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Bureau of Disease Control

Fire Ants

What are fire ants?

The red imported fire ant (RIFA), Solenopsis invicta Buren, was accidentally introduced into Alabama the 1930’s. Since that time they have spread throughout the Southeast and even to California. They are prevalent in South Carolina, and are found in all 46 counties in the state.

Fire ants are aggressive and will attack anything that disturbs them. They grab with their jaws and sting with their back stinger, which contains venom. When a nest is disturbed, hundreds of worker ants can attack at the same time. The stings are painful and a victim usually will get numerous stings. Scratching the resulting pustule can lead to secondary infections.

Fire ants have been known to invade buildings, making control of fire ant mounds near homes and other buildings very important.

What are the symptoms?

Symptoms of a fire ant sting include burning and itching, a blister at the sting site and then a white pustule that forms a day or two after the sting. As long as the pustule is not broken, it may disappear within 72 hours. Scratching the pustule may lead to a secondary infection, which can be more serious than the sting.

For most people, fire ant stings are mild irritants. However, about 1 person out of 200 is seriously allergic to fire ant stings and the stings of other insects including bees, wasps, and yellow jackets. People who have had a serious allergic reaction in the past are very likely to have another serious reaction if stung again. Symptoms of a serious allergic reaction include hives, swelling of the face, difficulty breathing. Nausea, severe sweating, dizziness and chest pain. Death may occur if rapid treatment is not available.

How are fire ant stings treated?

If the only symptoms are itching, burning, a blister and the development of pustules, over-thecounter products for insect bites and stings will most likely provide some relief. You should also clean the site of the sting with soap and water to help prevent secondary infection. Elevating the site and applying ice will help reduce swelling and reduce pain if necessary.

People with serious allergic reactions to fire ant stings need to go to an Emergency Room for immediate care.

How frequent are fire ants stings?

In a survey conducted by Clemson University in 1998/99, 46% of the respondents currently had a RIFA problem, and 59% of the households had previous problems. This means that most homes in the state have had at least one experience with fire ant stings. In infested areas, fire ant stings occur more often than bee, wasp, hornet or yellow jacket stings.

What can be done to prevent fire ant stings?

The best practice is to treat fire ant mounds with insecticide. When gardening or doing other yard work, wear closed toed shoes and gloves. Young children and visitors from outside the Southeastern US should be alerted to the dangers of fire ants. Fire ants form distinctive mounds. Any mounds found in gardens, lawns or near buildings should be treated with an insecticide. About 3 gallons of boiling water poured on a mound will eliminate about 60% of the ants, but extreme care must be taken to prevent burns.

Why are fire ants of special concern in times of flooding?

A flooded fire ant colony will cling together and float until it strikes a solid object. When the colony hits high land, a tree or a building, the ants expand out and organize new mounds. During times of high water or soaked ground, the usual treatment for fire ants are not practical. People should be alert for fire ants during clean up from a disaster and wear protective clothing.