By Barbara Liston

ORLANDO, Fla., Dec 6 (Reuters) - A Florida researcher is preparing to test massive dust storms in the upper atmosphere that roll in from Africa to see whether pathogens raining down on the state could be responsible for plant, animal or human disease.

University of Florida aerobiologist Andrew Schuerger said his air sampling device mounted under the wing of an F-104 Starfighter jet is the first capable of capturing particles directly from the clouds which drop 50 million metric tons of dust a year on U.S. soil.

"It's plausible that some of our previous notions of how pathogens have moved into or been introduced into an area might be overturned," Schuerger told Reuters on Friday.

The effort will be the most in-depth yet to test the health risks of the dust clouds which cross the Atlantic in summer, according to Scheurger. He said the goals are to identify bacterial, fungal and viral particles, look for viable pathogens not normally found in the state and model the risks.

A few previous studies of small samples collected at ground level suggest the presence of Bacillus megaterium, Serratia liquefaciens, and species of Streptomyces and Pseudomonas, all of which are potential plant or human pathogens.

But Schuerger said they never been tested to see if the suspected pathogens cause disease symptoms in susceptible hosts.

A full sampling program, in which microbes are collected at altitudes up to the maximum cloud altitude of 25,000 feet, is planned for 2014 when the dust storms hit Florida typically in July, August and September.

Test flights of device, the Dust at Altitude Recovery Technology, are underway this week and next at the Kennedy Space Center in Cape Canaveral, Florida.

The idea of health threats from the sky is not far-fetched.

Two previous studies in Great Britain and in the Caribbean point to disease transmitted by dust storms, according to Schuerger.

In 2001, U.S. Geological Survey scientist Dale Griffin linked a devastating outbreak of foot and mouth disease to an African dust storm which swept the U.K. one week earlier and within the disease's incubation period.

Other studies concluded that Aspergillus Sydowii carried in African dust clouds is responsible for outbreaks of disease in sea fan coral in the Caribbean, Schuerger said.

Future phases include similar tests of the Asian dust storm particles which roll in over the western U.S. in March, April and May.

The collection device is 7 feet long, weighs 178 pounds and can be mounted on jets or propeller planes, depending on the altitude to be sampled.

A scientist onboard opens and closes the devices doors at designated times to allow air samples to run through filters. A test flight on Tuesday collected samples at 1,000, 5,000 and 10,000 feet and at two different air speeds.