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
Bovine leptospirosis in the United States was first recognized in 1944 and has now been reported in a total of 11 states. The indications are that the disease is widespread and as more veterinarians become acquainted with the disease it probably will be shown to be present wherever large, shifting populations of cattle exist.
Reinhard, K. R.
Iowa State University Veterinarian: Vol. 13
, Article 8.
Available at: http://lib.dr.iastate.edu/iowastate_veterinarian/vol13/iss2/8