Mysterious fatal strokes in 3 U.S states baffle docs

People in three southern U.S. states are facing a health threat no one can explain: an abnormally high risk of suffering a fatal stroke - even among tourists just visiting the region.

Residents and visitors alike in near-coastal areas of North and South Carolina and Georgia have a stroke risk at least 10 per cent higher than people in other U.S. states.

And when local people leave the area, even for a short trip, their risk of a fatal stroke drops.

Since short visits don't change a person's weight, blood pressure or diabetic status, researchers are literally wondering whether there's something in the local air or water.

The region takes in 153 counties, and some very popular tourist spots: Myrtle Beach, Savannah and Charleston.

So far, the evidence seems to shoot down every other explanation they've come up with.

Hot, humid climate? Florida has the same, but without the strokes.

Deep-fried, artery-clogging Southern cooking? Other Southern states have as much or more obesity, but with less stroke risk.

Attempts have also failed to account for the problem through smoking, another major risk factor for stroke, as well as through poorer health care, infectious agents, bad genes and toxins in the water or soil.

So what is killing the people of the coastal "Low Country," and their visitors?

"Nobody knows. I think if you ask any one person, they'll have some sort of theory, especially people not in the profession," said Ilan Shrira, a psychologist at the University of Florida. "You have lots of stereotypes among people who have never been to this area: diet or poverty or something. But among people who know the research... there's no evidence for any one explanation." - can