Swine-Fever. 



335 



may lie up in the most isolated corners of the sty. There 

 may or may not be a purple rash on. the skin of the ears, 

 belly and hocks, but usually there is not. Diarrhoea is generally 

 observed. The patients become more and more comatosed 

 (unconscious), and they die in about a week after infection, 

 that is to say, after two or three days' illness. Outbreaks 

 of this kind are sometimes ascribed to poisoning or 

 other causes at the start, but swine-fever should always be 

 suspected under the above circumstances when no definite 

 knowledge of poisoning or other cause for the mortality is 

 actually to hand. Usually, though not always, the virulence 

 of this class of outbreak tones down shortly after the first 

 onset, and a condition of affairs like the second class establishes 

 itself ; but not infrequently all the pigs of a fairly large estab- 

 lishment — ioo or more animals — may die off in a few weeks. 



2. Outbreaks of medium virulence may also occur, and 

 in such cases the disease runs a more chronic course, and the 

 symptoms are of a less toxic nature. One or two animals die 

 after a longer but less striking illness, and further deaths 

 continue to take place at varying intervals. The number of 

 animals found to be ill at one time varies according to the 

 facilities for direct and indirect contact in the particular 

 establishment concerned. In this -class of outbreak death 

 may occur in from ten days to three weeks after infection, 

 but many of the affected animals may recover after a con- 

 valescence of varying duration. The symptoms begin by 

 a rise of temperature to io5°-6° F. The swine go off their 

 food, suffer from continuous diarrhoea, and become very 

 much emaciated. They bury themselves in the litter, 

 and can only be made to move out with difficulty. When 

 made to move, they do so with an unsteady gait, and often 

 show signs of pain in their joints. A noticeable symptom is 

 great thirst, and affected animals may often be seen and 

 heard sucking up the drainage from the floor of a wet sty. 

 They may or may not show a purple rash on the skin of the 

 ears, belly and hocks, and it may here be remarked that 

 although a purple rash in ailing pigs should always arouse 

 suspicion of swine-fever, it is far from being a constant 

 symptom. This kind of outbreak may ultimately assume the 

 characters of the third class. 



