1.   When inhaled, fumes of burning poison ivy may cause dangerous swelling in the throat or lungs.

2.   In addition to the seven deaths, dozens more were infected by the virus, which can cause encephalitis, a dangerous swelling of the brain.

3.   The FDA application was withdrawn because some patients in clinical trials developed a dangerous swelling in the face.

4.   The West Nile virus can cause encephalitis, a dangerous swelling of the brain which can be deadly.