WSU lab confirms bluetongue virus killing deer, livestock

By Charlie Powell, College of Veterinary Medicine

PULLMAN, Wash. – The Washington Animal Disease Diagnostic Laboratory located in the Washington State University College of Veterinary Medicine has confirmed bluetongue virus (BTV) in 42 animals submitted from Washington and Idaho this fall.

All samples tested negative for epizootic hemorrhagic disease virus (EHD).

The distinction between BTV and EHD is important: While both can cause similar signs in the same species, bluetongue can affect international trade while EHD is uncommon in cattle.

WADDL routinely tests for both viruses simultaneously when samples are submitted requesting testing for one or the other disease.

Most of the samples submitted to WADDL were from white-tailed deer. Other affected species included cows, domestic sheep, bighorn sheep, mule deer and a yak.

The laboratory detected BTV in animals from Whitman, Spokane, Asotin, Garfield, Pend Oreille and Stevens counties in Washington, as well as Latah, Clearwater, Canyon and Nez Perce counties in Idaho. Samples from cattle and bighorn sheep submitted from Churchill and Mineral counties in Nevada were also confirmed to have BTV.

The virus was typically detected in samples of blood or blood-rich organs including lung, spleen or bone marrow.

Several identical samples were sent to the National Veterinary Services Laboratories in Ames, Iowa for subtyping.

Bluetongue is an infectious, insect-borne, viral disease primarily of domestic and wild ruminants – animals with multi-chambered stomachs. Infection does not spread directly from animal to animal. In addition to deer and elk, the virus can infect cattle, domestic and wild sheep, goats, camels, antelope, bison and yaks.

The signs of BTV infection may include high fever, profuse salivation, nasal discharge, facial swelling and breathing difficulty. In severe cases, lung damage results in poor blood oxygenation, which may make the tongues and lips of animals appear bluer than normal – a sign called cyanosis.

Bluetongue infections can both sicken and kill large numbers of animals depending on the species. Not all animals develop symptoms, but those that do may decline rapidly and death may follow in less than a week.

Animals that do not die may recover slowly or may require euthanasia due to welfare considerations.


Charlie Powell, WSU College of Veterinary Medicine public information officer, call or text 509-595-2017,