DIAGNOSIS—

It is difficult to differentiate a case of true plague in its early stages from a case of fever with benign glandular swellings or mumps. The premonitory symptoms of plague, and even the early symptoms of the first stage, may be due to many different diseases and therefore great caution is needed. It is needless to say how important it is that such diagnosis should be done with great care, specially when plague cases have to be isolated, for if a case of simple fever with benign lymphadenitis be brought in close contact with patients suffering from true plague, it is a serious matter with the former. A venereal bubo, or scrofulous enlargement of glands, or enlargement of femoral or inguinal gland due to traumatic or other causes which may be attended with fever should not be mistaken for a plague symptom. A medical man who has, however, carefully observed the facies of a few cases of true plague, and who carefully takes into consideration all other probable conditions which may be mistaken for plague, may not commit a mistake, but its probabilities are to be borne in mind. The practical lesson is, that all doubtful cases should be isolated and kept separate from cases of pronounced type. The plague bears some resemblance to typhus. Murchison says: “Plague is perhaps the typhus of warm climates, the two diseases being generated from similar causes and differing only in intensity from the effects of climate and other collateral circumstances.” In typhus there is a characteristic rush, and in plague there is bubo, but this order of things have been found in some instances to have changed, there being eruption in plague and bubo in typhus. The two diseases are, however, different and bacteriological and clinical evidence corroborate this view. Cantlie adds another disease, which he says he mistook for plague:—“On June 26th, 1894, when the plague was at its height, I saw a Parsee patient dwelling in a house in which plague existed, suffering from fever 104°(F.), dry tongue, headache, backache and large swollen glands in the left groin, which had suddenly appeared. Plague seemed the only diagnosis, and the man, much against his will, was sent to the plague hospital. In two days he came back again quite well, and on examining him I found his urine thick and milky. That night I found filaria in the man’s blood, and knew I had made a mistake in the first instance. Of course, the mistake is most likely to happen, but nevertheless it is not pleasant to think that we had subjected the man to the terrible danger of plague infection.”

PROGNOSIS.

The mortality from plague may be about 90 per cent. or more when the epidemic is at its height. In the beginning, or towards the end of the epidemic, the mortality is less, as it is the case with all other epidemic diseases. The average mortality at Bombay has been 84 per cent. and in Karachi 89 per cent. It is, therefore, more fatal than all other epidemic diseases, the mortality from cholera during the height of an epidemic being about 60 per cent.

In children and in the aged the disease is more fatal than in healthy adults. Cases in which the bubo appears early and is single, or in which there is a distinct morning remission, or less general prostration or free perspiration, or in which there is no diarrhœa, have greater chance of recovery. Rapid suppuration of the buboes indicates a favourable termination. Buboes do not suppurate as a rule until the primary fever has fallen. On the other hand, carbuncles, multiple buboes (specially on the neck), meningitis, hæmorrhages, pleurisy, pneumonia, diarrhœa, gastric irritation, cyanosis, jaundice and continued pyrexia are unfavourable signs.

MICROSCOPIC AND MACROSCOPIC APPEARANCES.

Bacilli are found in all the internal organs, notably in the spleen, in blood and in the enlarged glands.

Body does not show much emaciation; decomposition commences early. Black hæmorrhagic patches are often found on the skin. The brain and membranes are congested. Sanguinous or serous effusions are found in serous cavities. Right side of the heart is dilated and is usually found full of coagulated or liquid blood. Cardiac muscles pale. The liver is enlarged and congested. The spleen is much enlarged, soft and congested. Hæmorrhagic patches have been found in the stomach. The mesenteric glands are enlarged. Kidneys congested. Bladder is sometimes found filled with bloody urine. The buboes are sometimes found to be soft and caseous. The tissues surrounding them are infiltrated with a reddish gelatinous exudation. The whole lymphatic chain from groin to the glands of the sacral or lumbar plexus, or from the axilla and neck to the glands of the mediastinum are affected. The internal glands are found more or less enlarged, injected and infiltrated with sanguineous fluid. The lymphatic follicles and Peyer’s patches in the intestines are found swollen. Hæmorrhages are found in the mesentery.

PREVENTION.—

It is evident from what has been said that to prevent plague our efforts should be directed in two ways:—(1) To prevent the importation of germs; (2) to make the environment of a place such that the germs, even if imported, may not find suitable condition for their growth. To accomplish the first we need (a) inspection of people coming from infected places; (b) stopping importation of such articles as may carry infection with them; (c) quarantine, a word which owes its origin to the fact that, daring the epidemic of plague at Milan in 1527, patients when cured were despatched to lazarettos and detained there 40 days.