Red imported fire ants aren’t supposed to be in the United States, but these dangerous pests have made themselves at home here. If you are stung by fire ants, you’ll probably know it. They swarm onto your skin and their stings feel like fire.
Fire ants range in color from red-brown to black, and grow up to 1/4 inch in length. They build nests or mounds about 1 foot high, usually in grassy areas like lawns and pastures. Unlike most anthills, fire ant nests don't have just one entrance. The ants crawl all over the hill.
Fire ants are very aggressive when their nest is disturbed. If provoked, they swarm on the perceived intruder, anchor themselves by biting to hold the skin stable, and then sting repeatedly, injecting a toxin alkaloid venom called solenopsin. We refer to this action as “stinging.”
Fire ant nests are like small cities, sometimes containing as many as 200,000 ants, according to Texas A&M University. Inside these busy colonies, female workers maintain the nest’s structure and feed their young. Male drones breed with the queen or queens. When young queens mature in communities with more than one queen, they fly off with males to create new nests.
Red imported fire ants came to the United States by accident in the 1930s. They have thrived in the Southern states and moved north because they had no local predators. There are fire ants native to the United States, but they are not as dangerous or hard to get rid of as red fire imported ants.
Fire ants can withstand just about any challenge. Researchers at the University of Arkansas found that it would take two weeks of temperatures below 10°F (-12°C) to kill an entire colony. While fire ants kill and eat other insects like regular ants, they have also been known to live on crops and animals. Fire ants can even form nests on water and float them to dry locations.
If fire ants sting you, chances are you’ll know. They attack in swarms, racing up vertical surfaces (such as your leg) when their nests are disturbed. Each fire ant can sting several times.
To identify fire ant stings, look for groups of swollen red spots that develop a blister on the top. Stings hurt, itch, and last up to a week. Some people have dangerous allergic reactions to stings and will need to seek immediate medical help.
Treat mild sting reactions by washing the affected area with soap and water and covering it with a bandage. Applying ice can reduce the pain. Topical treatments include over-the-counter steroid creams and antihistamines to reduce pain and itch.
Texas A&M University recommends a home remedy solution of half bleach, half water. Other home remedies include diluted ammonium solution, aloe vera, or astringents like witch hazel. These remedies may offer some relief, but there is no hard evidence to support their use.
The sting and bite marks should go away in about a week. Scratching can cause the affected area to become infected, which can make sting and bite marks last longer.
Anyone can develop an allergy to fire ant stings, although people who’ve been stung before are at higher risk. An allergic reaction can be fatal. Signs of a dangerous allergic reaction include:
Symptoms develop quickly after exposure. It’s critical to get emergency medical treatment if you experience signs of an allergic reaction to a fire ant sting.
If you have a severe allergy, there are involved long-term treatments, including whole body extract immunotherapy. During this process, an allergist-immunologist injects ant extracts and venom into your skin. Over time, your sensitivity to the extracts and venom should decrease.
The best way to avoid fire ant stings is to stay away from fire ants. If you see a nest, resist the temptation to disturb it. Wear shoes and socks when working and playing outside. If you are attacked by fire ants, move away from the nest and brush the ants off with a cloth or while wearing gloves so they can’t sting your hands.
Fire ant colonies are hard to destroy. There are some poisonous baits that when applied regularly may get rid of fire ants. The most common is a pesticide called piretherine. The best time to use bait against fire ants is during the fall, when ants are less active. Professional pest control companies treat fire ants where they are common. Dousing a fire ant hill with boiling water can also be effective for killing the ants, but it is also likely to cause the survivors to attack.
Fire ants are a growing problem in the southern United States. Avoid them whenever you can, and take basic protective measures when going outside, such as wearing shoes and socks. Be on the lookout for a severe allergic reaction in anyone who has been stung, and get emergency medical help if needed.