It can occur as a co-infection with Lyme disease, as both are transmitted to humans by the same species of tick.

[1] Over the last decade, there has been a surge in the number of cases and an expansion of its geographic range.

[2] The disease was first isolated from the brain of a boy who died of encephalitis in Powassan, Ontario, in 1958.

[3] This disease is classified as a zoonosis, originating in animals, often found in rodents and ticks, with subsequent transmission to humans.

[4] Symptoms manifest within 7–10 days and include fever, headache, partial paralysis, confusion, nausea and even coma.