HPAI News: Jan 6 2025
Map shows outbreaks of HPAI in Dec 2024 (USDA-APHIS)
Executive Summary
Avian influenza didn’t take a break for the holidays, with continued reports of cases in both wild and domestic species. For now, human case numbers are holding steady at 66. Public concern is growing, especially with the recent deaths of pets in California and Oregon. As with any issue that impacts the general public, conspiracy theories and outright denials have begun to surface as well and will need to be managed carefully to prevent further erosion of trust in the agriculture industry. Good news appeared on the scientific front, however, with studies suggesting that some individuals might have pre-existing immunity to the H5N1 virus.
Statistics
In the past 7 days, APHIS has reported positive HPAI tests in 3 wild birds, 5 dairy cow herds, and 20 poultry flocks (1-3). Posting of new cases seems to have lagged due to the holidays, however, as additional cases have been documented in the news. Outbreaks have been seen in Indiana (turkeys), Ohio (wild birds), California (domestic cats), Delaware (poultry) and West Virginia (poultry) (4-8). Of note is the finding of almost 200 dead snow geese in eastern Pennsylvania, raising concerns about how to handle potential mass die-offs of wild birds (9).
Government and Policy
On Dec 30 the USDA announced an interim rule intended to reduce the number of re-infections of poultry farms affected by HPAI. Under the new rule, which will go into effect as soon as it is published in the Federal Register, farms must undergo a biosecurity audit prior to restocking or receiving an indemnity payment for condemned birds. Since 2022, over $365M has been paid to farms that have been infected two or more times (10).
Health and Human Services announced a $306M allocation of funds to support additional monitoring and response efforts for avian influenza. The majority of this funding will go towards hospitals and treatment centers, while just over $100M will be designated for surveillance and diagnostics. The remainder will be distributed by the National Institutes of Health for continued research on avian influenza (11).
Iowa Governor Kim Reynolds extended the State of Emergency declaration for 5 counties through Feb 1 2025 (12).
Public Impact
Authors of a 2024 paper titled “Proximal Origin of Epidemic Highly Pathogenic Avian Influenza H5N1 Clade 2.3.4.4b and Spread by Migratory Waterfowl” have suggested that the USDA’s Southeast Poultry Research Laboratory was the origin of the current genotype of H5N1 virus circulating in the United States. The paper, which was published in the peer-reviewed journal Poultry, Fisheries, and Wildlife Sciences, suggests that further investigation is needed to confirm these speculations (13). An accompanying blog post by the authors, however, demands a criminal investigation into the matter (14).
The USDA reports that egg prices in California (benchmark, large shell eggs) have reached nearly $9.00/dozen. The nationwide average for loose, large shell eggs is $4.85/dozen (15).
Science
A study was recently published in the New England Journal of Medicine describing the clinical cases of 46 poultry and dairy farm workers who contracted H5N1 (16). Among a number of interesting findings was the description of PPE use in the infected workers. Use of PPE varied from over 70% (gloves) to less than 10% (respirator). The reason(s) underlying these results are unclear, but could be due to lack of supplies, cost of biosecurity measures, or practical difficulties in implementation. US farm workers represent a vulnerable population that are placed at risk due to their close proximity to potentially infected animals; providing preventative, diagnostic, and therapeutic support could have a significant impact on reducing animal to human transmission of H5N1.
An article recently published in mBio, a peer-reviewed journal from the American Society of Microbiology, suggests that people who have previously been exposed to seasonal influenza viruses could exhibit some level of immunity against H5N1 (17, 18). The study examined portions of both the avian and human viruses that are recognized by the immune system and found that there is significant similarity between the two pathogens. Although confirmatory studies will need to be done, this suggests the possibility that an avian influenza pandemic could be mitigated by pre-existing immunity in some segments of the global population.
The National Institutes of Health (NIH) has published an updated risk assessment for avian influenza (19). While maintaining that the risk to the general public remains low, the authors stress the need for vigilance, robust surveillance, cooperation among stakeholders, and continued development of vaccines and treatments.