284 SWINE PRACTICE 



of hemorrhages and change in color. This lesion is particularly notice- 

 able in the red marrow of flat bones, such as the ribs. The affected 

 bones may be practically black because of the hemorrhagic extravasate. 



Ftom the foregoing description it will be noted that the lesions of 

 the ordinary cases of hog cholera consist of parenchymatous degener- 

 ation of all parenchymatous tissue and there may be subcutaneous, 

 subserous and submucous hyperemia and hemorrhage, tumefaction, 

 hyperemia and hemorrhage of lymph-glands and spleen, all of which 

 are the general lesions characterizing the various septicemic diseases. 



Uncomplicated cholera does occur, but is probablj' the exception 

 and the lesions of hog cholera when associated with other diseases are 

 difficult to recognize. 



Symptoms. — Hog cholera is essentially an acute disease. In the 

 beginning of an outbreak of hog cholera the first animals affected die 

 so quickly that the finding of one or more dead hogs is the first evi- 

 dence of the presence of disease. The first symptom in the usual out- 

 breaks of hog cholera is rise of temperature. The febrile condition in 

 the beginning does not cause any visible manifestation and is ascer- 

 tained only by means of a thermometer. Thus an infected herd of 

 swine may in the early stages of the disease be carefully inspected and 

 passed as healthy unless temperatures are taken. Some practitioners 

 encounter serious difficulties in the immunization of swine because 

 they do not take temperatures and ascertain the condition of the swine 

 that they are immunizing. The temperature in swine affected with 

 cholera varies from 104 to 108° F. 



Soon after the rise of temperature the affected animals are inclined 

 to isolate themselves and stand with their backs arched and heads 

 down, or they may crawl under the bedding. In the beginning the ap- 

 petite is impaired; later the animals refuse all food. Vomiting is a 

 common symptom in the early stages of the disease. There is usually 

 constipation in the beginning, but this is succeeded by diarrhea. The 

 fecal discharges are frequently admixed with blood. There is usually a 

 purulent conjunctivitis; the discharges accumulate on the eyelashes 

 and frequently cause adhesion of the eyelids. There may be a limited 

 mucopurulent discharge from the nose. In the less acute cases 

 erythema of the skin may occur on the second or third day, the dis- 

 colored areas being observed on the ventral surface, especially on the 

 inner side of the thighs and are red or reddish purple in color. The 

 ears may become tumefied, due to congestion and edema. The affected 

 animals become weak as the disease progresses. They have uncertain 



