Avian Flu Diary: Hawaii: State Agencies Respond to 3rd Possible Case of HPAI H5 (Kauaʻi)

Hawaii lies beneath the West Pacific Flyway

#18,986

Separated as it is by vast ocean distances - 2,400 miles to the U.S., 4,000 miles to Japan - Hawaii is considered the world's most isolated populated place on earth.

And not surprisingly - until just over a year ago - the state of Hawaii had never reported H5N1 in wild or domesticated birds.

All that changed in November of 2024 after the virus was first detected in wastewater samples on Oahu, and at least two outbreaks in captive and/or wild birds the following week.

A month later, another treatment plant on the island of Hilo reported the virus.

This year, the first reported case came in mid-October (see Hawaii: DOH, DAB, DLNR Investigate Possible Avian Flu Case in Waterfowl), followed a month later by Hawaii: State Agencies Respond to 2nd Confirmed Case of HPAI H5 (Maui).

Yesterday the State of Hawaii announced their 3rd presumptive positive HPAI H5 case of this fall (see below) - this time affecting a 4th Hawaiian island (Kauaʻi).

What was once unheard of has now become increasingly common now that the HPAI H5 virus has better adapted to seabirds (see 2022's Unprecedented `Order Shift' In Wild Bird H5N1 Positives), with many species; including gannets, gulls, guillemots and great skua now hosting the virus.

The behavioral shift has not gone unnoticed by Oceania (Australia/NZ) which have been on HPAI watch for several years (see Australia: Confirmation of H5 Bird Flu on Sub-Antarctic Heard Island).

First the announcement from the Hawaiian Department of Land and Natural Resources, after which I'll return with a bit more.

12/11/25 – STATE AGENCIES RESPOND TO THIRD POSSIBLE CASE OF HIGHLY PATHOGENIC AVIAN INFLUENZA IN HAWAIʻI
Posted on Dec 11, 2025 in Forestry & Wildlife, Main, News Releases, slider
HONOLULU – Three state agencies remain on alert after a third presumptive case of avian influenza was found in a wild bird — this time in an endangered native duck on Kauaʻi. Preliminary testing performed by the Hawaiʻi State Laboratory showed the bird was infected with an influenza A virus, though confirmation and subtype identification (e.g., H5N1) are pending further analysis by the National Veterinary Services Laboratories (NVSL).
A Koloa Maoli (Hawaiian duck) was found sick on November 26 at the U.S. Fish and Wildlife Service’s Hanalei National Wildlife Refuge in Hanalei, Kauaʻi. The bird died within 24 hours.
H5N1 is a highly infectious and often deadly subtype of influenza A that mainly affects birds. Human infections are rare but can occur with close contact. Hawaiʻi’s first detection of H5N1 occurred in November 2024 in a backyard flock on Oʻahu, followed by a hybrid duck found on Oʻahu’s North Shore. This year, two additional cases have been confirmed in migratory Koloa Māpu ducks—one on Oʻahu and one on Maui. This Kauaʻi detection is the first potential case in a native bird, likely introduced through infected migratory waterfowl.
The Hawaiʻi Department of Health (DOH), Department of Agriculture & Biosecurity (DAB), and Department of Land and Natural Resources (DLNR) continue coordinated monitoring of public health reports, poultry operations and wild bird populations for any signs of virus spread.
With migratory bird season underway, more birds traveling through the islands may carry avian diseases and it is recommended that the public avoid touching or handling wild birds, especially waterfowl or shorebirds.
If you encounter sick or dead birds, such as waterfowl:
Avoid touching or handling wild birds, especially waterfowl or shorebirds.
If capturing a dead or sick bird is necessary, wear gloves, minimize contact and follow biosafety protocols.
To report multiple or unusual illnesses in poultry, livestock or other wild birds or animals, contact DAB’s Animal Industry Division at 808-483-7100, Monday through Friday from 7:45 a.m. to 4:30 p.m., or 808-837-8092 during non-business hours and holidays. Send email to DABIC@hawaii.gov
About H5N1/Avian Influenza:
H5N1 is an avian influenza virus that mainly affects birds; human infections are uncommon but can happen following close contact with infected birds.
The public risk in Hawaiʻi is currently low, so the DOH does not recommend restricting outdoor activities.
Routine influenza vaccines in humans do not protect against H5N1; the best prevention is avoiding contact with sick or dead birds.
For more information, visit:
DOH: https://health.hawaii.gov/docd/disease_listing/avian-influenza/
DAB: https://dab.hawaii.gov/ai/ldc/avian-influenza-information/

This fall we've seen unprecedented numbers of avian flu reports across North America and much of Europe - particularly in wild birds - but also affecting commercial and backyard flocks.

Credit ECDC/EFSA Avian influenza overview Sep–Nov 2025

After two less impactful years (see chart above), avian flu has reinvented itself and is back with a vengeance. While it could fizzle again, right now there appears to be an immense amount of the virus circulating in wild birds, increasings the risks of spillovers into poultry, mammalian wildlife, and even humans.

Last July we looked at the results of a survey of stakeholders (backyard poultry owners, animal rescue, etc.) on their knowledge of HPAI (see Hawaii: Findings From DOH Bird Flu Survey For Backyard Flock Bird Owners And Bird Rescuers), which found sizeable knowledge gaps.

Two months ago, in UF/IFAS Extension: What Backyard Flock Owners Need to Know about Bird Flu (Influenza H5N1) we looked at some common-sense steps people who raise birds can take to reduce the risk of infection.

Admittedly, trying to predict what HPAI does next is a mug's game, but if there was ever a time to be extra diligent in avoiding exposure to wild birds, and for flock owners to increase their biosecurity, it is probably now.

For some official advice from the ECDC/EFSA, you may wish to revisit: