CHINCOTEAGUE, Va. (WVEC) — The Chincoteague Volunteer Fire Company announced the death of another Chincoteague pony Sunday due to "swamp cancer."

Lyra, the mare who battled the disease the longest, had to be laid down.

According to the Facebook post, the current treatments seem to work at first, but then the fungus comes back full force.

A new drug to treat the four remaining ponies is expected to arrive Tuesday. The post states the Fire Company isn't aware of the specifics on the drug, but they are going to continue to do what they can to save the ponies.

The Facebook post provides some optimism by stating the buyback ponies are looking good.

Back in October, seven ponies were inflicted with the illness. The first pony to die from the disease was Essie, who died on October 30. Rain Dancer, who died December 4, was the second pony to die from the disease.

Three mares were donated to help boost the herd's population.