Conservationists are concerned after 20 wild bighorn sheep were recently found dead near Grand Forks.
The Wild Sheep Society of BC is calling it a "devastating disease event," that has ravaged the local at-risk herd.
They have determined the sheep died from bluetongue, also known as epizootic hemorrhagic disease, a virus which has no specific treatment.
The animals were discovered due to a collaring project the WSSBC has been undertaking for the past two years. When an animal's GPS collar stops moving for a set period of time, volunteers take to the field to find out what happened.
The death count of 20 is expected to rise.
"In an area where we would expect to see 50 sheep at once, it was heart-wrenching to witness so much death," said Peter Gutsche, WSSBC director.
"Our members will be on site again over the next few days to get a better idea of just how many animals are affected. We know that there are many sheep and whitetail deer that are lost to this disease so far."
The WSSBC contributed funds to the purchase of the swathe of land where the sheep were found east of Grand Forks, in support of the Southern Interior Land Trust for conservation.
"Although there is nothing we can do to stop this event as it has occurred, we will be working with SILT to enhance habitat in the future."