Another theory is that the initial illness may have created an autoimmune reaction, causing the body's immune system to attack normal cells as if they were foreign substances.

CNN: Post-polio syndrome

Looking at firefighter heart attack deaths nationwide over a decade, the researchers found that the risk of heart attack is highest when firefighters are working at a fire scene with increased odds ranging from 10 to 100 times the normal risk of heart attack.

MSN: Firefighters' heart attack risk soars at the scene

During each turn under normal conditions creatures can either attack or move to another available position on the board.

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Professor Baker said that a panic attack was essentially a normal response to fear triggered at an inappropriate moment.

BBC: Panic attack gene breakthrough

He adds that the definition of "normal" changed for Oklahomans after the attack.

CNN: A flashback to Oklahoma City bombing

Mail delivery will be suspended Thursday and Friday in the wake of the suspected ricin attack, he said, with normal delivery resuming Monday.

WSJ: Ricin Scare Upends Capital

The vaccine stimulates the body's immune system to attack cells with the mutation, leaving normal cells unharmed.

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