Scientists have developed a vaccine for the so-called "cruise ship virus" using tobacco plants.

Charles Arntzen, a plant researcher with Arizona State University, said in a statement at the American Chemical Society conference in Washington, D.C. Tuesday, that the vaccine could be administered every 12 to 18 months by a nasal-delivery system.

He said that experiments were successful in mice and he expects human trials to begin later this year or in 2010.

Arntzen and his colleagues re-engineered plant viruses to produce high levels of "virus-like" nanoparticles in tobacco plants.

He said the particles are about the same size as the norovirus that plagues many cruise ship passengers, but they contain none of the infectious material of the original virus. The particles also stimulate an immune response to fight infection, he said.

Arntzen said researchers are investigating vaccines developed from plants in the fight against many diseases, including swine and bird flu and other infectious diseases.