CLAYTON, N.C. — Fire ants are quickly spreading through the state and in isolated areas of the Triangle. Their sting is painful, especially for those hypersensitive to their venom.

They may look like any other ant, but when disturbed, fire ants act like ants on steroids.

"You can take a stick and put it in the mound, they're going to come up that stick and try to get you," said Lawrence Mudge of Bayer insecticides.

The sting can be painful.

Mudge gets stung in the name of research. He helps develop pesticides for the Bayer Company at a Clayton research facility.

"A newly mated queen can fly onto your property and set up shop," he said of the ants' march into the area.

They also spread hitching rides on turf sod and ornamental plants. Colonies can be found on golf courses and otherwise well-manicured landscapes.

"Children and pets are most susceptible to fire ants because they typically don't know what to look for," said Bayer researcher Bryan Gooch.

Fire ant mounds do not have entrance holes. Left undisturbed, they stay mostly below ground spreading and creating new sites.

"You may treat one mound, but you may not see three other mounds that are going to be a problem in a couple of weeks," Mudge said,

There are several fire ant killers on the market, including some available only through lawn care and pest control professionals.

Some products treat single mounds, while others treat entire lawns and prevent future mounds for an entire year.

Some people just cannot afford to let fire ants take over.

"Up to 10 to 15 percent of people that are stung can develop severe localized reactions from fire ant venom," Gooch said.

In rare cases, even death can occur.

Fire ants are native to South America, where certain flies and anteaters keep their population in check. They first appeared in the United States more than 70 years ago.