338 ACUTE GENERAL INFECTIOUS DISEASES 



Occurrence. — ^The disease is widespread and occurs in prac- 

 tically all breeding districts. Foals and calves are most com- 

 monly affected. Like the dysentery of sucklings, with which 

 it is closely related, it often appears as an enzootic, attacking 

 large ninnbers of young animals, and, as it is generally fatal, 

 seriously interferes with breeding operations. 



Etiology. — In calves the Bacterium septicum and the colon 

 bacillus, acting jointly, are accused. In colts various pus 

 cocci (staphylococci and streptococci) have been found in the 

 organs, blood and joints. It is very probable that several 

 pathogenic microorganisms are related etiologically to the 

 disease. 



Natural Infection. — Extra-uterine. — Via the navel cord which 

 has not yet become dried and shrivelled and still contains the 

 Whartonian gelatin. The danger of infection is probably 

 greatly enhanced by ligation as is usually practised in animals. 

 Naturally, filthy bedding or floors or ground covered with 

 manure, urine or the discharges from the infected navel of 

 a developed case of the disease increase the danger. It 

 happens, therefore, that a sporadic case can spread the 

 infection until every colt or calf born on the premises becomes 

 a victim. 



Intra-uterine Infection. — As some animals are born with the 

 disease (symptoms at birth; pathological lesions present too 

 old to have developed since birth), an infection in utero from 

 the pregnant dam, in whose blood pathogenic bacteria have 

 appeared, is assumed. 



A further possibility would be the permanent infection of 

 the uterus of the dam and the passage of the bacteria from it 

 to the placenta and fetus. This would explain those cases 

 where a given mare bears year after year colts which are 

 born with the disease. In cases of antepartum infection the 

 navel is usually intact. 



Necropsy. — ^The postmortem lesions vary, depending on 

 whether the case was peracute, acute, or chronic. 



(a) Peracute. — ^There are no marked lesions except those 

 of a general septic infection, such as cloudy swelling of the 

 parenchymatous organs, petechise and ecchymoses in the 

 serous and mucous membranes and acute swelling of the 

 lymph glands. 



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