H5N1 highly pathogenic avian influenza (HPAI) has been confirmed by the Washington State Department of Agriculture on Oct. 18, 2024, in a backyard poultry flock in South Kitsap. There are currently no human cases associated with this flock.
On October 20, 2024, the Washington State Department of Health (DOH) reported that four poultry workers in Franklin County tested presumptive positive for avian influenza A(H5) virus.
See the “Background” section below for details.
ACTIONS REQUESTED
CONSIDER highly pathogenic avian influenza (HPAI) H5N1 and other novel influenza virus infections in the differential for patients who present with influenza-like illness (ILI) or isolated conjunctivitis and have one or more of the following risk factors:
- Exposure to cattle or pigs
- Attendance at agricultural fairs or other livestock exhibitions
- Consumption of unpasteurized (raw) dairy products
- Exposure to sick or dead wildlife
- Contact with birds or other animals with known or suspected avian influenza virus infection
TEST for novel influenza for patients with ILI or isolated conjunctivitis who have had any of the above exposures in the past ten days and have no alternative diagnosis. Contact your local health jurisdiction for guidance on specimen collection and testing.
IF AVIAN OR NOVEL INFLUENZA INFECTION IS SUSPECTED:
- Contact your local health jurisdiction, Kitsap Public Health District (KPHD), immediately to help arrange sample collection and testing at the Washington State Public Health Laboratories (WA PHL). Call KPHD at 360-728-2235 for assistance.
- Preferred respiratory specimens for influenza virus testing include a nasopharyngeal or nasal swab, or a nasal wash or aspirate. Nasal and throat swabs combined in the same specimen increases detection of influenza viruses than either specimen type alone, and conjunctival swabs should be considered for those with conjunctivitis.
- Empiric antiviral treatment should be started as soon as possible for patients suspected to be infected with novel influenza A viruses as they have the potential to cause severe disease in humans.
- Your local health jurisdiction may be able to assist you in acquiring antiviral medications. Call KPHD at 360-728-2235 if you need assistance.
- 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.
BACKGROUND
An ongoing global outbreak of highly pathogenic avian influenza (HPAI) in wild birds, with transmission to poultry and certain mammals including dairy cattle, has resulted in several confirmed cases of HPAI in humans in the United States in 2024.
The outbreak involves a strain of influenza A (H5N1) which has been circulating globally in wild birds for several years. HPAI infection has been deadly for many species of birds. 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 sporadic 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.
On October 20, 2024, DOH announced that four agricultural workers tested presumptive positive for avian influenza after working with infected poultry at a commercial farm in Franklin County 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. The investigation is active and the number of cases under investigation may change as further test results are received.
HPAI was reported in backyard poultry flocks in Kitsap County in 2022 and October of 2024.
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.
ADDITIONAL RESOURCES
- USDA’s Detections of Highly Pathogenic Avian Influenza page
- CDC’s H5 Bird Flu: Current Situation page
- CDC’s Clinical Overview of Evaluating and Managing Patients Exposed to Birds Infected with Avian Influenza A
- WSDA’s Highly Pathogenic Avian Influenza 2022/2024 page
- DOH’s Avian Influenza page
CONTACTING THE HEALTH DISTRICT
- Call: 360-728-2235 and leave a message. Includes reporting notifiable conditions 24 hours a day, 7 days a week. Leave the patient’s name, date of birth and disease.
- Fax: 360-813-1168.