Highly Pathogenic Avian Influenza (HPAI)

Highly Pathogenic Avian Influenza (HPAI) Detected in California

Highly pathogenic avian influenza (HPAI) is spreading throughout the U.S. and was first confirmed by the California Department of Fish and Wildlife (CDFW) in California’s Colusa and Glenn counties on July 13, 2022. Since then, there have been additional confirmed cases in California, including in Sonoma and Sacramento counties. The virus is expected to reach San Diego County any day and as a result, San Diego Humane Society is implementing biosecurity processes and procedures to provide the most compassionate care to animals in need while mitigating the spread of disease.

Avian influenza (also known as “bird flu”) occurs mainly in birds and is highly contagious. It is caused by viruses that occur naturally among wild birds. The highly pathogenic (HPAI) variants are potentially deadly to many species of domestic and wild birds, and in some cases mammals (e.g., cats). According to data compiled by the USDA, avian influenza H5N1 has been detected in at least 1,825 individual wild birds in 42 states and the District of Columbia since January 2022.

Clinical signs of HPAI can vary. In general, signs develop within 3-21 days after exposure and may include:

• Sudden death and increased mortality in a flock
• Neurological signs (tremors of head and neck, inability to stand, paralysis)
• Low appetite, lethargy and diarrhea
• Difficulty breathing, sneezing, nasal discharge and coughing
• Swelling of the head, eyelids, neck and hocks
• Purple discoloration of legs

How does it spread?
The virus is spread among birds through direct contact with oral or respiratory secretions, by a fecal-oral transmission, or by indirect contact through contaminated objects and surfaces. Avian influenza viruses naturally circulate in waterbirds, including waterfowl and shorebirds, with or without clinical signs. Avian predators or scavengers, including eagles, raptors, crows, ravens, gulls or vultures, may be exposed when feeding on infected waterbirds, especially during mortality events (e.g., avian cholera, avian botulism). In poultry, HPAI is highly contagious and causes significant mortality. Birds raised in captivity, such as other gallinaceous birds (turkeys, pheasants, grouse, quail) and waterfowl (ducks, geese, swans), may also be at high risk of acquiring and transmitting the virus. Avian influenza viruses are shed in bodily fluids such as saliva, nasal secretions and feces. They can be transmitted directly from an infected bird or indirectly through people or objects contaminated with virus particles (e.g., animal crates, bedding, perches, feathers, food, water, clothing, footwear, vehicles).

The virus may stay present in water for some time. The disease’s severity impacts species of birds differently. HPAI is especially deadly for gallinaceous birds (such as domestic poultry and game birds). Tragically, these birds often suffer 90-100% mortality. Other birds, such as waterfowl, can be infected with HPAI without showing any symptoms.

Practicing biosecurity is the most effective way to keep domestic poultry and pet birds healthy. Please visit the California Department of Food and Agriculture (CDFA) and USDA websites for biosecurity information. Sick and dead poultry may be reported to the CDFA hotline at 866-922-2473. The public may report dead wild birds using CDFW’s mortality reporting form.

What other animals can be affected?
HPAI strains have occasionally been reported to infect some mammal species, including: pigs, cats, dogs, foxes, martens, civets, tigers and humans. Red foxes have been noted to be particularly susceptible.

Can it affect humans?
Currently, the Center for Disease Control considers the transmission risk of avian influenza to people to be low. The current strain, HPAI H5N1 influenza, can infect humans only under rare circumstances (if they have very close contact with infected birds). There is no human immunity to HPAI and no vaccine available for humans. For protective actions for human health, visit the CDC website.

What procedures are we implementing as a result of HPAI?
HPAI is a serious concern, and as a result, strict biosecurity and cleaning measures are essential to protect the wellbeing of animals throughout San Diego County. Following the guidance of CDFW, USDA and CDFA, the best way for us to remain open without spreading the virus to other animals is to restrict susceptible avian species from entering our buildings. This includes both domestic and wild birds.

As you can imagine, this is an incredibly difficult decision for us. Our goal is to help as many animals as possible, and in this case, that means not allowing certain avian species to enter our care. We are advising people to renest and reunite youngsters with their parents to prevent uninjured orphans from coming into our care. If an animal is showing signs of illness or injury, we do not want them to suffer and we will perform humane euthanasia at arrival.

• We will only accept intakes of wild birds at the Ramona Wildlife Center and Pilar & Chuck Bahde Wildlife Center. 
• The after-hours/overnight drop off room at the Bahde Wildlife Center will be closed indefinitely. 
• Project Wildlife will not take in any patients from outside San Diego County. 
• Birds who are young and healthy, and showing no signs of injury or illness, will be considered for release back into the wild. We encourage the public to leave healthy youngsters alone rather than bring them to San Diego Humane Society. 
• Injured, ill or orphaned birds susceptible to HPAI may be humanely euthanized on intake and sent for testing. 
• To protect our Project Wildlife ambassador birds, we have removed them from our campuses and placed them temporarily in approved staff homes. 
• We will be focusing on getting our companion birds out of shelter care as soon as possible to protect them from infection. 

Where can people learn more about HPAI?
Official updates and information about avian flu can be found through the following sources:

• An informational flyer addressing frequently asked questions is available on CDFW’s website.
• National Wildlife Health Center: Distribution of HPAI in North America, 2021/2022
• USDA Animal and Plant Health Inspection Service: 2022 Detections of HPAI
• International Bird Rescue
• San Diego Humane Society's Highly Pathogenic Avian Influenza (HPAI) Disease Q&A

Updated Aug. 8, 2022

Published: July 15, 2022