VARIOLA— POX 343 



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Diagnosis. — The peculiar character of the exanthema and 

 the typical course usually make the diagnosis easy. It would 

 hardly be confused with scab or pustulous eczema, as neither 

 of these diseases present marked prodromes and in neither 

 develop well-defined, large vesicles. 



Course. — The course is acute, usually requiring about three 

 or four weeks to pass through the different stages. Through 

 complications, cold w x eather and in run-down sheep, the course 

 may be considerably prolonged. Sheep-pox may remain in a 

 flock for several months. 



The mortality varies with the form the disease assumes. 

 While in the milder forms it may not exceed 4 per cent:, the 

 more malignant types claim fully 50 per cent, as victims. 



Treatment and Prophylaxis. — Usually a dietetic treatment is 

 all that is necessary (grass, roots, gruels). In mild weather 

 the sheep should be turned out to pasture. Severely infected 

 animals should be slaughtered. The medicinal treatment 

 (disinfectants for eyes, salts for bowels) is expectative and 

 symptomatic. Sporadic outbreaks in uninfected districts are 

 best eradicated by slaughter and proper disposition of the 

 carcasses. 



In permanently infected countries "ovination" or pro- 

 tective inoculation with sheep-pox virus has been practised 

 with varying results. The practice is dangerous in districts 

 where the disorder occurs only sporadically, as the inoculated 

 sheep can spread the disease. 



Cow-pox (Variola Vaccina). — Definition. — Cow-pox is a be- 

 nign, eruptive disease of the ox which occurs enzootically and 

 is characterized by a vesiculopustular exanthema' occurring 

 most commonly in the udders of milch cows. 



Occurrence. — Cow-pox is widely distributed. It is a fre- 

 quent disease among dairy cows, to which it is spread by 

 recently vaccinated milkers, attendants, etc. 



Etiology. — The cause is evidently an ultramicroscopic 

 organism which passes through coarse but not fine filters. 



Natural Infection. — Cow-pox is most commonly first intro- 

 duced into a healthy herd by recently vaccinated persons, 

 especially milkers who convey the virus directly to the udder 

 through the act of milking. It is also usually spread from 



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