198 Distemper of Dogs. 



History. The frequency of the disease among dogs, and its im- 

 portance, is well illustrated by the fact that it is known in almost all 

 languages as the "dog disease." In Europe it is supposed to have 

 occurred since the second half of the eighteenth century, having been 

 introduced from Asia (Spinola) or from Peru (Heusinger). The 

 infectious nature of the disease was proved in the middle of the last 

 century, by successful experiments of transmission, with the nasal dis- 

 charge (Eenner & Karle, Weisz, Laosson, Krajewsky), with saliva 

 (Venuta), and with the contents of the skin pustules (T?rasbot), from 

 affected animals to young dogs. Its etiology, however, was first 

 cleared up by the investigations of Carre (1905), which established that 

 the disease is caused by a filtrable virus. 



Occurrence. Distemper is a remarkably frequent disease 

 of young carnivora, especially of young dogs, so much so that 

 the great majority of the latter become affected before reaching 

 the age of one year. In kennels young animals usually become 

 affected in great numbers, but not infrequently the disease 

 occurs in an epizootic form affecting entire townships or even 

 large territories. It is more prevalent during warm weather, 

 but is also quite frequent during the winter. 



Etiology. According to the investigations of Carre which 

 have since been confirmed by Lignieres, distemper is caused 

 by a filtrable virus which in the beginning of the disease is 

 contained in the nasal discharge. 



Subcutaneous injections of two drops of the serous dis- 

 charge from the nose kills young animals within 6 or 7 days 

 with symptoms of coma and a fall of the temperature at the 

 termination of the disease. The autopsy shows only an accumu- 

 lation of clear, yellow serous fluid in the pericardium. Injec- 

 tion of a filtered nasal discharge, or of filtered pericardial 

 fluid produces a rapid rise in temperature after 3 or, 4 days, 

 catarrh of the conjunctivae and the nasal mucous membrane, 

 cough, and after 8 to 10 days a pustular exanthema on the 

 parts which are thinly covered with hair. The nasal discharge 

 becomes more profuse and purulent, whereupon death results 

 in from 2 to 3 weeks. The autopsy reveals catarrhal pneu- 

 monia, the heart muscle appears to be sprinkled with small 

 hemorrhages and yellow spots, while the pericardium, some- 

 times also the pleural and the abdominal cavity, contains a 

 serous fluid in varying quantities. The exudate is only ex- 

 ceptionally virulent, unlike that of acute cases. The blood is 

 only virulent at the beginning of the fever, while later, even 

 in an unfiltered condition, it will not produce the disease; this 

 applies also to the nasal discharge which has become purulent, 

 and to material from the hepatized lungs. Healthy dogs may 

 be artificially infected by cohabitation. 



In view of the results of the investigations, the different bacteria 

 which have been found by various investigators in the tissues of dogs 

 affected with distemper must be considered as secondary participants 



