The ongoing bird flu epidemic in the United States is now the longest and deadliest on record. More than 57 million birds have been killed by the virus or culled in the past year, and the deadly disruption has helped propel soaring egg prices and a spike in egg smuggling.
Since highly pathogenic avian influenza (HPAI) A(H5N1) was first detected in US birds in January 2022, the price of a carton of a dozen eggs has risen from an average of from about $1.79 in December 2021 to $4.25 in December 2022, a 137 percent increase, according to data from the U.S. Bureau of Labor Statistics. Although inflation and supply chain issues partly explain the rise, eggs saw the largest percentage increase of any specific food, according to the Consumer Price Index.
And the high prices have some at the US-Mexico border trying to smuggle illegal cartons, which is prohibited. A U.S. Customs and Border Protection spokesperson told NPR this week that residents of El Paso, Texas are buying eggs from Juárez, Mexico because they are “significantly cheaper.” . Meanwhile, a San Diego customs officer has tweeted a reminder amid an increase in egg interceptions that failure to report these agricultural items at a port of entry can result in in penalties up to $10,000.
Yet America’s pain in the dairy aisles of grocery stores probably pales in comparison to some of the devastation reaped from poultry farms. HPAI A(H5N1) has been detected in wild birds in all 50 states, and 47 have reported outbreaks in poultry farms. So far 731 outbreaks in 371 counties. Late last month, two outbreaks in Weakley County, Tennessee affected 62,600 chickens.
With the year-long epidemic, it is the longest bird flu epidemic ever recorded in the United States. And with 57 million birds dead in 47 states, it’s also the deadliest, surpassing the previous record set in 2015 of 50.5 million birds in 21 states.
Although the virus is highly contagious to birds, and often fatal, the risk to humans is low. The Centers for Disease Control and Prevention notes that avian influenza type A (aka avian influenza virus) viruses do not generally infect humans, although they can sometimes do so when people have close contact or prolonged without protection with infected birds. Once in a human, it is even rarer for the virus to jump from human to human.
In the current outbreak, the CDC has tracked more than 5,000 people who have come into contact with infected birds, but found only one case of bird flu in a human. The reported case in Colorado was from a person who worked directly with infected birds and was involved in a cull. The person had mild symptoms and recovered.
Although the current data is heartening, virologists and epidemiologists still fear that influenza viruses, such as avian flu, will mutate and recombine into a human-infecting virus with pandemic potential. A report published in the journal Eurosurveillance on January 19 underscored the concern. Spanish researchers documented an outbreak of bird flu in farmed mink on the northwest coast in October last year. The mink were likely infected by wild seabirds, which had a coinciding wave of infection with the H5N1 viruses at the time. During October, more and more mink fell ill, suggesting mink-to-mink transmission, leading to the culling of the entire colony of almost 52,000 animals from the end of October. .
Notably, the H5N1 virus infecting mink had a rare mutation that could have allowed it to spread to and among mink. Mammal-to-mammal transmission of avian virus alone is remarkable, but is of particular concern in mink, which can act as a viral mixer. As the authors of the Spanish report note:
Experimental and field evidence has demonstrated that mink are susceptible and permissive to avian and human influenza A viruses, leading to the theory that this species could serve as a potential mixing vessel for interspecies transmission between birds, mammals and humans.
As such, the authors state that there is a need to “strengthen the culture of biosafety and biosecurity in this farming system and promote the implementation of ad hoc surveillance programs for influenza A and other zoonotic pathogens globally”.
None of the mink farm workers were infected with the H5N1 virus, the authors report. However, they note that the use of face masks was mandatory for all mink farm workers in Spain following concerns about the spread of SARS-CoV-2. And when an illness was first detected on the farm, workers took precautions in case it was SARS-CoV-2, including the use of disposable coveralls, face shields, a twice-daily mask changes and frequent hand washing, all beginning October 4.