'It's more like a poison': Experts, equestrians warn against using horse dewormer to treat COVID-19

Ivermectin is a drug used to treat parasites in mainly horses and cattle, but misinformation about the dewormer has attracted a different type of herd – people who believe it can prevent COVID-19.

Misinformation about ivermectin has spread online in recent weeks, prompting concerns from veterinarians and those in the equestrian industry.

"It's more like a poison that's going to kill the worms in their systems, so I can't imagine that it would be very good for human consumption," said Claire Bevan-Stewart, owner of Willow Equestrian in Guelph.

Bevan-Stewart said she's seen a surge in inquires and sales of ivermectin, raising her suspicion about what it is being purchased for.

"We decided because of the influx of interest and possibly with non-horse people we decided to take it off the shelves and off the website," she said.

That decision came around the same time Bevan-Stewart says Ontario's Animal Health and Welfare Branch wrote to veterinary retailers to not sell ivermectin for human use.

"Don't take ivermectin, it's not effective at COVID and it's likely to be very toxic," said University of Guelph veterinary professor Dorothee Bienzle.

She said there is no proof of the dewormer's effectiveness against COVID-19, but it is proven that a dose meant for livestock is up to twenty times stronger than what would be prescribed for people to treat infections like head lice.

"That's way too much and they get mainly what is called neurotoxicity and they get irritation of the intestines, nausea, vomiting," Bienzle said.

In August, Health Canada issued a warning against taking ivermectin to treat COVID-19 due to serious health dangers, adding "to date, Health Canada has not received any drug submission or clinical trial application for ivermectin for the prevention or treatment of COVID-19."