Washington State Department of Health is investigating presumed positive human cases of avian influenza in Washington. Healthcare providers should consider avian influenza in patients who present with acute respiratory illness, isolated conjunctivitis, or influenza-like illness (ILI). Assess patients for exposure to animals––especially poultry, cattle, and wildlife, or to people suspected or known to be infected.
Current situation
On Oct. 20, 2024, DOH and Benton-Franklin Health District (BFHD) reported 4 people were under investigation for avian influenza in Washington. As of Wednesday, Oct. 30, CDC has confirmed 9 cases, with additional cases pending confirmation. These are the first human cases of avian influenza identified in the state. Those who tested positive for avian influenza A(H5) work at a commercial poultry farm in Franklin County that was experiencing an outbreak of H5N1 highly pathogenic avian influenza (HPAI) in its flock.
This is an active investigation and the number of cases may change as test results come back.
DOH and BFHD are working with Washington State Department of Agriculture and CDC on the regional response to this outbreak and they:
- Provided personal protective equipment (PPE) to workers on the farm.
- Are monitoring exposed workers for symptoms.
- Are providing testing, vaccines, and treatment for symptomatic workers.
Note: There are currently no known cases in Jefferson County.
Recommendations for healthcare workers
Identify
- Consider avian influenza and other novel influenza virus infections in patients who present with:
- Symptoms of acute respiratory illness, isolated conjunctivitis, or (ILI).
- AND who were recently around poultry, cattle, or other animals that might be infected with HPAI A(H5N1),
- OR who have had exposure to someone suspected or confirmed to have avian influenza A.
- Ask these patients about:
- Exposure to:
- Poultry, like chickens, turkeys, or ducks.
- Sick or dead wildlife.
- Cattle or pigs.
- Attendance at agricultural fairs or other livestock exhibitions.
- Consumption of unpasteurized dairy products.
- Contact with animals with known or suspected avian influenza virus infection or their environments.
- For example, someone who worked at a poultry farm with known or suspected infections.
- Contact with someone suspected or confirmed to have HPAI, or is symptomatic after exposure to animals infected with HPAI.
- Exposure to:
Isolate
- Place the patient in an airborne infection isolation room (AIIR), if available.
- If an AIIR is not available, isolate the patient in a private room.
- Use standard contact and airborne precautions – including eye protection – when evaluating these patients.
- Wear recommended PPE when providing patient care and collecting samples for novel influenza testing.
Report
- Immediately report suspected cases of novel or avian influenza to Jefferson County Public Health. Call (360) 385-9400 and ask to speak to a member of the Communicable Disease (CD) team about HPAI.
Test and treat
- If you suspect avian influenza, call JCPH immediately. We will coordinate specimen collection and submission to the Washington State Public Health Lab.
- Collect:
- Nasopharyngeal swab collected in viral transport medium.
- AND conjunctival swab collected in viral transport medium if the patient presents with conjunctivitis.
- Start empiric antiviral treatment as soon as possible for patients suspected to be infected with novel influenza A viruses, including avian influenza. They have the potential to cause severe disease in humans. 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.
Educate
- If you suspect novel influenza, the patient should isolate at home away from household members and not go to work or school until it is determined they do not have avian influenza.
- Educate patients, especially those who work with livestock or poultry, about how to prevent avian influenza.
- The seasonal flu vaccine will not protect against avian influenza, but people who may be exposed to infected or possibly infected birds or other animals should get a seasonal flu vaccine. It reduces the risk of seasonal influenza, of co-infection, and possible reassortment between seasonal influenza and HPAI.
Background
HPAI H5N1 has circulated globally in wild birds for several years. This influenza A virus is deadly for poultry and many other 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 in spring of 2022. Since then, state agencies have detected infections in commercial and backyard poultry flocks. They’ve also found infections of wild mammals like skunks, raccoons, and harbor seals. HPAI H5N1 has not been found in Washington dairy cattle.
Since 2022, human cases of avian influenza A(H5N1) have been confirmed in commercial poultry workers in Colorado and dairy workers in Texas, Michigan, Colorado, and California. One case was detected in a person in Missouri with no known exposure to infected animals. CDC says the current risk to the general public is low.
Symptoms of avian influenza A virus in humans range from mild (e.g., eye infection, cold-like symptoms) to severe illness (e.g., pneumonia) resulting in death. All cases reported in the United States since 2022 have been mild. Symptoms among the cases under investigation in Washington have been mild and the people who are sick were offered oseltamivir. Investigators are looking for people who came into close contact with cases who are under investigation for chemoprophylactic treatment and symptom monitoring.
It’s critical you monitor for novel influenza A 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 are crucial to national efforts to prevent the emergence of new viruses that could have pandemic potential. Continue testing for influenza viruses and monitoring for novel influenza A virus infections year-round.
Resources for Providers
- Health Alert: Presumptive Positive Human Cases of Avian Influenza Under Investigation in Washington; Recommendations for Human Health Investigation and Response, DOH.
- 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, CDC.
- Interim Guidance on the Use of Antiviral Medications for Treatment of Human Infections with Novel Influenza A Viruses Associated with Severe Human Disease, CDC.
- 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, CDC.
- Highly Pathogenic Avian Influenza (HPAI) Infection Prevention Playbook, APIC .
- Information for Workers Exposed to H5N1 Bird Flu, CDC.
- H5 Bird Flu: Current Situation, CDC.
- Avian Influenza, DOH.
- Bird Flu in Animals and People: Causes and How It Spreads, CDC.