Highly Pathogenic Avian Influenza A (H5N1) Response

​Highly Pathogenic Avian Influenza (HPAI) viruses can spread from wild birds to domestic poultry and other avian and animal species. HPAI viruses are highly contagious and frequently cause fatal disease primarily affecting poultry. They may also be referred to as bird or avian flu. 

2024 HPAI H5N1 Outbreak (Dairy Cows) 

Since late March 2024, the US Department of Agriculture (USDA), US Centers for Disease Control and Prevention (CDC), and US Food and Drug Administration (FDA), and state veterinary and public health officials have been investigating outbreaks of influenza A (H5N1) in dairy cows and related exposures.

APHL is coordinating with these federal partners and public health laboratories to mitigate the impact of HPAI on both animal and public health. Public health laboratories in all 50 states are equipped for detecting the causative agent in this outbreak; influenza A (H5N1) viruses.

Situational update (as of August 12):

• Current areas of impact: humans, animals (including wild birds and domestic poultry; livestock, particularly dairy milking cattle; other domestic and wild mammals) and food products (particularly raw milk and products made from raw milk from infected cows).
  

• Updated recommendations from CDC and USDA for minimizing risk of Influenza transmission at livestock exhibitions.
  

• CDC H5N1 Technical Reports (for scientific audiences)
  

• Visit the USDA and CDC HPAI pages for case numbers and spread.
  

HPAI Testing and Surveillance Information

Federal Partners

From CDC's June 5, 2024 H5N1 Technical Report: CDC, along with state and local public health partners, continues to monitor people in the US who have been exposed to infected birds, poultry, dairy cattle or other animals for 10 days after their last exposure. To date, more than 9,000 people in 52 jurisdictions have been monitored since 2022.

Public Health Laboratories

Public health laboratories in all 50 states are equipped for detecting influenza A (H5N1) viruses, and 26 APHL member laboratories test milk under the Pasteurized Milk Ordinance.

Public health laboratories are likely to see an increase in summer influenza testing this season, particularly in areas of the country with active outbreaks. The following types of laboratories or laboratory departments should prepare for surge testing:  

HPAI Response Resources

Laboratory Testing Resources

• APHL: HPAI Frequently Asked Questions (FAQ) and Resources for Public Health Laboratories
  

• APHL & ASM: Laboratory Testing of HPAI A(H5N1) FAQ For Clinical Laboratories

• APHL: Risk Assessment Guide for Testing Raw Milk Samples That May Contain Highly Pathogenic Avian Influenza
  

• APHL: Biosafety Considerations for Milk and Dairy Testing

• FDA: Interim HPAI Virus Biosafety Recommendations and Resources for Industry Laboratories and State Dairy & Dairy Product Laboratories

• CDC & Michigan: Highly Pathogenic Avian Influenza A(H5) Virus Testing at MDHHS BOL and CDC
  

Influenza Surveillance and Public Health Action Resources

• APHL: National Influenza Surveillance Guidance
  

• CDC: Public Health Strategies for Enhanced Summer 2024 Influenza Surveillance
  

• CDC: HPAI (H5N1) Interim Recommendations for Prevention, Monitoring and Public Health Interventions 
  

• CDC: Public Health Science Agenda for Highly Pathogenic Avian Influenza A (H5N1)
  

Additional Resources 

• Seasonal Influenza Surveillance Guidance
• HPAI Call Summaries
• HPAI Email Updates