Overview:
On December 18, 2024, Governor Gavin Newsom declared a state of emergency for the ongoing spread of H5N1 in California dairy cattle herds. This declaration has been made preemptively to ensure state and federal agencies have easier access to the resources needed to combat this disease outbreak, but for all of us with clear memories of the early days of the coronavirus outbreak, this news is still worrisome. H5N1, better known as “bird flu” or avian influenza, has been detected in dairy herds across the state, and is expected to impact dairy and egg production for the whole of the United States. It has also been detected in wild birds in Santa Clara County, and diagnosed in several humans in the San Francisco Bay Area. While we won’t be able to provide you with continuous monitoring of this issue, we did want to provide our membership and local bird appreciators with a breakdown of the basics of this disease, how it is likely to impact the everyday birder, and what you can do to mitigate the risk of disease spread while still enjoying your usual activities.
For the most up to date statistics of the H5N1 outbreak, please look to the CDC’s Bird Flu situation summary.
The disease:
H5N1 is a mRNA virus, which means that mutations are to be expected, and are part of why this virus has been able to jump between hosts of different species (birds to cows to humans). At this point there have been no cases of human to human disease transmission, but this may change as more people are exposed. The propensity of the virus to mutate will likely make the development of vaccines difficult, though it is important to keep in mind that our health system has a great deal of experience in developing flu vaccines.
Avian influenza is mostly spread by direct contact with infected animals. It can also spread through contact with the nasal, eye, or oral secretions of the infected, as well as their excrement. Contact with excrement has been the most commonly documented method of disease transmission, but airborne transmission is also possible.
Symptoms to look for:
Human symptoms include:
fatigue
cough
shortness of breath
conjunctivitis (red eyes)
flu-like respiratory symptoms
fever
Like other flus, this does have the potential of posing a serious health risk, especially to individuals with compromised immune systems, children, and the elderly.
Bird symptoms:
fatigue and lethargy
nasal discharge
diarrhea
purple discoloration or swelling of various body parts
sudden death
Avoid contact with dead birds when possible, and monitor your bird feeders and baths, as these areas can become hotspots for disease spread. These symptoms will also be present in backyard flocks that have been infected.
Dog and cat symptoms:
lethargy
fever
reduced appetite
difficulty breathing
neurological signs like blindness, tremors, and seizures
If you see signs of these symptoms in your pets, you should immediately contact your veterinarian, and let them know if your pet has come in contact with a dead bird, or has consumed unpasteurized milk. Because there are multiple respiratory illnesses that share these symptoms, additional tests will likely be needed.
Managing Exposure:
Avian influenza is naturally occurring in wild bird flocks, particularly in large flocks of waterfowl like we experience in the wetlands here in Santa Clara County. Changing or cleaning your shoes between visits to birding sites can be a good way to avoid potentially spreading the disease.
Wash or sanitize your hands if you do come in contact with bird droppings, feathers, or dead birds.
Keep pets or home flocks of poultry away from wild birds and their droppings.
If your pet goes outdoors keep them away from wild birds, poultry, and cattle, as well as their environments.
Avoid consuming raw meat and poultry, or unpasteurized milk.
Seeing sick birds in your yard? Remove and clean your feeders and bird baths. Feeders and baths should be removed for 2-3 weeks in order to allow wild birds to disperse.
Report dead birds to the California Dead Bird Hotline at (877) 968-2473 .
Remember:
At this point bird flu has not become an immediate threat to human health and safety. The CDC is actively monitoring the infection rate in people, as well as the country’s poultry and cattle operations.
Keep an eye on your bird feeders and baths, and exercise common sense precautions if you do have to deal with dead birds. This is very much a developing situation, and it is likely that we will see an increasing number of cases as the disease progress. There is a very good chance that we will see the impacts of this virus in the production of eggs and dairy at the grocery store.
You can find the up to date disease statistics here.
Do not bring sick or injured birds to the Santa Clara Valley Bird Alliance.
Sources:
Bird Note, Season 6, Episode 6
NPR, Bird flu update: California declares emergency and U.S. sees 1st severe human case
American Veterinary Medical Association, Avian Influenza
US Centers for Disease Control and Prevention, Avian Influenza situation summary
US Department of Agriculture, Avian Influenza