America’s Homegrown-Parasite Problem Scientists don’t know why cyclosporiasis, a tropical diarrheal disease, is spreading more and more from domestic sources. The other night, I found myself in the unenviable position of trying to cook a salad. And I mean cook a salad: I spread fresh, delicious-looking gem lettuce in a pan and watched it wilt away into a sad, heated blob. America appears to be in ...