Vancouver Island's health authority is warning residents about a possible exposure to avian flu at a petting farm in Campbell River, B.C.

The owner of Holly Hill Farm said Sunday on Facebook that each of their approximately 50 chickens and ducks were put down after they learned avian flu, also known as H5N1, was discovered in their flock.

"My chickens and ducks each had names and were more than just 'livestock,'" Katie Denne wrote.

Avian flu spreads quickly through wild and domestic birds, and several B.C. farms have been impacted in the past few years. While the risk is low, it can spread to humans.

Island Health is advising anyone who visited the farm on Oct. 26 or 27 to monitor for symptoms associated with avian flu, including but not limited to cough, fever, sore throat, runny nose or red, watery, itchy or painful eyes.

Anyone who visited the farm at that time and is experiencing avian flu symptoms 10 days later should contact the health authority. Island Health said it is directly contacting school groups and others who visited the farm privately.

The farm is working with authorities to take the appropriate action, according to Island Health.

Denne said in her social media post that when they learned their flock had been infected, they immediately contacted the health authority and the Canadian Food Inspection Agency.

"We were mandated to kill all of our birds in order to prevent the spread and help protect food sources," she said.

According to the federal government, there has only been one human case of H5N1 recorded in Canada. There have been 44 reported cases in humans in the U.S., according to the Centers for Disease Control and Prevention. More than 900 human cases of the disease have been reported worldwide since 1997, the Canadian government says, though the number of human cases has gone down since 2015.

But the number of cases in birds is increasing, the B.C. Centre for Disease Control says.

"Since 2022, there has been unprecedented global spread of highly pathogenic avian influenza A (H5N1 and related viruses) in many wild bird species and domestic poultry," the centre says on its website.

The disease has been found in mammals, including skunks, marine animals and livestock such as cows.

Most recently, the disease was found in pigs on a Washington state farm.

Dr. Allison McGeer, an infectious disease physician at Sinai Health in Toronto, said an influenza strain is specific to the mammal it infects.

"Every time it's in a new mammalian species, that's evidence that this strain can change enough to infect a new species," she told Daybreak South host Chris Walker.

She said that so far, the people who are contracting the disease have gotten it from cows or chickens.