Fire ant bites

Fire ant bites

Five species of fire ants are found in the United States. Particular concern has centered on the imported species, Solenopsis invicta and Solenopsis richteri, which are much more aggressive than native fire ants. Imported fire ants have become widely distributed in the southeastern and south central United States. They have become the most common stinging ants in North America. They are currently found in southern states from Texas to North Carolina.

The venom of the imported fire ant contains an alkaloid component that has cytotoxic, hemolytic, bactericidal and insecticidal properties. The ant bites its victim by securing itself to the skin with its mandibles, causing pain. Then, using its head as a pivot, the ant swings the abdomen in an arc, repeatedly stinging the victim with an abdominal stinger. Between 0.04 and 0.11 [micro]L of venom is injected with each sting.

The venom produces an immediate wheal and flare reaction, followed within a few hours by the development of a papule and, later, a vesicle. Within 24 hours, a characteristic pustule on an erythematous base develops. In the absence of secondary infection, this pustule resolves in three to ten days, leaving a superficial scar. Severe secondary infection and a range of allergic reactions have been reported. Treatment is generally directed at relief of symptoms and prevention of complications.

While the aggression of imported fire ants in defending their mounds against intruders is well known, Diaz and colleagues report a case of fire ants invading a building and attacking a woman who was sleeping. The patient was an elderly woman with senile dementia who was found in bed with thousands of ants crawling on her. She suffered at least 10,000 stings and required hospitalization. However, no serious complications developed, and she returned home after observation and rehydration, antihistamine and antibiotic therapy.

This case is indicative of continued clinical problems imposed by imported fire ants. Health care providers should become aware of the diagnosis, prevention, morbidity and treatment of such bites. (Southern Medical Journal, June 1989, vol. 82, p. 775.)

COPYRIGHT 1990 American Academy of Family Physicians

COPYRIGHT 2004 Gale Group