h5n1 avian influenza: global spread, cross-species transmission, and pandemic potential (2022-2024)

The h5n1 avian influenza virus continues to pose significant risks to both animal and human populations. from 2022 to 2024, the virus has been detected in over 9,300 wild birds and 1,140 flocks in the u.s., with outbreaks reported across 48 states. globally, it has spread to mammals, including sea lions, mink, and polar bears. transmission to humans remains rare, with only 29 cases reported worldwide during this period. however, these cases often result in severe illness or death, with seven fatalities recorded. in animal models, h5n1 s cross-species transmission has been a concern, particularly in ferrets, which are often used to study human influenza. studies have shown that while transmission between co-housed animals occurs, airborne spread is less efficient. nonetheless, all infected ferrets in one study succumbed to the disease, emphasizing the virus s lethality.despite its limited transmission between humans, the widespread circulation of h5n1 among birds and mammals raises concerns about potential mutations that could enable easier human-to-human transmission. previous pandemics, such as h1n1 in 2009, originated from similar zoonotic events. moreover, while no vaccine exists specifically for h5n1, ongoing surveillance and control measures are critical to prevent a future pandemic. in conclusion, h5n1 remains a global threat, requiring continued vigilance and research to understand its evolving nature and mitigate its risks.