Killer ants

Ants are capable of biting, stinging and spraying irritant chemicals. Most have only a mild effect on humans; however, a few can cause injury or sometimes even death. Like wasps, individual ants are capable of stinging multiple times.

The fire ant Solenopsis invicta is a species that is expanding in range around the world and is most often involved in medical emergencies. The species is aggressive and has a painful sting. A person typically encounters fire ants by inadvertently stepping into one of their mounds, which causes the ants to swarm up the person's legs, attacking en masse. The ants respond to pheromones that are released by the first ant to attack. The ants then swarm and immediately sting when any movement is sensed. People who are sensitive to the venom can die of anaphylaxis. In a survey of 29,300 physicians in the United States of America (in 1989), reports of 83 fatalities were obtained. Some fire ant attacks on humans confined to beds have also been noted; in some locations, fire ants can be a particular threat in medical facilities since they can have nesting colonies inside human habitations.

Apart from Solenopsis invicta and Solenopsis richteri, serious allergic reactions are known from ants belonging to 6 different subfamilies (Formicinae, Myrmeciinae, Ponerinae, Ectatomminae, Myrmicinae, and Pseudomyrmecinae) and 10 genera (Solenopsis, Formica, Myrmecia, Tetramorium, Pogonomyrmex, Pachycondyla, Odontomachus, Rhytidoponera, Pseudomyrmex, and Hypoponera).

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