TUCSON, Feb. 6 Scientists are studying whether dust clouds from deserts in Africa and Asia carry bacteria, fungus and viruses to North America.

Research shows clouds of dust contain living organisms that may transmit diseases to humans. Some researchers suggest rising childhood asthma rates in the Caribbean are due to dust from Africa, The Washington Post reported Wednesday. There is now concern that diseases such as influenza, SARS and foot-and-mouth disease in livestock could also be transmitted by transcontinental dust.

Climate expert William A. Sprigg of the University of Arizona is leading a United Nations project to track dust clouds and alert people in the path. "Until now, it's been like the tree falling in the forest," Sprigg told the Post. "Nobody heard, so nobody knew it was there."

Sprigg said someday soon forecasters will be able to accurately predict the arrival of dust clouds, allowing schools and nursing homes to take precautions, the newspaper said.