Fire ants have been discovered in two western Kentucky counties in recent weeks and efforts have been made to eradicate the ants known for their aggressiveness and painful sting.

The red imported fire ants were first discovered in a mound in McCracken County and another colony was found several days later in Calloway County. Both are considered to be isolated cases and do not appear to be related, said Lee Townsend, University of Kentucky Extension Entomologist.

"These appear to be very small, focused infestations that have been treated and we are watching for any signs of any others," he said.

This is the first time the ants have been found in Kentucky. The ants are not native to the United States but are believed to have arrived by ship in the early 1900s in Mobile, Ala., and have been moving out across the southern United States since then. They are known to exist as far north as southern Tennessee.

Fire ants react aggressively if disturbed. Stomping on the ground near a mound will result in the ants boiling out of the mound and their sting is quite painful. The site of the sting can blister and there can be a mark on the skin for several weeks, Townsend said.

The ants actually grab the skin with their mouthparts, anchoring themselves, then they sting. Each ant can sting multiple times. Townsend said the stings are like being stuck with a hot needle.

Because of their aggressiveness, the ants will attack people, pets and other animals if their mounds are disturbed. When disturbed, the ants will often relocate their mounds which can make them difficult to treat.

The two locations where the ants were found have been treated and will continue to be inspected as well as areas around these locations. Townsend said letters have also been sent to lawn care companies in the Purchase area asking for them to be on the watch as well.

In states where there are large infestations of the ants, quarantines are in place. Counties under quarantine are as close to Kentucky as southern Tennessee.

Quarantines are issued by the U.S. Department of Agriculture and establish guidelines that any shipments out of the infested area must meet. Items affected include nursery stock, sod, hay, earth moving equipment or anything that may have loose or compacted dirt on it. It is unclear how the ants arrived in Kentucky.

There are effective treatments both in direct treatments to mounds and baits, Townsend said. These controls are especially effective when the ants are only in isolated areas.

A number of ants, such as the larger yellow ant, are swarming now and people are likely to see them and think they are fire ants when they are not.

The easiest way to identify the ants is by their aggressiveness. Their mounds aren't easily distinguishable from other ants but the way they boil out when disturbed is quite distinctive. Anyone who believes they have fire ants can put them in alcohol and take them to their county Extension office.

Texas A & M University has a web site dedicated to fire ants. To access it, go to http://fireant.tamu.edu