Ontario residents warned of 'venomous' caterpillar that you should never touch

Residents in part of Ontario have been issued a stern warning by local health officials, advising the public of a supposedly "venomous" species of caterpillar that can be harmful to humans if handled.

The Renfrew County and District Health Unit sent out a PSA last week cautioning that "the Hickory Tussock Moth Caterpillar is a venomous caterpillar that may be in Renfrew County and District."

Despite anecdotal claims of venom mentioned by this local health unit, the caterpillar species — known by the scientific name of Lophocampa caryae — has never actually been confirmed to possess venom. 

However, that doesn't mean it is a good idea to touch one.

Officials describe the species as "white and fluffy, [with] black chain-like markings on its back and long black hairs that stick out near the front and back," and stress that locals would be best to "not touch them!"

While the species may appear soft and fuzzy to the untrained eye, its fur-like covering is actually a network of hairlike setae that act like tiny hypodermic needles, and are more akin to the barbs on a cactus than the fur on your household pet.

If these microscopic needles are touched by, say, an unwitting child mistaking the bugs for fuzzy friends, victims may suffer a reaction similar to poison ivy with symptoms that can include a burning sensation with swelling and pain. 

Some people may even experience more severe symptoms like nausea and headaches, while, in rarer cases, the caterpillars can trigger an allergic reaction.

Experts recommend that if exposed to a Hickory Tussock Moth Caterpillar, you should immediately scrub the affected area with soap and water, and remedy itching and swelling with calamine lotion and ice packs.

Anyone suffering a more severe reaction from these tiny hair-like barbs is advised to seek medical treatment.

While the caterpillar is native to a range spanning much of eastern North America, the species has spread to parts of Canada where it had previously not been documented, like Prince Edward Island.

It is present throughout Southern Ontario, and has strayed further north and east within the province in recent years. One of the caterpillars was even spotted as far north as Sudbury this summer and reported via online identification platform iNaturalist.

So, maybe don't touch the soft, fuzzy-looking caterpillar.