Greater Sage-Grouse (Centrocercus urophasianus)

Greater Sage-Grouse

Centrocercus urophasianus

IDAPA Classification: Upland Game Bird

Health Issues Which May Affect This Animal

West Nile Virus

What Causes This Disease?

West Nile Virus (WNV) is caused by a mosquito transmitted virus (Arbovirus) that is carried by birds, especially magpies, crows and ravens. Other birds, mammals, reptiles, horses and humans can contract the virus through the bite of a WNV infected mosquito. West Nile virus has a complex lifecycle between certain birds and certain mosquito species. Some birds like crows, magpies, ravens, birds of prey, and sage grouse are highly susceptible to WNV and it is often fatal in these species.

Where Is The Disease Found?

West Nile Virus is native to the northern parts of Africa, the Middle East and occasionally southern Europe. After introduction to North America in 1999, the virus spread to every state and most of the southern provinces of Canada. The first detection of WNV in Idaho was in 2003 and the disease has been reported annually ever since.

Signs of Disease

Signs of WNV vary by depending on the species affected. Some birds carry the virus, remaining asymptomatic while some species are highly susceptible. Clinical signs can range from no reaction to the virus to mortality, especially in corvids (crows, ravens and magpies). Finding dead ravens, crows, magpies, and birds of prey may indicate WNV is present in an area. WNV has also affected sage grouse in some areas of Idaho and the intermountain west. Birds usually do not show any clinical signs when infected with WNV. Chickens can be infected with WNV and not become sick. However, natural disease due to the virus has been reported in domestic geese, ducks, pigeons and chickens.

Read More About West Nile Virus