For the first time, scientists have identified fresh produce as the source of an outbreak of human Yersinia pseudotuberculosis infections, according to an article published in the March 1 issue of The Journal of Infectious Diseases, now available online. The outbreak was identified in Finland and traced epidemiologically to farms producing lettuce. Y. pseudotuberculosis, first identified in 1883, causes infections characterized by fever and abdominal pain that are often confused with acute appendicitis. The microbe is well known in veterinary medicine as the cause of illnesses in hares, deer, and sheep, among other animals. Y. pseudotuberculosis infections in humans are relatively rare, and while foodborne transmission has long been suspected, attempts to trace the pathogen to a concrete source of contamination in the past have been unsuccessful.