Breaking down the current status of H5N1 avian flu in the US: March 2025

The highly pathogenic avian influenza (HPAI) H5N1 virus continues to spread among multiple species across the Unites States, including birds, wild animals, and domestic livestock, raising concerns about potential human exposures and public health risks.

The evolution of H5N1 in North America has been marked by increasing reassortment events, human cases, and spillovers into new species, including dairy cattle. Most notably in February 2025, genotype D1.1 was first detected in dairy cattle (previous cases in cattle were due to B3.13). Sporadic infections in humans continue.

H5N1 continues to expand its reach, with rising detections in wild birds, poultry, and mammals. Human cases remain limited and are linked to direct exposure to infected animals. Risk to the general public in the US is low. Those potentially exposed to infected animals or contaminated surfaces/fluid are considered to be at moderate to high risk. Societal and economic impacts of the H5N1 outbreak are becoming more noticeable.

Genetic analysis shows two dominant H5N1 lineages of Clade 2.3.4.4b, B3.13 and D1.1, circulating in North America, with evidence of cross-species transmission.

Recent human cases in Nevada and Wyoming were linked to the newer D1.1 genotype and carried mutations that may enhance adaptation to mammals. The concern is whether increased mammalian adaption will produce a virus capable of sustained human-to-human transmission. No antiviral resistance has been detected. Vaccine readiness remained unchanged.

H5N1 outbreaks among poultry farms (and the resulting mass culling events) have led to egg shortages and rising prices, with concerns that some companies may be leveraging the crisis for profit.

While human-to-human transmission has not been observed, ongoing infections in livestock and wildlife increase opportunities for viral adaptation. A coordinated response for pandemic preparedness is critical.

You can reduce your risks associated with HPAI H5N1 by practicing good hygiene, avoiding contact with sick animals, and staying informed through credible sources.

The key takeaway is this: While sensational headlines and fear-driven narratives may run rampant and should be recognized as such, the situation does warrant concern. Particularly regarding the administration’s commitment protecting public health and HHS’s ability to manage their response effectively. However, the overall risk to the general public remains low. The real question is whether the virus will acquire a mutation that enhances its ability to infect humans more efficiently. It's a crap shoot, really. What we can control is slowing its spread and reducing opportunities for such mutations to emerge.