US: Avian influenza confirmed in backyard flock of birds in Hawaii

HONOLULU — The Hawai‘i Department of Agriculture (HDOA) today received confirmation from the U.S. Department of Agriculture National Veterinary Services Laboratories (NVSL) that highly pathogenic avian influenza (HPAI) was detected in a backyard flock of various birds in Central O‘ahu. The property involved is within the area served by the Wahiawā Wastewater Treatment Plant, where a recent detection was reported through the National Wastewater Surveillance System and is under investigation by the Hawai‘i Department of Health (DOH).

This is the first confirmed detection of the virus in Hawai‘i. The virus detected here matches the strain that has infected dairy cows and domestic poultry on the U.S. mainland.

HPAI causes severe illness with a high mortality rate among affected birds. With the confirmation of avian influenza, HDOA today issued a quarantine order on the site which requires that all birds on the property be depopulated and the premises cleaned and disinfected. While confirmatory tests were being conducted, HDOA had placed a hold order, which prevents movement of any animals from the property.

Human illness with H5N1 is uncommon and reported symptoms among humans infected in the United States have been mild. DOH is investigating potential human exposures to the sick birds and can test for avian flu in persons exposed to known infected animals to help guide prompt and appropriate treatment (if symptomatic) or prophylaxis (prevention, if asymptomatic). Antiviral treatment for avian flu in humans is available and works best when taken as soon as symptoms begin.

People in Hawai‘i are unlikely to get sick from H5N1 influenza at this time. H5N1 infection in humans on the U.S. mainland have been reported almost exclusively among workers who have close contact with infected animals. The most common symptoms of avian flu in humans are conjunctivitis and upper respiratory symptoms like sore throat and cough. Sustained human-to-human transmission has not been reported.

”The current risk of transmission to Hawai?i residents is low,” said State Epidemiologist Dr. Sarah Kemble. “but be smart if you do encounter sick or dead birds, livestock, or wild animals and avoid direct contact.”

HDOA received a report of at least 10 dead birds on the property on November 12, 2024. The dead birds tested included ducks, goose and a zebra dove. An HDOA veterinarian conducted necropsies on the dead birds and sent diagnostic samples to both the DOH State Laboratories Division and to the NVSL, which is the confirmatory laboratory for all reportable animal disease diagnostics in the U.S.

It is not known at this time how the avian influenza virus arrived in Hawai‘i, but the state is in the Pacific flyway, which is a migratory path from the continental U.S. Strict quarantine rules have been in place to prevent bird diseases from entering the state via air transport and maritime routes.

HDOA has been working with DOH and has also enlisted the veterinary staff at the University of Hawai‘i College of Tropical Agriculture and Human Resilience to assist in education and outreach to poultry operations, backyard flock owners and other animals susceptible to the virus.

Since 2015, several agencies have been conducting routine surveillance for avian influenza statewide, including HDOA, two branches of the U.S. Department of Agriculture and the U.S. Geological Survey.

Resources on avian influenza:

HDOA, Animal Disease Control: https://hdoa.hawaii.gov/ai/ldc/avian-influenza-information/
DOH avian influenza information: https://health.hawaii.gov/docd/disease_listing/avian-influenza/
Centers for Disease Control and Prevention: https://www.cdc.gov/bird-flu/index.html
U.S. Department of Agriculture: https://www.aphis.usda.gov/livestock-poultry-disease/avian/avian-influenza