The Science Center of Iowa will host a discussion of avian flu tonight, featuring Jim Roth, Iowa State University professor of veterinary microbiology and preventive medicine. The free public event, “Café Scientifique: Avian Flu & the Path to Prevention,” is 5:30 to 7 p.m. Iowa has lost more than 25 million birds to avian flu, which has disrupted businesses in Iowa, the nation’s top egg-producer. As the spread of the disease slows, efforts to dispose of the carcasses safely continue.