Avian Influenza

What to know

H5N1 bird flu virus has been circulating worldwide and has been causing outbreaks in poultry and dairy cows in the U.S. A limited number of human cases have occurred in 2024 following exposure to infected animals.
The Hawaii Department of Agriculture (HDOA) received confirmation from the U.S. Department of Agriculture National Veterinary Services Laboratories (NVSL) on November 15, 2024 that highly pathogenic avian influenza (HPAI) was detected in a backyard flock of various birds in Central Oahu.
The current risk to the general public in Hawaii remains low.
Residents are encouraged to report sick or dead birds, especially when multiple birds are affected to Hawaii Department of Agriculture (808-483-7102 during Monday to Friday from 7:45AM to 4:30PM, or 808-837-8092 during non-business hours and holidays).
Hawaii residents who recently visited or worked on a farm in another state with known or suspected H5N1 animal infections should contact the Hawaii Department of Health’s Disease Reporting Line (808-586-4586) for a telephone risk assessment.

About This Disease

Avian influenza (bird flu) viruses occur naturally in wild birds. Avian influenza A viruses have been isolated from more than 100 different species of wild birds around the world, including ducks, geese, terns, plovers, and sandpipers. These viruses are very contagious among birds and have the potential to cause severe illness among poultry, other animal species, and even among humans exposed to the virus. For more general information about influenza A viruses: Avian Influenza Type A Viruses | Bird Flu | CDC

Current Events

H5N1 influenza A virus in the United States

The H5N1 influenza A virus has been circulating globally since it was first identified in birds in 1996. Since 2021, the H5N1 virus has been widely detected among wild birds, poultry farms, and backyard poultry flocks in the United States. In 2024, H5N1 was detected in dairy cows for the first time in the continental United States with spread to dairy cow herds in multiple states. In addition, fatal H5N1 infections among cats have been detected on affected farms. For the latest information on avian influenza in livestock, visit the USDA website.

Pasteurized milk and dairy products remain safe. Gold-standard laboratory investigations by the U.S. Food and Drug Administration have shown pasteurization to fully inactivate the H5N1 virus in milk. Therefore, the ongoing multi-state outbreak of H5N1 in dairy cows does not pose a health risk to consumers.

The first reported human infection with the H5N1 influenza A virus in the U.S. was detected in Colorado on April 28, 2022. The individual was directly exposed to infected poultry and reported fatigue as the only symptom. They were treated and since recovered.

Since April 2024, additional human H5N1 infections have been reported in the continental U.S. predominantly among workers with exposure to dairy cows or poultry with suspected or confirmed H5N1 infection. All cases have been clinically mild with symptoms of conjunctivitis or respiratory symptoms. All cases have recovered. There has been no definitive evidence of human-to-human transmission of the H5N1 virus in the U.S. Therefore, the main risk for H5N1 exposure at this time is close contact with animals infected with the virus. For current information regarding human H5N1 influenza A infections, including CDC’s latest analysis and human health risk assessment, please click here.

H5N1 influenza A virus in Hawaii 2024

HDOA received confirmation from the U.S. Department of Agriculture National Veterinary Services Laboratories (NVSL) that HPAI was detected in a backyard flock of various birds in Central O’ahu on November 15, 2024. The property involved is located within the service area of the Wahiawā Wastewater Treatment Plant, where a recent detection was reported via the National Wastewater Surveillance System. This is the first confirmed detection of the virus in Hawai‘i. The virus detected is clade 2.3.4.4b, similar to the strain that has infected wild birds, domestic poultry, and dairy cows on the U.S. mainland. Genotype results are pending.

Upon further investigation, HDOH and HDOA have identified a potential exposure to attendees of the Mililani Pet Fair held on November 02, 2024. Although some birds from the infected flock were present at the event, the first signs of infection in the flock did not appear until several days afterward. Since the birds were not showing symptoms at the time of the fair, the risk of them transmitting H5N1 to humans is considered low.

Why is this a public health concern in Hawaii?

Influenza viruses undergo genetic reassortment, or change, as they spread between different animal species and humans. There is a risk that the H5N1 or other avian influenza viruses might change to spread more easily between humans, potentially leading to a pandemic. Therefore, practicing avian influenza prevention practices, monitoring for animal and human infections, and detecting any person-to-person spread early is extremely important for public health.

Monitoring for Avian Influenza in Hawaii

HDOH, in partnership with the Department of Agriculture and the Center for Disease Control and Prevention (CDC), is reinforcing long-standing efforts to detect avian influenza disease in birds, cattle, and humans in Hawaii. This includes monitoring human influenza infections detected in the laboratory, as well as in wastewater, monitoring of ED visits for influenza as tracked on the Hawaii Respiratory Disease Activity Summary dashboard, participation in the National Poultry Improvement Plan with routine sampling of chickens at the state’s largest poultry farm, USGS (United States Geological Survey) collection and testing of wild bird specimens and testing of any lactating cows being brought into the state.

Signs and Symptoms

The risk of avian influenza in Hawaii remains low for the general public. Human avian influenza symptoms are similar to those of seasonal flu. Symptoms may vary from mild to severe, and may begin with flu-like symptoms, including fever, cough, and/or sore throat. Recent human H5N1 influenza infections reported in the U.S. have been mild and included conjunctivitis.

Main symptoms (only some may be present):

Fever
Cough
Sore throat
Conjunctivitis (“pink eye”)

Secondary symptoms:

Runny nose
Fatigue
Headache
Muscle ache
Diarrhea
Vomiting
Breathing difficulties

Risk in Hawaii

Although the risk of avian influenza to the general public in Hawaii from bird flu viruses is low, the following may place individuals at increased risk for H5N1 influenza virus infection:

Close contact with sick or dead animals, including wild birds, poultry, other domesticated birds, and other wild or domesticated animals.
Handling the feces, bedding (litter), or materials that have been touched by, or close to, birds or other animals on a farm with suspected or confirmed H5N1 influenza virus infection.
Consuming raw, unpasteurized, milk or dairy products

How Infected Backyard Poultry Could Spread Bird Flu to People

Prevention

General guidance

In addition to the Hawaii Department of Health’s respiratory guidance, the following measures can reduce the risk of being infected with avian influenza.

Do not touch sick or dead birds. Residents are encouraged to report sick or dead birds, especially when multiple or unusual. Please contact Animal Industry Division at Hawaii Department of Agriculture at 808-483-7102 during Monday to Friday from 7:45AM to 4:30PM, or 808-837-8092 during non-business hours and holidays.
Do not drink raw milk. Pasteurization kills H5N1 virus, and pasteurized milk is safe to drink.
When in direct or close contact (within six feet) of sick or dead animals with suspected or confirmed avian influenza, or the feces, litter, raw milk, or contaminated materials, wear Appropriate CDC-recommended personal protective equipment (PPE). Further detail is available here.
If you become sick due to direct contact with sick or dead animals with suspected or confirmed avian influenza, isolate from family and stay home until you are proven to not have bird flu virus infection.
Influenza antiviral chemoprophylaxis can be prescribed by health care providers to persons exposed to avian influenza. Further information can be found here.

Healthy backyard poultry practices

Keeping backyard poultry has become more popular in Hawaii as communities work to produce food locally. Adopting healthy, sustainable flock ownership practices is important to prevent illness among people and birds. The Hawaii Department of Health encourages backyard poultry owners, or those contemplating poultry ownership, to fully review CDC guidance on healthy backyard poultry practices.

Backyard poultry owners, and community members regularly surrounded by feral chickens, are encouraged to become familiar with these signs of sick poultry:

Eat or drink less than normal
Have ruffled feathers
Have runny diarrhea
Have discharge from the eyes or nose or difficulty breathing
Produce fewer eggs than normal
Produce discolored, irregular, or misshapen eggs
Die unexpectedly of no apparent cause

Contact your veterinarian or the Hawaii Department of Agriculture at 808-483-7102 during Monday to Friday from 7:45AM to 4:30PM, or 808-837-8092 during non-business hours and holidays if you notice these signs.

Poultry and livestock farmers and workers

Commercial poultry and livestock farms can implement USDA and Hawaii Department of Agriculture biosecurity guidance and regulations to reduce the risk of avian influenza importation. In the event of a suspected or confirmed animal avian influenza infection on a farm, the Hawaii Department of Health recommends rapid implementation of CDC guidance to reduce the risk of human infections.

Hunters

Do not harvest or handle wild birds that are obviously sick or found dead.
Always wear disposable gloves when handling or cleaning game. Wash your hands with soap and water immediately afterward. If soap and water are not available, use an alcohol-based hand sanitizer.
Dress game birds while in the field whenever possible. If you can’t dress birds in the field, clean them in a location away from poultry and other birds.
Keep a separate pair of shoes to wear only in your game cleaning area. If this is not possible, wear rubber footwear and clean and disinfect your shoes before entering or leaving the area.
Use dedicated tools for cleaning game, whether in the field or at home. Do not use these tools around poultry or pet birds.
Double bag the offal and feathers. Tie the inner bag, take off your gloves, and leave them in the outer bag before tying it closed. Then wash your hands or use hand sanitizer.
Place the bag in a trash can that poultry and pet birds cannot access. Make sure the trash can is covered, and children, pets, or other animals can’t get into it.
Wash all tools and work surfaces with soap and water. Then, disinfect them using a freshly mixed chlorine solution consisting of 1/3 cup of household bleach per 1 gallon of water.

Handout: Hunters-Protect Your Poultry and Pet Birds from Avian Influenza (usda.gov)

Recent News

DOH Investigating Human Contacts to Infected H5N1 Flocks – No Humans in Hawaiʻi Tested Positive for Avian Influenza

DOH Notifies Public of Potential Exposure to Avian Influenza at Mililani Pet Fair Held Nov. 2

Avian Influenza Confirmed in Backyard Flock of Birds

H5 Avian Flu Detected at Wastewater Sampling Site on Oʻahu, DOH Closely Monitoring Situation

Additional Resources

Information for Clinicians

An overview of CDC’s recommendations for patient evaluation, treatment and testing can be found here. On July 19, 2024, CDC issued an Emergency Use Instructions for oseltamivir usage towards pandemic influenza A viruses and novel influenza A viruses with pandemic potential.

Disease Reporting

Highly pathogenic avian influenza (HPAI) is an URGENT CATEGORY NOTIFIABLE CONDITION. Those who were in direct contact to sick or dead animals infected with avian influenza or healthcare providers with patient(s) suspected of HPAI infection must report to the Hawaii State Department of Health by telephone as soon as a provisional diagnosis is established. Do not wait for laboratory confirmation.

Disease Reporting Lines
Oahu (Disease Reporting Line)	808-586-4586
Maui District Health Office	808-984-8213
Kauai District Health Office	808-241-3563
Big Island District Health Office (Hilo)	808-933-0912
Big Island District Health Office (Kona)	808-322-4877
After hours on Oahu	808-600-3625
After hours on neighbor islands	808-360-2575 (toll free)

Last reviewed November 2024