The anthrax outbreak in Saskatchewan that's being called the worst in decades may be diminishing.

For the first time in weeks, the Canadian Food Inspection Agency is reporting no additional animals have died of the disease in Saskatchewan.

"The rate has certainly slowed down," CFIA spokesman Greg Douglas said Wednesday. "It seems a lot of the vaccination efforts have paid off."

According to the CFIA's Wednesday update, 649 Saskatchewan farm animals have died, most of them horses and cattle. Another 134 animals have died in Manitoba.

It's the worst outbreak since the 1950s, when the federal agency began collecting anthrax statistics.

Douglas said anthrax spores are still in the soil and there will be additional animals deaths over the next six months.

However, after about 500,000 anthrax vaccine doses were given to farm animals, a level of immunity has been built up that's keeping the outbreak in check.