State inspectors have found nearly 100 colonies of Africanized bees in Washington, Iron and Kane counties since January 2009, when the aggressive insects were first detected in Utah.
Colonies, initially spotted in the St. George area, have also been found in Cedar City, Parowan, LaVerkin, Beryl, Modena and Kolob, said Larry Lewis, spokesman for the Utah Department of Agriculture and Food.
To determine the extent of the migration, inspectors are continuing to monitor the three southern Utah counties. And, they're setting up traps in Kane, Garfield, Beaver, Grand and San Juan counties.
Africanized bees pose a threat to commercial beekeepers, who must periodically inspect hives to ensure that the more dominant Africianzied varieties don't infiltrate domestic colonies. Farmers and other agricultural interest depend on bees to pollinate crops and produce.
The only known attack on a Utahn occurred last August in the Iron County town of Beryl. The man, who unwittingly disturbed a hive inside an old tractor, was taken to the hospital and released the same day.
It's impossible to distinguish Africanized bees from their gentler European cousins without genetic testing, Lewis said. But Africanized bees are more aggressive in attacks, and they can pursue a victim for a quarter mile or more.
Pete Kuhlmann, with the Washington County Office of Emergency Services, said Africianized bees also can colonize in areas where hives are not normally seen.
Kuhlman advised residents to be aware of their surroundings and watch for bee activity. Also, be careful with lawn mowers and power equipment around bees because they can be agitated by the noise and vibration, he said.
Homeowners can bee-proof buildings by sealing cracks and holes, and covering vents with screening.
Officials say Africanized insects should not be called killer bees. They've been linked to 14 fatalities in the U.S. since about 1990. By comparison, there are about 200 deaths each year from motorists colliding with deer.
Run as fast as possible, and get inside a building or vehicle.
Try to cover your face and head as you run.
Once you are safely away from the bees, call 911.
Start removing stingers as soon as you're in a safe area. Stingers left in place can continue to pump venom.
For additional information, visit http://ag.utah.gov/news/africanmainpage.html.