Highly Pathogenic Avian Influenza Detected at Seosan Duck Farm: 28,000 Ducks Culled Amid Emergency Response

Background and Initial Detection

On June 14, 2025, at around 1:30 PM, a highly pathogenic avian influenza (HPAI) suspected case was reported at a meat duck farm located in Gobuk-myeon, Seosan city, South Chungcheong Province. The farm had submitted pre-shipment samples the day before to the Animal Hygiene Testing Laboratory, which confirmed the presence of H5 subtype avian influenza antigen. This prompted immediate notification to the Seosan city authorities and the Animal and Plant Quarantine Agency for further confirmatory testing.

Farm Scale and Immediate Measures

The affected farm consists of 14 poultry houses housing approximately 28,000 meat ducks. Upon detection, the city government implemented emergency biosecurity measures including culling all ducks on the farm, thorough disinfection, and removal of contaminated materials. The farm owner was restricted from accessing the premises, and movement of people and vehicles was tightly controlled to prevent virus spread.

Regional Impact and Quarantine Zones

Within a 3 km radius of the infected farm, 17 other farms raising 164 poultry were identified, and this expanded to 116 farms with over 200,000 poultry within a 10 km radius. Consequently, Seosan city imposed a strict 10 km radius quarantine zone, banning animal movement and enforcing biosecurity protocols across all affected farms. An initial emergency response team was deployed to manage the situation and enforce these restrictions.

Historical Context and Risk Factors

Notably, this farm had previously experienced an avian influenza outbreak on November 25, 2024. The farm was restocked in May 2025, and the virus was detected again during routine pre-shipment testing. This highlights the ongoing vulnerability of poultry farms to recurrent AI outbreaks and the critical need for vigilant monitoring and biosecurity.

Community and Government Response

Seosan city officials, including the deputy mayor and relevant department heads, convened an urgent meeting to coordinate the response, share updates, and plan further prevention strategies. The city is mobilizing over 50 contracted personnel to carry out the culling and sanitation operations. Authorities are urging local poultry farmers to conduct voluntary disinfection and citizens to avoid unnecessary travel within the quarantine zones to aid containment efforts.

Cultural and Agricultural Insights

South Korea has faced multiple waves of avian influenza since 2003, with H5 subtype viruses causing significant economic losses in the poultry industry. The country’s dense poultry farming and migratory bird patterns contribute to recurrent outbreaks. Public awareness and strict government-led biosecurity measures remain essential in controlling AI spread. The Seosan incident underscores the delicate balance between agricultural productivity and infectious disease management in Korean rural communities.

Ongoing Monitoring and Future Outlook

The Animal and Plant Quarantine Agency is expected to release definitive results on the pathogenicity of the detected virus within 1 to 3 days. Meanwhile, all culling and disinfection activities are ongoing with the goal of preventing further transmission. The government continues to monitor the situation closely, emphasizing rapid response and cooperation from all stakeholders to mitigate the impact of this outbreak.