Invasive and toxic hammerhead worms make themselves at home in Ontario

Ontario is now home to an invasive and toxic worm species that can grow up to three feet long and can be dangerous to small animals and pets.

Ontario is now home to an invasive and toxic worm species that can grow up to three feet long and can be dangerous to small animals and pets.

Numerous reports have been made that hammerhead worms, also known as the broadhead planarian, have been recently spotted in Newmarket, Hamilton, and the Kitchener area.

“They are here,” John Reynolds, a laboratory biologist and worm expert told CTV News Toronto on Friday. “People are surprised to see them because they’re just so unusual. People are not used to seeing them. They are a semi-tropical organism originally.”

The worms, originally from Southeast Asia, were likely brought into the province accidently through nursery stock material possibly from the U.S., Reynolds said. For years, the worms have been spotted across America and in Quebec.

“They don’t go very far on their own. They need to be transported,” Reynolds said. “They can spread quickly because if you cut them up, each piece becomes a new individual.”

The hammerhead worm, which gets its name due to the flat shape of its head, has a very dangerous neurotoxin called tetrodotoxin which is also found in pufferfish, Reynolds said. While the toxin can be lethal for small animals, it will only produce a rash for people.

“They are not seriously harmful to people,” he said. “They may make an awful rash and make your hands tingly for a bit. If you ingest one by mistake, it will just make you nauseas. It certainly won’t be fatal.”