Highly pathogenic avian influenza (HPAI or the bird flu) is a well-known disease commonly found in poultry, capable of wiping out an entire flock within a few days. Although this disease has been on poultry farmers’ radars for many years, there have been recent outbreaks in dairy cattle and humans that are cause for concern.
Brook Duer, a staff attorney with Penn State’s Center for Agricultural and Shale Law, is well educated on the outbreak of HPAI in poultry as well as dairy cattle.
In 2014-15, there was a HPAI outbreak concentrated in turkeys, resulting in 50 million U.S. birds being depopulated or dying from complications of the disease. HPAI was detected in commercial birds, backyard flocks, wild captive birds and/or wild birds.
At that time, USDA’s Animal & Plant Health Inspection Service (APHIS) declared that the outbreak was “the largest HPAI outbreak ever recorded in the United States and arguably the most significant animal health event in U.S. history.”
Although the 2014-15 outbreak was stressful and detrimental, there were many lessons learned to make the industry more prepared for the current outbreak of HPAI. Duer said “there’s been a lot of changes” in the ways people expect a large poultry house/operation to be depopulated, for instance.
The new HPAI outbreak, which started in February 2022, is a different strain (HPAI H5N1) than that encountered 10 years ago (HPAI H5N2 or H5N8). Since 2022, “the total number of birds affected over the course of this entire outbreak… is about 99 million” – 57% of which were from backyard flocks.
Duer explained that the number of birds depopulated from this new outbreak is because “everybody learned from the 2014-2015 outbreak that you’ve got to move fast … and that depopulation is the way to go.”
Until this spring, the U.S. was keeping the HPAI outbreak to “a predictable and manageable occurrence rate,” explained Duer. However, in March 2024, things became a lot more difficult to manage – HPAI was identified in American dairy cattle for the first time.
As of July 2024, there have been 12 states with detected dairy cattle (a total of 152 cases). A positive note is that “we’re not getting large numbers of cows on any individual farms,” Duer said, and the virus is not fatal in cattle. Therefore, depopulation has not been necessary on infected dairy farms.
The National Veterinary Laboratory System conducted a genotype analysis to determine when and where there was a mutation that allowed the virus to spread to dairy cattle. It was determined that “it was a one-time event” when the virus successfully spread from poultry to dairy cattle, and now is spreading from cow to cow.
“The primary transmission of this particular strain is though lactation… The suspicion is it’s probably transferring through milking machinery,” Duer said. This helps to explain why the virus has not been found in beef cattle, and why the disease isn’t spreading rapidly like it would with a respiratory virus.
Another concerning aspect of this HPAI outbreak is that humans are being infected by the virus. Duer said that at the start of July 2024, “there had only been five detections of H5N1 Influenza A in humans” in the U.S. since 2022. By the middle of July, there were five new human cases in Colorado alone. The disease has been mostly seen in dairy workers, due to their exposure to the infected milk. The main symptom seen in infected humans is conjunctivitis and pink eye, with some cases showing respiratory symptoms.
Since this outbreak is not concentrated in the U.S. alone, disease regulation is controlled through APHIS. Although the APHIS Veterinary Service Program administers 12 laws, the Animal Health Protection Act (AHPA) is their main focus. AHPA tries to “prevent and eliminate burdens on interstate commerce and foreign commerce.” Although states have authority on interstate regulations, they rely on USDA for technical assistance, research, resources and funding.
AHPA restricts all imports, exports and interstate movements in order to regulate pests and disease in livestock. APHIS can issue orders, promote regulations, prohibit the import, entry and movement of animals and order the destruction, removal or disinfection of any animal, article or means of conveyance. APHIS can use any of these methods to prevent the introduction into or dissemination within the U.S. of any pest or disease of livestock.
In addition to the standards of APHIS, there are actions allowed in cases of an emergency. However, APHIS can only get involved if it is determined that the measures being taken by the state are inadequate to control or eradicate the threat. If the Secretary of Agriculture determines an emergency exists and APHIS must intervene, they may take action by holding, seizing, treating or taking other remedial actions to destroy or dispose of any animal, article, facility or means of conveyance to disseminate the pest of disease, including preventative slaughter.
AHPA requires that the Ag Secretary compensate the owner of any animal(s) USDA requires to be destroyed, based on fair market value. (Sick animals do not have a market value, so they will not be compensated for.) Compensation would be the case if there was preventative slaughter or similar.
Duer added that to his knowledge, “every single item of poultry that was depopulated in the 2014-2015 outbreak, or the current one that started in 2022, was technically depopulated through an agreement … that was signed by the animal owner, the operator of the poultry operation, or both.”
If the owner violates this agreement, such as moving or handling an animal planned to be euthanized, no compensation will be granted.
APHIS’s authority regarding HPAI can be found in the HPAI Response Plan, also known as “the Red Book.” The Red Book is not a law – it provides guidance to help farmers prepare for and respond to outbreaks of disease.
APHIS created these Red Books for any disease they anticipate rising in the U.S. Currently, four books exist: for HPAI, foot-and-mouth disease (FMD), classical swine fever (CSF) and Newcastle disease (ND).
For more information on APHIS’s Red Books or the Foreign Animal Disease Preparedness & Response Plan, visit aphis.usda.gov/animal-emergencies.
by Kelsi Devolve
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