Since the first outbreak of the virus in 2022, the bird flu (H5N1) has spread across the United
StatesI.n California, the virus is sending a warning not only for the farmers, but for the public and residents.
Colleen O’Rourke, Riordan biology teacher and a 4H member, said, “H5N1 is a strain of the virus influenza, which causes a series of symptoms in humans and other animals which we often label as ‘the flu’.”
A bird rests in its nest in a local neighborhood.
Different strains of influenza specialize in infecting specific types of animals, but some strains of influenza mutate enough to beable to “jump ship” and infect other types of animals.
“I’ve read a hypothesis that in fact all strains of influenza– which is the specific type of virus that causes the actual ‘flu’–originally came from birds and started crossing over into human populations thousands of years ago,” O’Rourke said.
With several birds already dead and the flu is spreading to animals like cows and human beings, scientists worry this could grow into a more serious health problem for others if not maintained.
“H5N1 is a strain of avian influenza, meaning it’s most commonly found in birds, but recent evidence indicates that it is mutating enough to infect mammals like cows, cats, and humans,” O’Rourke explained.
A chicken sits behind a fenced coup in Northern California.
H5N1 has spread throughout wild birds. In the state of California, farms have been affected more than others, with several birds like chickens, ducks, and turkeys affected since the virus started in 2022.
The virus not only has stopped at the birds but according to the USDA, it has spread to thousands of dairy farms across 17 different states of the country.
O’Rourke said, “Birds are extremely susceptible to respiratory infections even under the best circumstances, so when a respiratory-specific virus enters an agricultural poultry flock– where many birds are kept in smaller areas together – it can spread like wildfire.”
Vet doctors from UC Davis School are analyzing the spread, watching the movement very closely. Studies show that the spread towards cattle is concerning.
The virus started spreading into food, tools, and through animals. Once the cattle get sick, milk supply usually plummets and the cows have a loss of appetite and they get fevers. Some cows that might not die from the flu will be weak for a long period of time, affecting the animal and the price of the cattle.
While most are fixated on the animals being harmed by the virus, humans have also been getting infected as several cases have been reported in California.
“Apparently yes, there have been a couple documented instances of humans becoming sick with H5N1, including a few deaths. It is still uncertain whether there was human-to-human transmission in these cases, though, but it’s still an important reminder to take biosecurity seriously in our lives,” O’Rourke explained.
Between September and December 2024, around 40 people were tested for the virus or H5N1 and all ended up being positive. Some of those people were farmers and some were regular citizens living in California. One of the cases had a child who was near the virus but wasn’t infected.
Being able to go from human to another human with this virus is rare. The Centers for Disease Control and Prevention (CDC) is also watching the spread of the virus.
“Anytime a virus jumps species, we watch for mutations that could make it easier to spread,” the CDC explained in a recent report.
“We are concerned about potential future risks, especially if the virus becomes more transmissible among people.”
Health experts want others to work their farms with protective material to stop the risk of any humans being infected.
Two seagulls take in the views at Ocean Beach.
The economy of California has been affected by the H5N1 virus and is already impacting many people living near these infected areas. Various farms have isolated birds to stop the spread, causing economic issues.
Dairy farms are also challenged by setbacks. The CDFA (California Department of Food and Agriculture) has teamed with the USDA and farms to stop the virus and give support. Veterinarians are also at stake. Many doctors are doing their best to protect farms, but also work with small amounts of information.
The UC Davis School of Veterinary Medicine will continue to update the public on risk of being infected as research continues.
