated to reduce avian influenza viruses since they are the virus’ main host [2]. The virus vaccine is meant to prevent clinical diseases and mortality rates. However, these vaccinations do not entirely protect the country against infection, especially in the poultry industry. As a result, biosecurity practices are critical to prevent vaccinated flocks from being infected and farmers’ high economic losses.

Additionally, the United States Department of Agriculture should diagnose and monitor birds’ migration. A surveillance program for wild birds would provide an early warning system for the introduction and spread of avian influenza viruses in the United States. The surveillance system that has been conducted by the Animal and Plant Health Inspection Services (APHIS) would enable the poultry industry, stakeholders, and governmental authorities to take timely and swift action to reduce the risk of spreading the virus to our poultry industry and other populations. Further, the eradication of the virus depends on how fast the virus is detected and the measure implemented to eliminate the virus. If a higher mortality rate suggests an exotic infection, research and analysis should be conducted to identify the causative agent. Surveillance helps detect the outbreak early, preventing severe impact from the virus.

Three systems enhance national surveillance in the United States. The first is the National Poultry Improvement Plan, which certifies that poultry interbreeds are free from the virus. The second involves testing the meat before being exported. Last, state programs are used to detect areas with a high risk of contracting the virus. Additionally, such programs should use biosecurity strategies to reduce the risk of introducing the avian virus in agricultural poultry farms by limiting the movement of infected birds to new premises. This is enhanced by restricting movement of birds between states especially from those where the virus is detected.  Other factors are managed by proper disinfection during the cleaning of equipment. The most significant aspect of biosecurity is developing and maintaining biosecurity culture in poultry companies and production facilities. Training programs can be provided for the workers and employees to better understand the procedures and benefits of biosecurity and enhance the employed strategies, therefore preventing and controlling exposure to the virus.

Birds suspected to be infected with the AI virus should be quarantined to prevent further disease spread, and the infected facilities should be eliminated. Beyond this, two systems in particular would enable the elimination of infected poultry flocks. The first is the controlled marketing of the recovered flock, and the second is how to depopulate and dispose of infected flocks on the farm. The elimination program is dependent on producer company procedures such as accessibility to different disposal methods, local, state, and federal agricultural and environmental regulatory policies, and availability of indemnities. Euthanasia and disposal are the most preferred ways to eradicate infected flocks. Euthanasia involves using carbon dioxide in self-contained chambers where the infected flock is placed. Consequently, after euthanasia, the carcass must be disposed of according to available local methodologies and biosafety regulations. The first related methodology is off-farm disposal, which is limited due to public safety and potential contamination of groundwater. The second option is to use wood-burning incinerators to burn the carcasses. These methods, among others, are used to dispose of the carcass. Control strategies for HPAI vary between countries based on the economic capacity of each country. Developed countries usually follow the depopulation strategy for eradication of infections, while low- and medium-income countries use the vaccination strategy for flocks that appear healthy and typically condemn only infected birds.

Moreover, state governments must put programs in place to monitor boundaries to ensure that infected birds from countries experiencing outbreaks do not enter the country illegally. Water bodies should be monitored appropriately to ensure that migrating birds will not move into other countries. Additionally, the government should avoid importing fertile eggs, broilers, or turkeys from countries with a history of the avian virus like Mexico. When such a measure is put in place, it will prevent the spread of the virus [1]. This will reduce financial losses incurred due to the avian influenza virus. The United States has also invested in a related research institution. The avian virus continues to mutate, making it difficult for scientists to develop the appropriate vaccine. As a result, scientists are working to create a vaccine that will fully protect flocks from infection.

In addition to these practices, effective farm and personnel biosecurity is a primary protective measure against the virus. For effective biosecurity, every farm should have its own biosecurity protocol since farms are different. Some recommended procedures include the following tips [3]:

1. Recognizing the signs of illness.

For example – drop in egg production, increased deaths, diarrhea, and no appetite from the flock, among others.

2. Do not bring the disease home with you.

To control and prevent the virus when purchasing birds, a reputable source should be used as well as checking signs of illness in a bird before purchase and having a quarantine pen away from the other flock where you can isolate birds. In case one visits an area where waterfowl are present such as a pond, one should disinfect the shoes, change clothes, and shower before visiting poultry. In the U.S., waterfowl egg auctions should be suspended.

3. Enhancing biosecurity measures.

Limit the movement in and out of infected farms by locking the gates or even having them protected by a guard to adhere to biosecurity policies. USDA/APHIS has provided materials including videos, checklists, and a toolkit about biosecurity for people who are involved with poultry production either on a small scale or for large commercial producers to assure the health of their flocks. The materials are available at:

4. Restricting visitors.

Visitors can accidentally bring in the virus on their shoes or clothes and therefore should not be allowed in poultry pens without disinfecting first.

5. Cleaning and disinfecting.

Poultry should be kept sanitary, clean water should be provided, and the equipment used should be disinfected and cleaned.

6. Controlling vermin and pests.

Wild birds’ entry into poultry pens should be prevented and flock contact with wild bird droppings should be avoided.

7. Depopulate.

Humanely euthanize the affected flock(s).

8. Test and confirm

Test and confirm that the poultry farm is free from AI virus before allowing repopulation.

9. Get assistance.

Since many diseases can be difficult to recognize one should seek help by contacting a local veterinarian, county agents, or extension poultry specialists as available.

10. Personnel hygiene.

Workers and personnel should take extra measures by using personal protection equipment (PPE), such as gloves, goggles, masks, and disposable coveralls to protect themselves from contracting the virus. Any exposed personnel must practice self-quarantine and seek medical assistance if they experience severe flu-like symptoms.  

In conclusion, the avian influenza virus remains a significant global epidemic threat, causing the economy to scrabble. Acceptance and application of the strategies put into place by the federal government will help control and prevent the virus from spreading. However, the federal government should include financial incentives for rapid outbreak detection and elimination. The virus’ variability makes it hard for scientists to develop a vaccine with permanent effects. Therefore, we recommend that the federal government should allocate more funds for scientific research. Due to this variability, it is important to continue monitoring the spread of the virus, especially in countries that experience wild bird migrations. Applying the above strategies will assist in controlling the spread of the virus.


[1] Mansour, S. M., Ali, H., Chase, C. C., & Cepica, A. (2015). Loop-mediated isothermal amplification for diagnosis of 18 World Organization for Animal Health (OIE) notifiable viral diseases of ruminants, swine and poultry. Animal Health Research Reviews16(2), 89-106.

[2] Chung, D. H., Torchetti, M. K., Killian, M. L., Swayne, D. E., & Lee, D. H. (2022). Transmission Dynamics of Low Pathogenicity Avian Influenza (H2N2) Viruses in Live Bird Markets of the Northeast United States of America, 2013-2019. Virus Evolution.

[3] Clark, F. D. (2022). Avian Influenza Update: Poultry Biosecurity Practices.


Yasser Sanad

Yasser Sanad


Yasser is the EIDHS zoonotic and One Health technical advisor. He brings extensive experience in virulence factors and microbial pathogenesis of infectious pathogens and zoonotic diseases from animals, humans, and environmental sources to provide expert guidance on One Health strategies and activities.

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