RENO, Nev. -- Nevada wildlife officials are waiting to see if their decision to slaughter a diseased herd of bighorn sheep earlier this year paid off.

State officials decided in February their only choice was to kill the last 27 survivors of a sickly herd that once totaled about 100 near the Oregon line. The killing was part of an effort to combat the spread of bighorn pneumonia that's hit several western states.

In January, the Arizona Game and Fish Department reported that tissue samples from three ewes confirmed the animals had a strain of pneumonia bacteria.

In January, Game and Fish officials said they would to continue to monitor the sheep population in the Black Mountains in northwestern Arizona.

The disease threatens efforts to rebuild the native populations that were nearly extinct 50 years ago.