This is a Provider Alert from the Washington Department of Health (DOH) regarding presumed human cases of avian influenza under investigation in Washington.
Clinicians in Washington should consider avian influenza infection in patients who present with acute respiratory illness, isolated conjunctivitis, or influenza-like illness (ILI), and to assess patients for exposures to animals (poultry, cattle, wildlife, or other animals) or people suspected or known to be infected with avian influenza.
Current Situation
On October 20, 2024, Washington State Department of Health and Benton-Franklin Health District reported that four people are under investigation for avian influenza infection in the state. These cases are the first potential human cases of avian influenza identified in Washington. Four workers tested presumptive positive for avian influenza A(H5) after working at a commercial poultry farm in Franklin County which was experiencing an outbreak of H5N1 highly pathogenic avian influenza (HPAI) in their flock.
The presumptive positive samples have been forwarded to the Centers for Disease Control and Prevention (CDC) for confirmatory testing. This is an active investigation and the number of cases under investigation may change as further test results are received.
DOH and BFHD are working with the Washington State Department of Agriculture and the CDC on the regional response to this outbreak. DOH and BFHD have provided personal protective equipment to workers on the farm, are monitoring exposed workers for symptoms of avian influenza, and are providing testing, influenza vaccines and treatment for symptomatic workers.
Actions Requested
- Immediately report any suspected cases of novel or avian influenza in a person to your Local Public Health Jurisdiction (LHJ). Novel influenza is a notifiable condition in Washington state.
- Clinicians should consider avian influenza and other novel influenza virus infections in patients who present with the following:
- Symptoms of acute respiratory illness, isolated conjunctivitis, or influenza-like illness (ILI), AND
- Recent close contact with animals known or suspected to have avian influenza A virus infection, OR
- Exposure to a suspected, probable or confirmed human case of HPAI H5N1, including symptomatic persons who have been exposed to avian influenza A in animals but have not been tested or diagnosed.
- Specifically, ask patients presenting for care with the clinical syndromes above about:
- Exposure to poultry (e.g., chickens, turkeys, ducks)
- Exposure to sick or dead wildlife
- Exposure to cattle or pigs
- Attendance at agricultural fairs or other livestock exhibitions
- Consumption of unpasteurized dairy products
- Contact with other animals with known or suspected avian influenza virus infection or their environments (e.g., worked at a poultry farm with known or suspected infections)
- Contact with another person suspected or confirmed to be infected with HPAI, or symptomatic after exposure to animals infected with HPAI
- Clinicians should consider testing for novel influenza for patients with acute respiratory illness, isolated conjunctivitis, or influenza-like illness (ILI) who endorse any of the above exposures in the past ten days and have no alternative diagnosis.
- If novel influenza infection, including avian influenza, is suspected, contact your local health jurisdiction immediately to help arrange sample collection and testing at the Washington State Public Health Laboratories (WA PHL). Your local health jurisdiction can provide guidance on collecting the below samples:
- A nasopharyngeal swab collected in viral transport medium for testing at WA PHL
- A conjunctival swab collected in viral transport medium for testing at WA PHL for patients presenting with conjunctivitis
- Standard, contact and airborne precautions, including the use of eye protection, are recommended when evaluating patients for infection with avian influenza.
- If an airborne infection isolation room (AIIR) is not available, isolate the patient in a private
- Healthcare personnel should wear recommended personal protective equipment (PPE) when providing patient care and when collecting samples for novel influenza testing.
- For more information on recommended infection prevention and control measures, please visit Infection Control Within Healthcare Settings for Patients with Novel Influenza A Viruses.
- Empiric antiviral treatment should be started as soon as possible for patients suspected to be infected with novel influenza A viruses, including avian influenza, as they have the potential to cause severe disease in humans. For more information, see the CDC’s interim guidance on the use of antiviral medications for treatment of human infections with novel influenza A viruses associated with severe human disease.
- If novel influenza is suspected, the patient should isolate at home away from their household members and not go to work or school until it is determined they do not have avian influenza A virus infection.
Background
Highly pathogenic avian influenza (HPAI) H5N1 has been circulating globally in wild birds for several years; this influenza A virus is deadly for poultry and many species of birds and has caused sporadic infections and outbreaks in wild mammals and dairy cattle. Cases of HPAI in wild birds and poultry.
were first identified in Washington state in the spring of 2022. Since 2022, WA state agencies have detected infections in commercial and backyard poultry flocks, as well as infections of wild mammals such as skunks, raccoons, and harbor seals. There have been no detections of HPAI H5N1 in dairy cattle in Washington state.
Since the start of the outbreak in 2022, human cases of avian influenza A(H5N1) infection have been confirmed in commercial poultry workers in Colorado and among dairy workers in Texas, Michigan, Colorado, and California. One case of avian influenza A(H5N1) infection has been detected in a person in Missouri with no known exposure to infected animals. According to the U.S. Centers for Disease Control and Prevention, the current risk to the general public is low.
Symptoms of avian influenza A virus infections in humans have ranged from mild (e.g., eye infection, cold-like symptoms) to severe illness (e.g., pneumonia) resulting in death, though all cases reported in the U.S. since 2022 have been mild. Symptoms among the cases under investigation in Washington have been mild and the affected individuals have been offered oseltamivir.
Investigations are ongoing to identify close contacts of cases under investigation for chemoprophylactic treatment and symptom monitoring.
As the multistate outbreak of avian influenza A (H5N1) in poultry, dairy cattle, and other animals continues, monitoring for novel influenza A virus infections in humans is critical to identify transmission of these viruses between animals and people. Rapid detection of, and treatment for, novel influenza A viruses and efforts to reduce transmission to other people remain important components of national efforts to prevent the emergence of new viruses that could have pandemic potential. To accomplish this, testing for influenza viruses and monitoring for novel influenza A virus infections should continue year-round.
Resources for Providers
- H5 Bird Flu: Current Situation | Bird Flu | CDC
- Interim Guidance on Specimen Collection and Testing for Patients with Suspected Infection with Novel Influenza A Viruses Associated with Severe Disease or with the Potential to Cause Severe Disease in Humans | Bird Flu | CDC
- APIC Highly Pathogenic Avian Influenza (HPAI) Infection Prevention Playbook
- Interim Guidance for Infection Control Within Healthcare Settings When Caring for Confirmed Cases, Probable Cases, and Cases Under Investigation for Infection with Novel Influenza A Viruses Associated with Severe Disease | Bird Flu | CDC
- Avian Influenza | Washington State Department of Health
- Bird Flu in Animals and People: Causes and How It Spreads | Bird Flu | CDC
To report suspected cases, or for any other questions, please contact your Local Health Jurisdiction.
