684 Glanders. 



Natural infection is brouglit about through the medium of 

 the secretions of diseased animals. In diseased horses, except 

 in animals with acute glanders, in which case the entire body is 

 infected, the virus is present only in the affected organs and 

 their secretions. The nasal discharge and the secretions of the 

 cutaneous ulcers are particularly virulent, while the saliva is 

 virulent only as a result of admixture of secretions from the 

 lungs; the same may be said in regard to the feces, although 

 they may become infected from intestinal ulcers also. In 

 affection of the kidneys the urine may be virulent. Bacilli that 

 gain access to the outer world by these means, though they are 

 incapable of reproduction under ordinary conditions (obligate 

 parasites) may retain their vitality for some time, especially in 

 damp, dark places, where they are protected from drying out, 

 and may then, even after the lapse of several days, gain access 

 to the bodies of susceptible animals in a virulent condition. 



In the majority of cases infection of horses takes place 

 through the digestive tract by the ingestion of food or water 

 contaminated with the infected nasal secretions of a diseased 

 animal. The food as well as the water may also have been con- 

 taminated by infected mucus that has been coughed up out of 

 the lungs or by the secretions of cutaneous ulcers, the feces or 

 the urine. Accordingly infection is most apt to occur when 

 healthy horses feed out of the same manger or drink from the 

 same trough to which glandered horses have access. Thus, in 

 a large stud of horses, where the animals are not tied up, but are 

 all permitted to feed and drink out of the same common racks or 

 troughs, a single glandered horse may be the means of infecting 

 a large number within a very short time. Under ordinary con- 

 ditions, on the other hand, the disease usually spreads much 

 more gradually. On the range or pasture affected animals may 

 contaminate the grass with their nasal secretions, and thus 

 infect healthy horses. 



According to positive results of feeding experiments, infec- 

 tion may also take place through the intact mucous membranes ; 

 the presence of wounds or injuries of course favors the process. 

 Thus Cadeac & Malet found that horses and cats are very easily 

 infected if the \drus is rubbed into the superficially scarified 

 mucous membrane of the mouth, while the same effect is produced 

 in asses by the simultaneous administration of fodder contam- 

 inated with prickly vegetation. Catarrhal conditions of the in- 

 testinal mucous membrane also favor infection. 



Infection rarely takes place through the uninjured mucous 

 membrane of the respiratory tract. Aside from the fact that 

 primary nasal glanders is very rare, the observation that experi- 

 mental infection of the nasal mucous membrane nearly always 

 produces acute glanders argues against the theory that natural 

 infection usually takes place through the nasal mucous mem- 

 branes; glanders resulting from natural infection usually runs 

 a chronic course. Primary pulmonary glanders also evidently 



