Emergence of Avian Metapneumovirus in the Poultry Industry

Iowa’s poultry industry, alongside producers across the U.S., is still navigating the ever-changing landscape of widespread, highly contagious diseases. While strict biosecurity measures have been widely adopted and promoted nationwide to mitigate Highly Pathogenic Avian Influenza (HPAI)-a major concern for producers since its resurgence in early 2022-another significant threat has emerged: Avian Metapneumovirus (aMPV) or swollen head syndrome.

Although there is no threat to public health or food safety, it presents substantial challenges for the turkey industry. Research shows that while aMPV causes infection among all poultry, turkeys appear to be more susceptible to the virus.

The highly contagious virus compromises respiratory health and risks secondary infections posing a serious threat to current production and future stability of the turkey industry nationwide and particularly in Iowa, one of the top turkey producing states.


Spread and Economic Impact of aMPV

Back in March 2024, the USDA Animal and Plant Health Inspection Service (APHIS) released a statement confirming aMPV in samples from turkeys and broilers that were identified two months prior. By Spring, the virus had rapidly spread to most of the nation’s turkey producing states. The National Turkey Federation (NTF) estimates that approximately 60-80% of the commercial turkey flocks nationwide have been impacted during the outbreak.

Gretta Irwin, Executive Director at the Iowa Turkey Federation (ITF), estimates that approximately 570,000 turkeys in Iowa have been lost from aMPV, nearly double the number of turkeys lost from HPAI in 2024. To help eradicate the spread of HPAI, the USDA currently provides compensation for some losses and costs related to the positive detections on commercial operations. However, there is no compensation available for losses caused by aMPV at this time. The ITF estimates that Iowa turkey farmers have lost nearly $18 million dollars of income and is urging for policy change for Livestock Indemnity Program (LIP) funding eligibility to provide some financial relief to turkey producers.

The repercussions of aMPV have rippled through the entire poultry supply chain. From small, family-owned turkey operations to large commercial producers down to the processing plants and their employees. The implications of the virus have left some processing plants limited on supply to operate at full capacity. The ITF reports that the virus has taken around 2 million lbs. of turkey off the market every week.

Figure 1: Number of poults hatched from 2019-2024

The Iowa Turkey Federation also reports that infections in breeder hens have led to a significant decline in egg production, resulting in fewer poults being hatched (Figure 2). This reduction in hatched poults (and substantial on farm losses) has, in turn, significantly contributed to the overall decline in turkey supply.  

Irwin said, “Turkey consumption has dropped almost 2 pounds per person over the last five years, down to 14 pounds per person in 2024.  Due to High Path Avian Influenza for the past 10 years and now aMPV, turkey supply is unpredictable.   This instability has caused retailers and manufactures to remove turkey from menus, stores and further processed products.  Often chicken is used to replace turkey.  Until the US government and the turkey industry can provide a consistent supply of product, this trend is likely to continue.”

Figure 2: U.S. turkey consumption per capita 2019-2024

Moving Forward 

After nearly a year of advocating for additional tools and animal health solutions to address the aMPV challenge through meetings with congressional and regulatory leaders, efforts to assess the virus’s impact to secure additional support and a collective industry to push to import a proven effective vaccine from Europe to treat and prevent aMPV, the National Turkey Federation (NTF) applauded the USDA’s decision to authorize the importation of a commercial modified live aMPV vaccine. USDA approved the first imported live vaccine in December 2024 and announced its decision to approve two more commercial modified live aMPV vaccines in late January 2025. The rollout process of vaccines has yet to be announced but are expected to be available this spring, if not sooner.

In addition to both killed and live vaccines needed for aMPV, the ITF urges the approval of antibiotics that will help manage secondary infections.

The USDA does not report the number of birds affected as aMPV is not a reportable disease further complicating efforts to mitigate the rapid spread of the virus. Gaining control of the highly contagious disease is an ongoing and uphill joint effort. Irwin says “While this decision is a crucial step in expanding our tools to combat aMPV, our team remains dedicated to collaborating with the animal health industry and USDA to develop a domestic vaccine. At the same time, we will also continue to encourage USDA's Center for Veterinary Biologics (CVB) to evaluate additional vaccines for import.”