N.W.T. wildlife officials now say the anthrax outbreak among bison is the largest they've seen in the territory.

So far approximately 340 bison have died. The last big outbreak in 1994 affected 172 animals.

The Department of Environment and Natural Resources has had to bring in staff from other regions and has also hired emergency firefighters from Fort Providence to help dispose of the carcasses.

Terry Armstrong, a wildlife biologist with ENR, is asking anyone who comes across dead bison to notify the department.

"The focus right now is to finish the disposal of all carcasses that we find and to make sure those sites are decontaminated as best we can," he said.

"What causes an outbreak and what causes it to taper off or end is not well understood, but it seems cooler weather and rain tend to help."

People are also advised not to approach or touch the carcasses. Anthrax bacteria are found naturally in soil in the region and when hot, dry weather follows a dry season, bison can inhale their spores and become infected.