Carol Baldwin
Local Journalism Initiative Reporter
Wakaw Recorder
In late January, U.S. health officials announced that a new strain of avian flu, H5N9, was discovered on a duck farm in Merced County, California.
They quarantined the farm and destroyed nearly 120,000 birds. H5N9 has the potential to be more virulent for birds and other farm animals, but it is important to know that it does not pose any greater risk to humans, says Rais Vohra, MD, professor at UC San Francisco, Fresno and interim Health Officer for the Fresno Department of Public Health (DPH).
Health officials and scientists are monitoring H5N9 closely, however, because its evolution alongside seasonal flu and other strains could, in the future, produce new versions of the virus that spread more easily among humans. Both H5N1 and H5N9 are different strains of avian flu. Similar to human flu, avian flu also has various strains.
Highly Pathogenic Avian Influenza (HPAI) or H5N1, also called “bird flu,” is the strain that has dominated the current outbreak. The virus primarily affects birds but can and has infected both wild and domestic mammals, including pigs, cows, cats, dogs and humans. It spreads rapidly among wild birds and poultry.
Bird flu is an influenza that is called a zoonotic infection. That is, it’s a virus that primarily infects animals, especially birds in this case. Unfortunately, influenza can change itself genetically very easily and thereby create many different variations of itself. As observed during COVID, variations can increase the likelihood of infection both in typical hosts and other animals.
The current global outbreak of H5N1, which began in 2021, has become one of the most widespread avian influenza outbreaks in history. The virus has heavily impacted wild bird populations, poultry farms and some mammalian species across multiple continents, including North America, Europe and Asia.
In Canada, H5N1 was first detected in wild birds and domestic poultry flocks in 2022, leading to significant losses in the poultry industry. Ongoing surveillance efforts are focused on wild birds, poultry and livestock to detect and contain the virus. H5N1 is a highly lethal virus in poultry, including chickens, turkeys and ducks, who are extremely vulnerable to H5N1. Infected flocks often experience sudden, high mortality rates, and the disease spreads rapidly.
Cats are also highly susceptible to H5N1. When cats become infected, the virus can spread throughout their bodies, causing severe respiratory and neurological symptoms. In many cases, H5N1 is fatal in cats. Cats can become infected by eating infected birds or consuming raw milk from infected cows. Some things can be done to protect your pets. If possible, keep cats indoors. Cats that hunt wild birds or roam outside are at high risk of contracting the virus. Cats that live outdoors in barns or shops should be monitored for potential illness as the songbirds return in the spring. Secondly, do not feed raw milk or meat to pets as the raw product may be from an infected animal, which can then spread H5N1 to pets. Watching for symptoms of illness in pets, such as coughing, sneezing or difficulty breathing; loss of energy or appetite; and vomiting, diarrhea or signs of nervous system problems (e.g., tremors or seizures) should go without saying. If pets exhibit any of these symptoms, owners should seek veterinary care immediately.
H5N1 is a serious virus, and while it is highly lethal in poultry and cats, the strain in dairy cattle appears to cause less severe disease with only a mild to moderate illness. However, since the virus can adapt and evolve, it is essential to remain cautious. The CFIA continues to work closely with producers to ensure early detection and prevention of H5N1 infections in livestock. Producers are encouraged to report any unusual illness in their herds to a veterinarian. Infected cows show decreased milk production, changes in milk quality, and some lethargy but do not suffer from the same high mortality seen in other species. Importantly, the virus has been found in raw (unpasteurized) milk from infected cows, and infected cattle can shed the virus into the environment, creating opportunities for the virus to spread to other animals and potentially to humans.
To date, there have been no detections of H5N1 in Canadian dairy herds. The situation in Canada is being carefully monitored, and the Canadian Food Inspection Agency (CFIA) has implemented surveillance and testing programs to monitor dairy cattle for H5N1. Pasteurized milk in Canada remains safe. However, the CFIA continues to advise that drinking raw milk poses a significant health risk. Pasteurization effectively kills harmful viruses and bacteria while maintaining the nutritional properties of milk.
Poultry remains at the highest risk for H5N1 infection. To protect flocks, keep poultry away from all wild birds, including songbirds. The main concern with songbirds is the chance that a rare individual might transmit an infection to poultry. Since poultry are so much more vulnerable than songbirds to HPAI, one transmission is all it takes. Do not allow access to ponds, sloughs, or other untreated water sources visited by wild birds, and keep wild birds away from areas where flocks are fed. Owners of small or backyard flocks are recommended to remove bird baths or feeding stations to deter wild birds from congregating close to where flocks are housed.
The signs of illness in poultry include a sudden loss of energy or appetite, reduced egg production, swelling around the head, neck or eyes, and sudden and unexpected deaths in multiple birds. By law, any suspicion of HPAI must be reported to the Canadian Food Inspection Agency (CFIA). If any of these symptoms appear in a flock, the owner must report them to a veterinarian as soon as possible. Small flock and backyard poultry producers can submit deceased birds for free diagnostic testing through the Saskatchewan Small Flock Poultry Surveillance Program. Additional program details and how to submit samples can be found by visiting saskatchewan.ca and searching for “small flock surveillance.”
Use strong biosecurity measures such as wearing clean, barn-specific clothing and boots when caring for poultry; keeping visitors out of poultry areas unless necessary; and regularly cleaning and disinfecting coops, feeders and water containers. By protecting animals through biosecurity measures and avoiding raw milk or direct contact with infected wildlife, the risk of spreading the virus can be reduced. Simple steps can make a significant difference in keeping animals, families and communities safe.
People who are in direct contact with infected animals, raw milk or contaminated environments are at higher risk than the general population, where the risk is low. People can take important steps to protect themselves from H5N1 by avoiding contact with sick or dead wild birds, including their feathers, and contacting wildlife services to report the dead birds.
Wear protective gear when working with poultry or livestock, like gloves and masks, and wash hands thoroughly after handling animals. Drink only pasteurized milk, which is safe and free of H5N1 and other viruses and bacteria that can cause illness. And, of course, monitoring one’s health. If you or someone you know experiences flu-like symptoms, such as fever, cough or shortness of breath, after being near poultry, dairy cattle or wildlife, seek medical attention immediately.
