Newcastle disease is a viral disease that can affect a wide variety of avian species, both wild birds and domestic fowl.

The disease is of great concern throughout much of the world's agricultural community because it is highly contagious and can cause severe disease in poultry.

Strains that produce mild and moderate forms of the disease are sometimes found in domestic poultry and pigeons. The most severe forms of the disease, known as velogenic Newcastle disease (VND), are caused by highly pathogenic strains of the virus. VND can cause severe mortality in chickens.

Newcastle disease is a provincially reportable disease for domestic chickens, bantams, pheasants and peafowl; these birds when kept in captivity: domestic turkeys, ostriches, emus, rheas, pigeons, doves, quail, guinea fowl and wild turkeys; and domesticated ducks and domesticated geese.

Newcastle disease is a provincially notifiable disease for wild birds.