Frequent Questions—Washington Seal Stranding Event
NOAA Fisheries and partners from Washington Department of Fish and Wildlife and Port Townsend Marine Science Center have documented the first cases of avian influenza in seals stranding in Washington state.
What was announced?
A small number of harbor seals have tested positive for highly pathogenic avian inﬂuenza in Washington state at Fort Flagler State Park. An outbreak of avian influenza, also known as bird flu, has been impacting wild birds since early July 2023 in this area. Washington Department of Fish and Wildlife staff are monitoring and responding to the situation. They have removed more than 1,700 dead Caspian terns and gulls from Rat Island and adjacent shores of Marrowstone Island near Fort Flagler State Park.
What are the ﬁndings in stranded seals?
Testing of samples has found some harbor seals positive for highly pathogenic avian inﬂuenza H5N1. It is a zoonotic disease that has the potential to spread between animals and people (and their pets). However the health risk posed by the current avian ﬂu to the general public is low. Full or partial necropsy examinations were conducted on several seals. Based upon recent research on seals in Maine with HPAI infections, the virus is most likely transmitted from wild birds to seals. It is unlikely that multiple seals acquired the viruses through predation or scavenging of an infected source (such as an infected bird) at this scale, as birds are not a typical food source for harbor seals.
What can I do to help the investigation?
The most important step members of the public can take to assist investigators is to immediately report any sightings of seals in distress or dead stranded seals. For the West Coast (i.e., off California, Oregon, and Washington) call the NOAA Fisheries West Coast Region Stranding Hotline: (866) 767-6114. Do not approach or touch the seal, and keep your pets far away.
Have other mammals or animals been aﬀected by this die-oﬀ event?
Yes, there is an ongoing highly pathogenic avian inﬂuenza H5N1 event. It began in 2021 in domestic birds and wild birds and some species of terrestrial mammals across the United States (e.g., red fox, striped skunk, opossum, raccoon, bobcat, American mink, coyote, ﬁsher cat, bear, river otter). More information can be found at USDA, NWHC, CDC, Washington Department of Health, and Washington Department of Fish and Wildlife.
Is this inﬂuenza outbreak in seals associated with the larger avian fluoutbreak in North America?
The current outbreak of highly pathogenic avian inﬂuenza in North America was ﬁrst detected in early winter 2021 in Newfoundland and Labrador, Canada. It has now been conﬁrmed in nearly all U.S. states and Canada provinces, in commercial poultry, backyard ﬂocks, many species of wild birds, and several species of mammals.
What do I do if I ﬁnd a dead bird in Washington?
Do not attempt to move sick wild animals to a veterinarian or rehabilitation center, or to your home, as this can spread the disease. Members of the public who find sick or dead birds should report them immediately using this online form. As resources are available,< biologists may respond to remove carcasses and, if in an area or species where avian influenza has not been confirmed, test for the virus. Due to the magnitude of this outbreak, Washington Department of Fish and Wildlife staff will not be able to respond to all reported cases. Reports of suspected avian influenza in domestic poultry flocks should be sent to the Washington State Department of Agriculture. Call (800) 606-3056 or read more about how to protect poultry and other domestic birds.
What are inﬂuenza viruses?
There are three types of inﬂuenza viruses: A, B and C. Avian inﬂuenza A viruses, which include the virus that has been detected in seals in 2022, occasionally cross over the species barrier from birds. They cause clinical disease and epidemics in people and other mammals, including seals. Tthese are known as “zoonotic diseases,” meaning they have the potential to spread between animals and people and their pets. Inﬂuenza B viruses are primarily a virus in people with no known wildlife reservoir, and cause clinical disease epidemics in people. However, they have been isolated from apparently healthy gray and harbor seals in the North Sea in Europe. Inﬂuenza C is a virus that infects people and may cause a mild respiratory illness but is not thought to cause epidemics in people.
Inﬂuenza A viruses are divided into subtypes based on two proteins on the surface of the virus: hemagglutinin (H) and the neuraminidase (N). There are 16 diﬀerent hemagglutinin subtypes and 9 diﬀerent neuraminidase subtypes. Inﬂuenza A viruses can be further broken down into diﬀerent strains. Subtypes may be species speciﬁc, so not all subtypes are found in all species. Both Inﬂuenza A and Inﬂuenza B viruses have been documented to cause illness and deaths in seals in North America and in Europe. Learn more about ﬂu viruses.
What is bird ﬂu?
Avian inﬂuenza, or bird ﬂu, refers to a respiratory disease caused by infection with a type of inﬂuenza virus. Avian ﬂu viruses normally spread among wild water birds, such as ducks and geese. These viruses can spread to domestic poultry, such as chickens, ducks, geese, and guinea hens. Avian ﬂu viruses do not normally make humans sick, but human infections with avian ﬂu viruses have occurred. People who have regular contact with poultry or wild birds are most at risk.
What is the risk to humans from the inﬂuenza virus?
Inﬂuenza A viruses especially have a relatively high rate of mutation, or change, which may allow them to cross species barriers and may cause severe disease in their new hosts. The Centers for Disease Control, the National Wildlife Health Center, National Institute of Health, state agencies, and other organizations like NOAA monitor events involving animal inﬂuenza viruses very closely. We advise the public to take precautions for themselves and their pets.
What is the risk to humans from the H5N1 Highly Pathogenic Avian Inﬂuenza?
According to the CDC, the health risk posed to the general public is low; however, they recommend precautions. People and their pets should avoid all contact with sick or dead wildlife because HPAI can spread between animals and people (and their pets). Although the risk of infection to the general public remains low, beachgoers should not touch live or dead seals or allow pets to approach seals. They should maintain a safe distance of 100 yards.
Are there any risks to pets?
Yes. Dogs and cats also share infectious diseases with marine mammals. They should not be allowed to approach live or dead marine mammals and wildlife or to consume dead marine mammals and wildlife or their parts. Dogs are susceptible to a canine inﬂuenza virus. Additionally, sick seals that do not feel well may bite you or your pet if you get too close. NOAA Fisheries recommends contacting your pet’s veterinarian to discuss the potential risk to pets in your local area, or if your pet bites or is bitten by a seal.
What should I do to protect myself and my pets against these viruses?
You should never approach or allow a pet to approach a live or dead marine mammal or wildlife. Seals, like other marine mammals (dolphins, whales, and sea lions), are protected under the Marine Mammal Protection Act. People and their pets must maintain a safe distance of 150 feet so as not to disturb the animal, which may be just resting on the beach, and to avoid injury to themselves, their pets, or the seals.
While seals look cute, they are wild animals and can transmit disease. Some safe viewing tips:
- Stay at least 100 yards away from seals or other marine mammals
- Keep dogs on a leash and don’t allow them to approach seals—seals and dogs can easily infect each other with diseases since they are closely related species
- Call NOAA Fisheries’ stranding hotline at (866) 767-6114 or a local marine mammal stranding network member
Has inﬂuenza ever been detected in seals in the United States or globally?
Yes, inﬂuenza A viruses have been detected in marine mammals in the United States and other parts of the world. These cases occurred both during outbreaks in which the virus caused clinical disease and/or mortality events in seals, and in apparently healthy individuals not associated with any outbreak. Examples of previous inﬂuenza events:
- 2023: H5N1 in a sea lion and sea otter in Chile
- 2022: H5N1 in harbor and gray seals in Maine and Canada, harbor and gray seals in Scotland, sea lions in Peru, harbor porpoise in Sweden, bottlenose dolphin in Florida, a common dolphin in Peru
- 2021: H10N7 in a harbor seal in British Columbia
- 2021: H5N8 in harbor and gray seals in the United Kingdom; harbor seals in the Wadden Sea
- 2017: H3N8 in a gray seal in the United Kingdom
- 2014–2015: H10N7 in harbor and gray seals in the North Sea
- 2012: H4N6 in Caspian seals in Russia
- 2011: H3N8 in harbor seals in Maine, New Hampshire, and Massachusetts
- 2010 and 2022: H1N1 detected in elephant seals in California
- 1991–1992: H4N6 and H3N3 in seals in Massachusetts
- 1982–1983: H4N5 in harbor seals in the Northeast United States
- 1979–1980: H7N7 in harbor seals in the Northeast United States
How does the inﬂuenza virus spread among seals?
Inﬂuenza viruses are usually spread through inhalation of respiratory particles, direct contact with feces, or between animals, including between mothers and pups. Animals can also be exposed to the virus through other entryways such as the eyes, mouth, stomach, skin wounds, and the urogenital tract.
How do seals catch inﬂuenza?
While this is still an area of active investigation, we believe most cases initiate from waterfowl or seabirds, which are the natural reservoirs for a diverse range of Inﬂuenza A variants. Seals can be exposed by being close to birds through respiratory droplets or exposure to infected bird feces. Once a new variant of inﬂuenza has entered into a seal population, it is then often able to spread from seal to seal.
How do inﬂuenza viruses aﬀect seals?
The most common organs aﬀected are the lungs and brain. Sick animals may appear thin, have respiratory clinical signs such as coughing or diﬃculty breathing, and may exhibit teary eyes, lethargy, and/or abnormal behavior due to a brain infection.
Is there anything you can do to protect the seals?
One of the challenges of wildlife management is managing large, healthy populations; harbor seals in this region are one such group of wildlife. We have instituted testing and management within our rehabilitation facilities to reduce the potential spread of the disease in rehabilitation centers and to reduce exposure for employees and their pets. The public can also help by keeping themselves and pets far away from seals in the wild.
If the animals are sick, when does the Marine Mammal Stranding Network consider euthanasia for marine mammals?
Situations that may necessitate the consideration of euthanasia include an animal’s suﬀering with severe injuries (either internal or external) or illness (e.g., disease or poor body condition). If an animal has a serious injury or illness from which recovery is unlikely, euthanasia may be the best and most humane course of action to alleviate its prolonged suﬀering. Each scenario will be carefully evaluated on a case-by-case basis to provide the most humane outcome for the individual animal. The decision to euthanize a marine mammal is made by the NOAA Fisheries Regional Stranding Coordinator, the local Stranding Network group, the attending veterinarian, the Marine Mammal Health and Stranding Response Program staﬀ, and/or other management agencies, depending upon the circumstances.
Are seal rehabilitation hospitals closing or closed to new patients?
Currently, Washington rehabilitation facilities are open. New seals are admitted on a case-by-case basis, and are quarantined and tested prior to or upon arrival. Other facilities in the West Coast Region may pause intakes of animals while diagnostically screening current patients. They may need to limit or restrict new patients to be able to enact the stricter quarantine precautions that an identiﬁed infectious disease requires.
What guidance has been provided to the marine mammal stranding response teams regarding handling seals and potential human health impacts?
The Network normally follows safety precautions for handling stranded seals as provided in each organization's safety plans and NOAA Fisheries’ Best Practices for Marine Mammal Stranding Response, Rehabilitation, and Release. In addition, we have distributed fact sheets and other materials on avian inﬂuenza and infectious disease prevention to our network responders.
Does eating seafood pose a risk?
No. Inﬂuenza viruses do not cause disease in ﬁsh so there is no risk of catching this virus by eating ﬁsh.
Where can I ﬁnd additional information on harbor seals?
What should people do if they see a person or animal harassing a seal?
To report violations or for more information on NOAA’s Oﬃce of Law Enforcement call the toll- free number: (800) 853-1964.