Deadly Bird Flu Strain Confirmed in Mississippi Poultry Flock

Deadly H7N9 bird flu has returned to American soil for the first time since 2017, infecting nearly 50,000 chickens in Mississippi and triggering immediate containment efforts to prevent further spread to poultry flocks across the nation.

Key Takeaways

The H7N9 avian flu strain was detected in a commercial broiler breeder chicken flock in Noxubee County, Mississippi, affecting 47,654 birds.
Officials have quarantined the affected area and depopulated the flock to prevent further spread, with none of the infected birds entering the food system.
H7N9 has a concerning global human mortality rate with 616 deaths among 1,568 infections since 2013, though person-to-person transmission remains limited.
The USDA and state officials are conducting comprehensive epidemiological investigations and enhanced surveillance in response to the outbreak.
Experts advise thoroughly cooking poultry and eggs and maintaining good hygiene practices as preventive measures.

First US Outbreak in 8 Years Confirms Deadly Strain’s Return

The World Organization for Animal Health (WOAH) confirmed on March 13 that the H7N9 avian influenza virus has been detected in the United States for the first time since 2017. The outbreak was identified in a commercial broiler breeder chicken flock in Noxubee County, Mississippi, affecting 47,654 birds. The Mississippi Veterinary Research & Diagnostic Laboratory tested samples and confirmed the presence of highly pathogenic avian influenza, triggering immediate containment protocols to prevent further spread of the disease throughout the region’s poultry industry.

Federal and state agricultural officials have implemented strict containment measures, including quarantining the affected area and depopulating the infected flock. The US Department of Agriculture’s Animal and Plant Health Inspection Service (APHIS) has emphasized that none of the infected birds have entered the food supply chain, minimizing potential risk to consumers. This outbreak marks a significant development for America’s poultry industry, which has primarily been battling the H5N1 strain since 2022, an outbreak that has already affected approximately 167 million birds nationwide.

New outbreak of deadly bird flu strain confirmed for first time in 8 years https://t.co/WMLCAXTg4o

— Fox News (@FoxNews) March 20, 2025

The Significant Human Health Concerns

While the current outbreak is contained to poultry, the H7N9 strain carries concerning implications for human health. This particular strain has caused 616 human deaths among 1,568 infections worldwide since it was first identified in China over a decade ago. This represents a mortality rate approaching 40% among those infected. Despite this alarming statistic, health experts emphasize that bird flu strains typically do not transmit easily between humans, with most human infections resulting from direct contact with infected birds or contaminated environments.

Dr. Myles Druckman, global medical director at International SOS in California, notes that H7N9 is a “novel reassortant” formed from three different bird flu strains. Individuals infected with this virus typically develop fever, cough, and can progress to severe respiratory illness. Antiviral medications can help reduce the severity of illness if administered early. The World Health Organization has stated that this strain “is of concern because most patients have become severely ill,” though it “does not appear to transmit easily” between humans.

Containment Efforts and Public Safety Measures

USDA officials have emphasized that the Mississippi case involves a “fully North American” virus that is likely attributable to wild bird transmission and is unrelated to the ongoing H5N1 outbreak. Agricultural authorities have launched a comprehensive response operation. “The USDA Animal and Plant Health Inspection Service (APHIS), in conjunction with state animal health and wildlife officials, are conducting a comprehensive epidemiological investigation and enhanced surveillance in response to the detection,” according to the WOAH report.

For the average American, the risk remains low, according to health officials. Dr. John Whyte, WebMD chief medical officer, advises standard food safety precautions, including cooking poultry and eggs thoroughly to kill any potential virus. He recommends an internal temperature of 165 degrees for poultry products. Additional prevention measures include avoiding live animal markets and birds that appear ill, keeping away from surfaces that might be contaminated with bird secretions, and practicing regular handwashing, according to Druckman. These basic precautions can significantly reduce potential exposure risk to the general public.

Economic Impact and Broader Context

This outbreak comes at a challenging time for American agriculture. The ongoing H5N1 bird flu situation has already caused significant disruption to poultry supplies and contributed to increased food prices across the country. The Trump administration recently announced a five-point plan to address the H5N1 situation, including measures to boost egg imports and fund additional biosecurity protocols on farms. The emergence of H7N9 introduces further complexity to these efforts, potentially requiring additional resources to monitor and contain multiple avian influenza strains simultaneously.

The last US outbreak of H7N9 in 2017 affected poultry operations in Tennessee, Alabama, Kentucky, and Georgia. While that outbreak was successfully contained, it serves as a reminder of the persistent threat avian influenza poses to American agriculture. Of particular concern to health officials is the recently documented spread of bird flu to mammals, including dairy cows in the United States. This expanded host range raises questions about the virus’s potential to adapt and possibly increase transmissibility between species—a development that would require heightened vigilance from both agricultural and public health authorities.