Hog Cholera still kills more hogs than any other disease but, though it is incurable, it CAN be prevented. Cholera is highly contagious and easily spread by introducing new animals into a herd, by attendants carrying the infection on shoes or clothing, by vehicles, by roving animals and birds and by food and water contamination. The number of outbreaks reported each year usually is dependent on the density of hog population and the movement of swine in that area.
Stouder, K. W.
Bulletin P: Vol. 3
, Article 1.
Available at: http://lib.dr.iastate.edu/bulletinp/vol3/iss73/1