The sting of fire ants can be painful and even deadly -- and the threat rises during fall across the southeastern United States.
At this time of year, fire ants move to warm surfaces such as concrete slabs or asphalt roads, according to the American College of Allergy, Asthma and Immunology (ACAAI), which urges people to take precautions.
A child can be stung walking through the yard because the colony may be traveling through the grass in search of a warm winter home.
Fire ant sting attack rates have been reported as high as 50%.
"Parents should be just as aware of fire ants in the fall as the spring, because it's dangerous for a child to step in a fire ant mound this time of the year and be stung," said Dr. J. Allen Meadows, ACAAI president. "Unlike other times of the year, you do not have to step in a mound to get a sting."
Fire ant stings are painful for most, but they can trigger life-threatening allergic reactions in some people.
People who have had an allergic reaction to a sting in the past have a 60% chance of a similar or more severe reaction if stung again.
Symptoms of a fire ant allergy can include: hives, itching and swelling in areas other than the sting site; abdominal cramping, intense nausea, vomiting or diarrhea; tightness in the chest and difficulty breathing; hoarse voice or swelling of the tongue or throat, or difficulty swallowing.
Signs of a severe allergic reaction (anaphylaxis) can include dizziness, a sharp drop in blood pressure or cardiac arrest.
In such cases, the person should get an epinephrine shot if available and seek immediate medical help.
Allergy shots can protect against life-threatening fire ant stings, according to the ACAAI.
The U.S. National Library of Medicine has more on fire ants.