Deadly Bird Flu Strain Reported in the US for the First Time Since 2017

A deadly H7N9 bird flu strain has emerged on a poultry farm in Mississippi for the first time since 2017, prompting swift quarantine measures.

Quick Takes

An outbreak of H7N9 bird flu was detected in a commercial broiler breeder chicken flock in Noxubee County, Mississippi, affecting 47,654 birds.
H7N9 bird flu has a concerning human mortality rate globally, with 616 deaths out of 1,568 infections since 2013.
The affected farm has been quarantined and birds are being depopulated to prevent further spread.
Officials confirm no infected birds have entered the food system.
Experts note the virus doesn’t easily transmit between humans.

First U.S. H7N9 Outbreak Since 2017

The World Organization for Animal Health confirmed on March 13 that the highly pathogenic H7N9 bird flu strain has infected a commercial broiler breeder chicken flock in Noxubee County, Mississippi. This marks the first reported occurrence of this specific strain in the United States since 2017, when outbreaks were detected across Tennessee, Alabama, Kentucky, and Georgia. The current outbreak has affected 47,654 birds, according to official reports. The Mississippi Veterinary Research & Diagnostic Laboratory tested samples from the flock and confirmed the presence of highly pathogenic avian influenza.

The World Animal Health Organization reported that the virus detected is of North American wild bird lineage. “Highly pathogenic avian influenza (HPAI) H7N9 of North American wild bird lineage was detected in a commercial broiler breeder chicken flock in Mississippi. Depopulation of the affected flock is in progress,” the organization stated in their official report. The U.S. Department of Agriculture describes the Mississippi case as “fully North American” and likely introduced by wild birds, making it genetically distinct from the more widely discussed H5N1 strain that has affected dairy cows.

Deadly bird flu strain confirmed in US for first time in 8 years https://t.co/a4T64orUMV pic.twitter.com/BM9QUWdy7a

— New York Post (@nypost) March 20, 2025

Containment Measures Underway

Authorities have acted swiftly to prevent the spread of the virus. The affected farm has been placed under quarantine, and officials are conducting a comprehensive depopulation of the flock to mitigate the risk of transmission to other poultry operations. The USDA’s Animal and Plant Health Inspection Service (APHIS), together with Mississippi state officials, has initiated an epidemiological investigation and enhanced surveillance in the area. Officials confirmed that none of the infected birds have entered the food supply chain, addressing potential public concerns about food safety.

The containment approach follows established protocols for managing avian influenza outbreaks in commercial poultry operations. Preventing the spread is crucial not only for protecting other flocks but also for minimizing economic impact on the poultry industry. Avian influenza outbreaks have previously disrupted global poultry supplies and contributed to increased food prices. This latest incident comes amid an ongoing and more widespread H5N1 outbreak that has affected approximately 167 million birds across the United States since 2022.

Human Health Implications

While the H7N9 strain’s appearance in poultry is concerning from an agricultural standpoint, health experts emphasize that the risk to the general public remains low. The H7N9 strain has a concerning human mortality rate globally, with 616 deaths from 1,568 human infections since it was first identified in China in 2013. However, experts note that bird flu viruses typically do not spread easily between humans. Most human infections historically have occurred through direct contact with infected birds or contaminated environments.

Dr. John Whyte of WebMD advises the public to take basic precautions when handling and preparing poultry products. “You definitely want to cook poultry, and you definitely want to make sure you cook eggs, typically at an internal temperature of about 165 degrees,” he recommends, according to Fox News Digital. Dr. Myles Druckman of the International SOS in California also notes the importance of handwashing and avoiding contact with birds and bird droppings. The World Health Organization has previously noted that the H7N9 strain “is of concern because most patients have become severely ill” but also that it “does not appear to transmit easily” between humans.