306 Sheep Pox. 



which in such cases are born with pox erui)tions ; in other cases 

 the fetuses in utero remain liealthy in spite of tlie infection of 

 the mother, such lambs having developed an immunity against 

 the disease. 



■Riekert vapcinated about 700 lirpciliiig ewes in the last week of pregnaTiey. 

 Eepeated inoculations of the lambs born from these animals were ineffective, while 

 3(i lambs, from ewes which were not vaccinated, developed pox nine days after 

 the inoculation. Three years later the inoculation gave ])ositive results in the 

 first, while the latter failed to contract the disease. Anacker likewise failed to 

 produce the disease in 60, Peuch in three landjs from affected sheep. 



Other species of animals as well as man, are not susceptible 

 to sheep pox, or only in a very slight degree. Goats occasionally 

 1)ecome affected as a result of contact with sheep affected with 

 pox, and according to Borrel & Konew the sheep virus gains 

 in virulence for goats by passage through their bodies, while 

 it becomes attenuated for sheep (see p. 327). Supposed in- 

 fections of horses by affected sheep are reported by Berger & 

 Pecus. 



Anatomical Changes. The autopsy of sheep dead from 

 pox reveals, as a rule, besides the characteristic changes of 

 the skin, hemorrhagic inflammation of the mucous membrane 

 of the air passages and of the gastro-intestinal canal. On the 

 nnicous membrane of the pharynx and trachea, less frequently 

 in the abomasum, pox vesicles are occasionally present, or 

 ulcerations which have developed from them. The lungs, 

 especially near the pleurae, contain small, gray translucent 

 nodules, which may show a central caseation; these nodules are 

 located within pneumonic areas (Morel & Vallee). In the 

 other internal organs changes indicating pyemia or septicemia 

 may l)e found (acute swelling of the lymph glands, petechiae 

 on the serous membranes, parenchymatous and fatty degenera- 

 tion of the parenchymatous organs, sul)pleural infarcts in the 

 lungs, initial acute interstitial nephritis, etc.). 



Under the skin hard nodules the size of hazelnuts and 

 showing a homogenous cut surface, may occur; they consist 

 of thick masses of polynuclear leucocytes, lodged between 

 shreds of subcutaneous connective tissue, many of these 

 leucoc3^tes containing broken down nuclei. 



Symptoms. The pox exanthema is preceded by an incuba- 

 tion period of six to eight days, which is somewhat longer in 

 cold weather. After this has passed the disease commences 

 with febrile and catarrhal symptoms, which consist in dullness, 

 loss of appetite, and elevation of temperature up to 41-42°, 

 accelerated pulse and respiration; sometimes trembling and 

 chills may be also observed. Pressure on the vertebral column, 

 especially in the lumbar region, causes many of the affected 

 animals to show signs of pain. The eyelids are swollen, the 

 conjunctivae reddened, and from the narrowed slit of the eyes 

 tears mixed with mucus are discharged. From the nose there 



