The disease is essentially a septicemia, or blood poisoning, and the microbic invasion occurs from inoculation probably either through abrasions of the skin or by injury to the mucous membranes from coarse fodder, etc.
"Special Report on Diseases of Cattle"
U.S. Department of Agriculture J.R. Mohler
1877, Virulent microbic Diseases.
"Makers of Modern Medicine"
James J. Walsh
These simple suggestions were the result of rigid experimental demonstration of the spread of the diseases from worm to worm, including the demonstration of the microbic causes of the two diseases.
"Makers of Modern Medicine"
James J. Walsh