Kawasaki disease afflicts about 12,000 children per year in Japan. It causes rash and a swollen tongue, and often a high fever. When severe and untreated it can cause swelling of the arteries, which can lead to aneurysms and heart attacks and death. For 40 years researchers haven't been able to find a cause, but new research shows that whatever is behind Kawasaki disease, it's blowing in from Northeast China. The disease can also be found in South Korea and the United States, where air from this region of China can reach in a relatively short period of time.