The United States faces a concerning development as the first outbreak of the rare H5N9 bird flu strain has been reported at a historic poultry farm in Merced County, California. The farm, in operation since the 1640s, detected the H5N9 alongside the more common H5N1 strain. This marks the first confirmed case of Highly Pathogenic Avian Influenza (HPAI) H5N9 in US poultry, according to the US Department of Agriculture. This outbreak comes amidst already challenging times for the egg industry, with average prices for a dozen Grade A eggs in the US doubling from over $2 in September 2023 to $4.16 in December 2024.
“This is the first confirmed case of HPAI H5N9 in poultry in the United States,” – US Department of Agriculture
Since early December, nearly 119,000 birds at the California farm have been culled as a necessary measure to contain the virus. This incident is part of a broader trend of avian flu spreading globally, leading to the culling of hundreds of millions of poultry. The World Organisation for Animal Health (WOAH) recently reported a similar outbreak at a duck farm in California, emphasizing the widespread nature of this issue.
The avian flu crisis is not confined to California. Last week, an outbreak was reported at a duck farm on New York's Long Island, resulting in federal officials ordering the destruction of its entire 100,000 flock. The pervasive H5N1 strain alone has infected or killed 136 million birds worldwide since its outbreak began in 2022, impacting over 900 dairy herds across the US and infecting 67 people.
“The USDA animal and plant health inspection service (APHIS), in conjunction with state animal health and wildlife officials, are conducting comprehensive epidemiological investigations and enhanced surveillance in response to the HPAI related events,” – US Department of Agriculture
The implications of these outbreaks extend beyond poultry. The bird flu has spread to dozens of mammal species, including dairy cows in the US. Earlier this year, a person in Louisiana succumbed to the virus, highlighting its potential threat to public health. The US National Library of Medicine underscores the uncertainty surrounding the novel H5N9 strain's potential to transmit to humans.
“Whether this novel H5N9 virus will cause human infections from its avian host and become a pandemic subtype is not known yet,” – US National Library of Medicine
“It is therefore imperative to assess the risk of emergence of this novel reassortant virus with potential transmissibility to public health.” – US National Library of Medicine
The Centers for Disease Control (CDC) assures that while the current public health risk remains low, they are closely monitoring the situation and collaborating with states to oversee individuals with animal exposures.
“While the current public health risk is low, CDC is watching the situation carefully and working with states to monitor people with animal exposures.” – US Centers for Disease Control (CDC)