Three workers with the Wichita Falls Street Department in North Texas became the victims of a vicious swarm of Africanized honey bees this past Thursday. While two of the workers were treated and quickly discharged from a nearby hospital, his co-worker required further medical attention after being stung around 1,000 times by the insect species that has earned the nickname “killer bees.”

The workers were trimming trees and mowing the lawn at the Weeks Park Tennis Center when one of the men was attacked by the aggressive swarm of honey bees. After seeing their co-worker in distress, the two employees ran over to lend assistance, but ended up coming under attack as well. Local Bee Keeper John Bouchard told News Channel 9 the vibrations of the lawn equipment most likely upset the hive. He also said the hive was biggest he has encountered all year and may have held upward of 50,000 bees.

"The first unit arrived at the scene at the Weeks Park Tennis Center and found a city worker that had been stung multiple times,” Wichita Falls Fire Department Chief John Reese told News Channel 9. “In the course of trying to find out how it happened, we found that three others were stung as well.”

According to the U.S. Department of Agriculture, Africanized honey bees were first discovered in the U.S. in 1990 just outside of Hidalgo, Texas. Although the sting of an Africanized honey bee is no more toxic than its cousin the European honey bee, they earned the nickname “killer bees” due to their aggressive nature when defending their hive.

“We always assume just regular honey bees, but in a case like this, when they are aggressive, then we assume that are Africanized Honey Bees. Not only will we use a bee killing spray, but we will also use a mixture of Class A foam that we carry on our engines.”

While the man who endured 1,000 stings was considered to be in critical condition upon leaving the scene, Wichita Falls spokesman Barry Levy told the Associated Press his condition had improved under the care of doctors at a local hospital. The Weeks Park Tennis Center was closed on Friday while Bouchard and the fire department sprayed chemicals to prevent the bees from flying or stinging.