Destruction of rats by trapping and poisoning is a commendable procedure, but of itself will never eradicate endemic plague, for the losses in the rat population are quickly made good if survivors are provided with food and harbourage. An important measure of personal prophylaxis is inoculation with anti-plague vaccine, which affords a good degree of protection.

In view of the breakout of Plague cases in the city, the following article, compiled from Encyclopaedia Britannica describing the clinical characters of the fell disease, how it is to be diagnosed and how it disseminates and what are the measures of protection will be read with interest. A.B. Patrika, 23-4-48.


One of the results of recent observation is the classification of plague cases three heads: (1) Bubonic, (2) Pneumonic and (3) Septicaemic. This classification is a clinical one, and the 2nd and 3rd varieties are just as much plague as the first. It is necessary to say this, because a misleading use of the word Bubonic has given rise to the erroneous idea that true plague is necessarily Bubonic and that non-Bubonic types are a different disease altogether.

The illness varies within the widest limit, and exhibits all gradations of severity, from a mere indisposition, which may pass almost unnoticed, to an extreme violence only equalled by the most violent form a cholera. The mild cases are always Bubonic; the other varieties are invariably severe, and almost always fatal. Incubation is generally from 4 to 6 days, but it has been observed to be as short as 36 hours and as long as 10 days (Bombay Research Committee); as a rule the onset is sudden and well marked.

(1) Bubonic cases usually constitute three fourth of the whole, and the symptoms may therefore be called typical. In a well-marked case here is usually an initial rigour-in children convulsion-followed by rise of temperature with vomiting headache, giddiness intolerance to light; pain in epigastrium, back and limbs; sleeplessness, apathy or delirium. The headache is described as splitting; delirium is of the busy type, like delirium tremens. The temperature varies greatly; it is not usually high on the first day-from 101 degrees to 103 degrees-and may even be normal, but sometimes it rises rapidly to 104 degrees or 105 degrees or 107 degrees F. A fall of 2 or 3 degrees on the 2nd or 3rd day has frequently been observed.

The eyes are red and inflamed; the tongue is somewhat swollen and first covered with a thin white fur, except at the tip and edges, but later it is dry and the fur yellow or brownish. Prostration is marked. Constipation is the rule at first, but diarrhoea may be present, and is a bad sign. A characteristic symptom in severe cases is that the patient appears dazed and stupid, is thick in speech, and staggers. The condition has often been mistaken for intoxication. There is nothing however in all these symptoms positively distinctive of plague, unless it is really prevalent.

The really pathognomonic sign is the appearance of buboes or inflamed glands, which happens early in the illness usually on the 2nd day; sometimes they are present from the outset, sometimes they cannot be detected before the 3rd day or even later. The commonest seat is the groin, and next to that the axilla; the cervical, submaxillary and femoral glands are less frequently affected. Some times the buboes are multiple and on both sides, but more commonly they are unilateral.

The pain is described as lancinating. If left, they usually suppurate and open outwards by sloughing of the skin, but they subside spontaneously or remain hard and indurated. Petechiae occur over buboes or on the abdomen but they are not very common, except in fatal cases when they appear shortly before death. Boils and carbuncles are rare.

(2) Pneumonic plague was observed and described in many of the old epidemics but its precise significance was first recognised by Childe in Bombay. He demonstrated the presence of the bacilli in the sputa, and showed that the inflammation in the lungs was set up by primary plague infection. The pneumonia is usually labular, the onset marked by a rigor, with difficult and hurried breathing, cough and expectoration. The prostration is great and the course of the illness is rapid.

The breathing becomes very hurried-40 to 60 respiration in the minute-and the face dusky. The expectoration soon becomes watery and profuse, with little whitish speaks which contain great quantities of bacilli. The temperature is high and irregular. The physical signs are those of broncho-pneumonia; oedema of the lungs soon supervene, and death occurs in three or four days.

(3) In Septicaemic cases the symptoms are those of the bubonic type but more severe and without buboes. Prostration and cerebral symptoms are particularly marked; the temperature rises rapidly and very high. The patient may die comatose within 24 hours, but more commonly death occurs on the 2nd or 3rd day. Recovery is very rare.

The average duration of fatal cases is 5 or 6 days. Patients who survive the 10th or 12th day have a good chance of recovery. Convalescence is usually prolonged. Second attacks are rare but not unknown.


When plague is prevalent in a locality, the diagnosis is easy in fairly well-marked cases of the bubonic type, but less so in the other varieties. When it is not prevalent the diagnosis is never easy, and in pneumonic and septicaemic cases it is impossible without bacteriological assistance. The earliest cases have hardly ever been even suspected at the time of any outbreak in a fresh locality.

It may be taken at first for almost any fever, but particularly typhoid, or for venereal disease, or lymphangitis. In plague countries the disease with which it is most liable to be confounded are malaria, relapsing fever and typhus, or broncho-pneumonia in pneumonic cases.


The investigations of the Indian Plague Commission working in conjunction with the advisory committee showed that Bubonic and Septicaemic plague are transmitted by the agency of fleas. Highly susceptible animals are not infected by their plague. stricken fellows so long as fleas are excluded from the cages, but with the introduction of these ectoparasites the disease forthwith spreads from the sick to the healthy.

Subsequent experience has confirmed the main findings of the Commission and outbreaks of human plague are unquestionably mere extensions of preceding or concurrent plague affecting animals. Rats are of outstanding importance and reservoirs of infection through their close association with man, but marmots, gerbilles and ground squirrels have been responsible for epidemic outbreaks in China, South Africa and California respectively.

The Plague Commission concluded that disease can be transmitted by the faeces of infected fleas, but did not state that this is the usual method of spread. It was later demonstrated that the entrance to the fleas stomach becomes obstructed by a mass of plague bacilli. Cuch fleas in their persistent efforts to feed merely succeed in distending gullet with blood which now contaminated, regurgitates on the skin of the host. The organisms then enter the body either through the fleas bite or through abrasion of the skin. Rat fleas, the dog flea, common mouse fleas, marmot fleas and the human fleas among others are proven carries of plague.

The seasonal variation in the spread of plague has been recognised for many centuries. In temperate countries epidemics attain their maximum in the summer months, whereas in tropical climate the onset of hot dry weather brings an existing epidemic to an end. In each case the peak of the plague curve coincides with meteorological conditions most favourable to the activities and longevity of fleas.

In contradistinction to the foregoing, pneumonic plague once established, spreads independently of animals and fleas. In outbreaks of ordinary plague, a secondary involvement of the lungs supervenes in small portion of cases, and if atmospheric and environmental conditions favour the survival of transmission of bacilli an epidemic of pneumonic plague may result, the virus being transmitted from the cougher to the victim upto a range of about 3 feet.


So long as members of a community are content to live in association with rats and fleas correlative plague is likely result. Meanwhile plague prophylaxis consists mainly of warfare against rats in the hope of ultimately banishing them from human habitations and from contract with man. Any general elimination of these pests over wide areas is a slow, costly and usually impracticable affair, and all that can be achieved in most cases is some degree of palliation by rat-proofing of grain stores, wharves and other places which serve as centres for the dissemination of plague.

Destruction of rats by trapping and poisoning is a commendable procedure, but of itself will never eradicate endemic plague, for the losses in the rat population are quickly made good if survivors are provided with food and harbourage. An important measure of personal prophylaxis is inoculation with anti-plague vaccine, which affords a good degree of protection.

Persons entering plague-infected house should wear gaiters, and otherwise render their closing as flea-proof as possible; if there is any suspicion of pneumonic plague, goggles and masks made of several layers of fine gauze, should be worn with out fail.

A B Parker