Most people get West Nile virus after being bitten by a mosquito that has fed on an infected bird. (CBC)

B.C.'s Animal Health Centre confirms a dead crow from the Central Okanagan has tested positive for West Nile virus.

The discovery marks the first time the disease has been found in a B.C. crow and officials say it is also the first sign this year that the virus is active west of the Rockies.

No human cases of the potentially serious illness have been reported in B.C., this year.

Interior Health medical health officer Dr. Rob Parker says the disease was confirmed in mosquito pools in the South Okanagan last year and two human cases were reported in the same area last August.

West Nile virus is spread to humans, horses and other types of birds and animals by mosquitoes that have fed on an infected bird.

Eighty per cent of those who contract the virus have no symptoms, but about 20 per cent can suffer headache, fatigue, rash, fever, sore joints and muscles and, occasionally, nausea.