814 PATHOGENIC MICROORGANISMS 



The onset is usually sudden, with high fever and the general 

 symptoms of a severe toxemia. Castellani states the bacilli can 

 be found in blood cultures in about 30 per cent of the cases. 



The disease may take a considerable number of forms which 

 depend very largely upon the virulence with which the organisms 

 overwhelm the body. It may be relatively mild, or may take an 

 acute septicemic form which is rapidly fatal. 



The pneumonic type is very severe and apt to kill rapidly. The 

 onset of the pneumonic type according to Strong and Teague is 

 abrupt, without prodromal symptoms. There is often a chill, head- 

 ache, and fever which reaches 103 or 104 within a day of the 

 onset, accompanied by a very rapid pulse. Cough appears within 

 twenty-four hours. The expectoration soon becomes abundant and 

 consists of blood-tinged mucus. When later it becomes thick and 

 bright red, it contains enormous numbers of plague bacilli. There 

 are marked signs of cardiac involvement, and delirium and coma, 

 frequently appear. The same observers state that plague bacilli 

 may frequently be found in the blood in such numbers that simple 

 microscopical examination suffices for their detection. They state 

 that in the Manchurian epidemic not a single case in which bac- 

 teriological diagnosis was complete, was known to have recovered. 



The pathology of the lungs in this condition consists of general 

 engorgement and edema. There are hemorrhages under the pleura, 

 often fresh fibrinous pleurisy, and if a case lasts long enough there 

 may be pneumonic infiltration. The distribution of the pneumonic 

 areas may be cither lobar or lobular. Bacteria are found in enormous 

 numbers in the peribronchial lymph spaces and in the adjoining 

 alveoli. They may also be present in large numbers in the inter- 

 lobular septa and under the pleura. 



Epidemiology. Owing to the frequency and wide-spread nature 

 of plague epidemics in the history of the world from most ancient 

 times, it is quite impossible to more than very briefly outline the 

 epidemiology of the disease. For fuller treatment of the epi- 

 demiological aspects the reader is referred to such books as 

 Rosenau's 14 Preventive Medicine and Castellani and ChalmerV 5 work 

 on tropical medicine. The prevalence of the disease in ancient times 



Rosenau, Preventive Medicine and Hygiene, D. Appleton & Co., N. Y. & 

 London, 1921. 



15 Castellani and Chalmers, Manual of Tropical Medicine, William Wood & Co., 

 N. Y., 1919. 



