DIAGNOSIS 



1429 



Diagnosis. — ^This, in the bubonic type, which is commonest, is 

 based on the acute onset with high fever, great prostration, and 

 the presence of a bubo. Difficulty may arise in the diagnosis 

 between the bubonic type of plague and climatic, venereal, and 

 symptomatic buboes; between pneumonic plague and ordinary 

 pneumonia; and between septicaemic plague and various fevers. 



In venereal bubo there will be found ulcers on the genital organs, 

 or, at least, the patient will give a history of such. In climatic 

 buboes and various symptomatic buboes due to small ulcerative 

 lesions on the legs, etc., the general condition of the patient is usually 

 far from being so grave as in plague. In any doubtful case bacterio- 

 logical methods should be employed. A little of the fluid from the 

 suspected bubo is withdrawn, under aseptic precautions, by means of 

 a sterile syringe, and films are made and stained with methylene 

 blue, diluted carbol-fuchsin, or Leishman's stain. The presence of 

 bipolar staining bacilli is sufficient, for all practical purposes, to 

 diagnose the case as one of plague, though it is desirable, whenever 

 possible, to complete the investigation by cultural methods followed 

 by inoculations into animals. 



In pneumonic plague the expectoration is generally fluid and 

 greatly h.^emorrhagic, and is not purulent, as it frequently is in 

 catarrhal bronchitis or in bronchial pneumonia, nor is it tenacious, as 

 in croupous pneumonia; the examination of the sputum — instead 

 of the sputum, the lung juice, obtained by puncture with a sterile 

 syringe, may be examined — ^will reveal the presence of numerous 

 plague bacilli, easily distinguishable from the pneumococcus by 

 their being Gram-negative. 



Acute Septiccemic Plague. —The diagnosis is most difficult, as there 

 are no characteristic symptoms and no glandular enlargements. In a 

 country where plague is endemic any case of sudden high fever, with 

 extreme prostration and blood examinations negative as regards 

 malaria and relapsing fever, should be viewed with suspicion. The 

 fever is generally higher than in dengue or pappataci fevers, often 

 reaching 105° F., while the prostration is much more marked. The 

 microscopical examination of the blood ioxB. pestis is unfortunately 

 often negative, and the cultural examination requires time, and 

 hence the diagnosis may be made too late, as by that time the patient 

 maybe dead. It may be distinguished from malaria by the absence 

 of Laveran's parasites, from relapsing fever by the absence of spiro- 

 chaetes, but it is to be noted that cases of mixed infection occur. In 

 India, as observed by Polverini and others, cases of mixed infection 

 of plague and relapsing fever are not rare. The diagnosis between 

 septicsemic plague and cryptogenic septicaemias due to the pneumo- 

 coccus and other germs, as well as occasionally the differential diag- 

 nosis from pernicious malaria, typhus and typhoid, maybe impossible 

 without a complete bacteriological examination of the blood. 



The simple microscopical examination of thick films of blood (Manson-Ross 

 method) for the presence of bipolar staining bacilli is often a failure. The 

 so-called dilution method introduced by CasteUani for the search of the Bacillus 



