410 BACTERIA PATHOGENIC TO MAN 



which have not yet opened to the surface, and the same material will 

 give successful results when inoculated into susceptible animals. The 

 discharge from the nostrils or from an open ulcer may contain com- 

 paratively few bacilli, and these being associated with other bacteria 

 which grow more readily on the culture media than the bacillus mallei, 

 make it difficult to obtain pure cultures from such material by the 

 plate method. In that case, however, guinea-pig inoculations are 

 useful. 



Of test animals guinea-pigs and field mice are the most susceptible. 

 In guinea-pigs subcutaneous injections are followed in four or five days 

 by swelling at the point of inoculation, and a tumor with caseous con- 

 tents soon develops; then ulceration of the skin takes place, and a 

 chronic purulent ulcer is formed. The essential lesion is the granulo- 

 matous tumor, characterized by the presence of numerous lymphoid 

 and epithelioid cells, among and in which are seen the glanders bacilli. 

 The lymphatic glands become inflamed and general symptoms of infec- 

 tion are developed in from two to four weeks; the glands suppurate 

 and in males the testicles are involved; finally purulent inflammation 

 of the joints occur, and death ensues from exhaustion. The formation 

 of the specific ulcers upon the nasal mucous membrane, which char- 

 acterizes the disease in the horse, is rarely seen when guinea-pigs are 

 inoculated. In these the process is often prolonged, or remains local- 

 ized on the skin. They succumb more rapidly to intraperitoneal injec- 

 tion, usually in from eight to ten days, and in males the testicles are 

 invariably affected. 



MODE OF SPREAD. Glanders occur as a natural infection only in 

 horses and asses; the disease is occasionally communicated to man by 

 contact with affected animals, usually by inoculation on an abraded 

 surface of the skin. The contagion may also be received on the mucous 

 membrane. Infection has sometimes been produced in bacteriological 

 laboratories. In man, an acute and chronic form of glanders may be 

 recognized, and an acute and a chronic form of farcy. The disease is 

 fatal in about 60 per cent, of the cases. It is transmissible also from 

 man to man. Washerwomen have been infected from the clothes of 

 a patient. The infective material exists in the secretions of the nose, 

 in the pus of glanders nodules, and frequently in the blood; it may 

 occasionally be found in the secretions of glands not yet affected, as in 

 the urine, milk, and saliva, and also in the foetus of diseased animals 

 (Bonome). From recent observations it appears that glanders is by no 

 means an uncommon disease among horses, particularly in southern 

 countries, sometimes taking a mild course and remaining latent for a 

 considerable time. Horses apparently healthy, therefore, may possibly 

 spread the disease. 



Attenuation of virulence occurs in cultures which have been kept 

 for some time, and inoculations with such cultures may give a negative 

 result, or, when considerable quantities are injected, may produce a 

 fatal result at a later date than is usual when small amounts of a recent 

 culture are injected. 



