Africanized Honey Bees (also known as "killer bees") are descendants of bees brought from Africa to Brazil in the 1950s in an attempt to improve honey production in that country. Some African queen bees accidentally escaped and began to interbreed with the local European honeybees. The resulting hybrids (AHB) have been moving north ever since and are now established in southern California.
Africanized Honeybees (AHB's) are problematic not because of their killer sting, but because of the way they respond to disturbances around their nests. AHB's respond sooner to disturbances, stay agitated and attack for a longer period of time, and follow an attack victim for longer distances than European Honeybees (EHB's). In more than 40 years of hybridization with resident European Honeybees, the AHB's behavior has not changed significantly. AHB's toxin is no more harmful or deadly than EHB's, but AHB's respond by sending most of the bees in the nest to attack. This can be thousands of bees. A victim's reaction to an AHB attack varies depending on the number of stings received, the location of the stings and any special sensitivity that may have been developed by prior exposure to bee venom. Most healthy individuals can tolerate many stings without serious effects. A victim that receives hundreds or thousands of stings may exhibit toxic effects similar to a rattlesnake bite and may even die. Stings on the mouth or throat can cause a life threatening respiratory obstruction.
AHB's and EHB's can only be distinguished by an extensive laboratory examination. So if you see or encounter a bee's nest or a swarm, stay away from it. It may be an Africanized colony. Immediately notify your county Agriculture Department. Noise and vibrations from lawn mowers, weed eaters, odor from insecticides, physical contact, or motion in close proximity to a nest may elicit a defensive response from the bees.
If you are attacked, leave the area quickly. Cover your face to protect your eyes and mouth. Get into a shelter where bees cannot enter, such as a car or house. Do not dive or go underwater. AHB's have demonstrated tremendous patience in that they will wait for a victim to surface for air and then deliver stings to the mouth area. Individual bees can only sting once. After stinging, a bee leaves the stinger and poison sac embedded in the victim. The poison emits an alarm pheromone (odor) that stimulates other bees to direct their sting in the same area of the victim's body. It is important to remove these poison sacs as they continue to pump poison into your body after it has detached from the bee. Don't pull the sac out with your fingers; that will squeeze more venom into you. The sac should be scraped out with a dull edge by dragging the edge along your skin. A credit card works well for this. Victims of multiple sting attacks need immediate medical attention.