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April 19, 2024

Maintain vigilance for detection, management, and reporting of highly pathogenic Avian Influenza A (H5N1) virus infections

Actions requested

  • Be aware of an ongoing outbreak of highly pathogenic avian influenza (HPAI) A(H5N1) viruses among wild birds, poultry, and now among cattle in the United States, with one recently confirmed human infection in Texas following exposure to infected dairy cattle.
  • Consider HPAI A (H5N1) virus infection in people showing signs or symptoms of influenza or conjunctivitis and who have recently been around birds, cattle, or other animals that might be infected with HPAI A(H5N1) viruses.
    • Symptoms may include but are not limited to cough, sore throat, eye redness (conjunctivitis), fever, rhinorrhea, fatigue, myalgia, arthralgia, headache, shortness of breath or difficulty breathing, altered mental status, nausea, vomiting, diarrhea, and seizures.
  • Isolate and place a facemask on patients with suspected avian influenza A(H5N1) and implement infection control measures immediately.
    • Place in a single-patient airborne infection isolation room or if not available, a single room with the door closed.
    • Implement standard, contact, and airborne precautions, including appropriate personal protective equipment for healthcare workers.
  • Begin empiric antiviral treatment as soon as possible in patients with suspected avian influenza A(H5N1), regardless of time since onset of symptoms.
    • Antiviral treatment should not be delayed while waiting for results of laboratory tests.
  • Collect respiratory specimens from suspected cases to test for influenza A(H5N1) virus by real-time RT-PCR at the state public health laboratory.
    • In all suspected cases, collect two upper respiratory specimens, where one of the specimens is a nasopharyngeal swab. In suspected cases with conjunctivitis as a symptom, collect a third (conjunctival) swab.
    • Use swabs with a synthetic tip and an aluminum or plastic shaft to collect specimens and place in collection vials with 1-3ml of sterile viral transport medium. Store at ≤-20°C and ship on dry ice.
  • Advise patients with suspected avian influenza A(H5N1) virus infection to isolate at home and away from household members and to not go to work or school until avian influenza A(H5N1) is ruled out.
  • Immediately report suspected or confirmed cases of influenza A(H5N1) to Public Health at (206) 296-4774.

Background

An outbreak of highly pathogenic avian influenza (HPAI) A(H5N1) in dairy cows in the United States was first reported by the U.S. Department of Agriculture (USDA) on March 25, 2024. Infections in dairy cows have now been reported in several U.S. states. CDC confirmed one human HPAI A(H5N1) virus infection in Texas following exposure to infected dairy cattle. The patient reported conjunctivitis with no other symptoms, received antiviral treatment, and has recovered. CDC analysis found that the virus sequence from the patient specimen was very similar to those from infected cattle, wild birds, and poultry. There were no markers in the virus sequence indicating resistance to antiviral drugs, and the virus is very closely related to existing candidate vaccine viruses that are already available to manufacturers and could be used to make vaccine if needed. No known person-to-person spread has been reported with the contemporary A(H5N1) viruses that are currently spreading globally.

While the overall risk of HPAI A(H5N1) virus to the U.S. public remains low at this time, people with job-related or recreational exposures to infected birds, cattle, or other potentially impacted domestic or wild animals are at higher risk and should take precautions outlined in CDC recommendations for any person working with or exposed to animals such as poultry and livestock farmers and workers, backyard flock owners, veterinarians, and veterinary staff, and responders.
Healthcare providers should also reinforce with their patients the general recommendation for the public to avoid consumption of unpasteurized or raw milk.

Resources

This health advisory is also available in PDF format (273 KB)

For Healthcare Providers

For General Public

For Farmers, Workers, and Livestock and Poultry Owners

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