STILLWATER, Okla. -- Seven workers who were recently hospitalized in Tillman County were stung by Africanized "killer bees," Oklahoma State University researchers said Tuesday.

County officials said the workers were trimming trees in the town of Tipton when the bees attacked them. Researchers told Eyewitness News 5 on Tuesday that DNA tests confirmed that the feared insects have finally crossed state lines into Oklahoma.

OSU entomologist Rick Grantham said the discovery of the bees was not surprising to scientists.

"It was just a matter of how long it would be before they get here, so they're here," he said.

Now, Grantham and other experts are cautioning state residents -- especially those in southern Oklahoma -- to remain on the lookout for the potentially dangerous bees.

OSU entomology Professor Russell Wright said European honeybees and Africanized bees look almost identical but said there are some telling differences.

According to Wright, killer bees are slightly smaller and produce less honey. He also said that although killer bees don't search for people to attack, they are far more sensitive to the threat of humans than their European counterparts.

"They will literally chase you down to sting you, and instead of one European honeybee stinging you, you may have hundreds of Africanized honeybees stinging you," Wright said.

Wright said the bees can be particularly dangerous if provoked because they are relentless in their pursuit.

"They will chase you farther," he said. "Instead of chasing you 50 feet, they may chase you 200 feet as you are running, and there will be more of them -- they'll be more persistent trying to sting you."

Grantham and Wright said killer bees can take over a European honeybee hive, meaning that it will be harder to tell if a wild hive is dangerous. Both entomologists recommended that Oklahomans avoid approaching wild hives.

OSU Extension officials said they plan to alert all counties in the state about the impending killer bee problem.

5 Ways To Protect Yourself From Killer Bees:

1. Watch out if you're mowing the lawn. Bees get defensive about loud noises and can hear them from as far as a quarter-mile away.

2. Don't wear floral or citrus perfumes, and don't wear aftershave lotion when you do yard work.

3. The bees will target your head, so duck or pull your shirt over your head and run if they attack.

4. Do not jump into a pool. The bees will wait for you to surface to attack.

5. If you are stung, do not use your fingers or tweezers to remove the stinger. This could cause more venom to enter your body. Instead, use a credit card to slide the stinger out.