Iowa State University Veterinarian Records, RS 22/6/0/9, University Archives, Special Collections Department, Iowa State University, http://www.add.lib.iastate.edu/spcl/arch/rgrp/22-6-0-9.html
There is little doubt but that the condition known as edema disease of pigs has been observed in Iowa since 1947. It may have been present even earlier. Records of the Iowa Veterinary Diagnostic Laboratory show that two pigs which were submitted for examination in June of that year were undoubtedly affected with edema disease. Since the condition was entirely unknown to the laboratory staff at that time, the recorded diagnosis of the case was anaphylaxis. The gross lesions which were noted and recorded at the time of autopsy, however, includes the finding of a severe edematous infiltration of the stomach wall.
Bennett, P. C.
Iowa State University Veterinarian: Vol. 13
, Article 8.
Available at: http://lib.dr.iastate.edu/iowastate_veterinarian/vol13/iss3/8