It doesn’t get the attention of “Mad Cow” disease, but Iowa State University researchers are studying how Johne’s (YO’-neez) disease afflicts livestock and costs producers billions of dollars. Jesse Hostetter, a veterinary pathologist at I-S-U, explains what the disease does.It causes a chronic diarrheal disease that causes weight loss and a production loss. Johne’s disease is of prime concern in beef and dairy cattle, but it also can affect deer, sheep and goats. Hostetter says he’s studying how the bacteria survives in the host and manages to evade the host’s defenses. They hope to be able to come up with a treatment.Hostetter says a safe vaccine may be years away. Researchers in the I-S-U College of Veterinary Medicine are also developing an early diagnosis test for Johne’s disease.It’s hard to detect an animal that’s infected because the disease may lay quiet for months or even years. One estimate finds the disease causes more than one-and-a-half billion dollars in losses in the U-S each year, costing cattle producers between 40 and 230-dollars per cow.