Officials won't say if the person was a man or a woman or which health region was involved.
The province says the person was one of five adults under investigation for West Nile virus infections.
Three other people are being treated for West Nile neurological syndrome and one person has the less serious West Nile virus.
Most people who become infected with West Nile virus experience no symptoms or mild illness such as fever, headaches and body aches.
But there is a small risk of the more serious West Nile neurological syndrome, which includes encephalitis, an inflammation of the brain.