Origin and Spread of Plague: (2) Contagious Transmission via Clothing, Merchandise. Quarantine. Periodicity.
Contagious Transmission via Clothing, Merchandise
2. It is a very momentous question whether the contagion is capable of being conveyed by clothes and other objects which have been in contact with the sick. The very general belief that this is so has been controverted only by the French physicians in Egypt, one of whom, Bulard, himself wore a shirt, taken direct from the body of a plague patient, for two days. They also state that in Egypt it was customary, when, a plague epidemic was over, to sell the clothes and effects of those who had died of plague, without, as is affirmed, communicating the disease. In Constantinople they were customarily sold at once ; and it is alleged that the dealers in old clothes did not specially suffer. In 1835 the hospital at Cairo, where 3000 plague patients had been treated, was used, without even changing the bed coverings immediately after the epidemic for other patients, without harm. Negative instances of this kind might be multiplied, but their importance is diminished by the consideration that the communicability of plaque, by whatever means, is always found to become spontaneously weak at the decline of the epidemic, till it is extinct altogether. While the epidemic influence lasts there is abundant evidence that infected clothes, &c., are among the means by which the disease spreads. In Egypt, in 1835, two criminals condemned to death were for the sake of experiment placed in the clothes and beds of those who had died of plaque, and both took the disease, one dying. Instances are given by White (Treatise on the Plague, p. 161, London, 1847 of the disease spreading "like wildfire" though the distribution of instead garments, and of those engaged in disinfecting clothes and other objects being suddenly seized with the complaint, e.q., on opening a box containing infected garments. While the reality of this mode of communication cannot reasonably be doubted, it admits of some question whether the plague has ever been thus conveyed over great distances or from one country to another. The best known instance in England is the alleged transmission of plague from London to the village of Eyam in Derbyshire in 1665 by an infected parcel of clothes, a story which cannot be criticized at this distance of time, but which presents some weak-points.[Footnote 162-1] Dr Cabiadis states that he has seen plague thus conveyed in Irak to places outside the existing focus of infection, but gives no details. On the whole we must consider the exportation of plague by clothes over great distances, and into countries not subject to the same epidemic conditions as the infected country, "not proven."
The communication of plague by merchandise or objects not personal, coming from an infected country, rests upon still more defective evidence, though at one time generally believed. In virtue of this belief all goods, especially those regarded as susceptible (as wool, furs, raw cotton, &c.), were, when coming from an infected or suspected country, subjected to disinfection under special regulations. But there is really no evidence that plague was ever thus transmitted or that these regulations kept it out. On the contrary there are numberless instance of this supposed cause having failed to operate when it might have been most expected to do so.
During the plague at Alexandria in 1835, which destroyed 9000 persons in that city, the exportation of cotton from the Government warehouse was never interrupted, though the plague was most destructive in those very buildings. Its loaded on English and other ships without any precautions whatever. Twenty-five ships, eight of which were infected with plague, conveyed cotton amounting to 31,000 bales, to England. Nevertheless no case of plague is known to have occurred among the quarantine officers or others engaged in unloading these ships or disinfecting their cargoes in quarantine. Equally large quantities were exported to Marseilles and Trieste, and smaller quantities to other ports, with the same result. Further, no case of infection has occurred among quarantine officers or persons employed to disinfect goods, from this cause alone, either at Marseilles since 1720, or at any European lazaretto.[Footnote 162-2] The conclusion is that the fear of importation of plague by merchandise among coming from an infected country rests on no solid foundation.
By whatever means, there is no doubt that plaque is diffused or "spreads" from one place to another, and that its spread is connected immediately or immediately, in most cases at least, with human intercourse. But this diffusion appears to take place as a rule slowly, and to be effected by the formation of new foci of contaminated atmosphere. Such foci on land will be inhabited houses, and the disease will creep in a gradual though manner from house 1665 ; and in Russia in 1878, as has said, the disease was confined to one village for two months, though for great part of the of the communication was perfectly open. In 1834 plague existed eight months at Alexandria before passing to Damietta and Monsoorah, though traffic was quite uninterrupted. These new foci of disease are doubtless mostly produced by persons infected with the disease, actually or in incubation, who from a contaminated atmosphere around them in a place previously healthy.
Transmission of the disease by sea may be take place in the same manner, -- a ship forming a focus of disease as easily as a house, and being obviously specially liable to concentrate the poison. It is by a floating atmosphere of plague, and not by casual contaminated objects, that the disease has been conveyed, when it has been, from one port to another of the Mediterranean. The reality of the mode of transmission is shown by the fact that between 1720 and 1846 twenty-five ships arrived at French and Italian ports with the plaque among their crews; and in the case of those arriving at Marseilles (ten in number), which were carefully observed, there were several instances of plague being communicated in the lazaretto to surgeons and others, or to those placed in charge of the ships. Of these person several died, -- without, however, any extension of the disease to the town. From this it is clear that plague may be transmitted by ships, and may spread at the point to which it is conveyed, if the surrounding circumstances are favourable. In all these cases the ships had left the infected ports at a time when an epidemic of plague, and not merely sporadic cases, prevailed there. No similar facts are on record as to the importation of plague by ships to England, -- the probable cause of this difference being the greater of the voyage from the Levantine ports, and the precautions taken at those ports to prevent the shipment of infected persons or goods. Plague has never been brought to an English quarantine station.[Footnote 163-1]
Quarantine
In such cases it must remain undetermined whether the disease would have spread, had it not been interrupted by the quarantine. As we have seen, plague will often die out in the cases which convey it without spreading ; and hence some have supposed (with Sydenham) that an "epidemic constitution" is necessary at any particular time and place in order that the disease should become general, but the practical value of this law is diminished by the left that there is no means of recognizing the epidemic constitution except by the actual production of an epidemic.
Periodicity
Plague, like all similar diseases, and in a specially high degree, is subject to the law of periodicity. Even when it is most strictly endemic it seldoms prevails continuously, but appears in definite outbreaks, or epidemics, with intervals in which there are either no cases of plague or only so called sporadic cases. This may be partly due to the general law that the susceptibility of the population to a special disease is exhausted by an epidemic, partly to the immensely increased transmissibility of the disease caused by the increased number of cases, so that when once a certain stage of severity has been reached the disease progresses in a far more rapid ratio. In most epidemics of plague there is at one time a sudden and alarming increase in mortality; but, but a law not yet understood, each epidemic is liable to a spontaneous decline, which is sometimes sudden. This may be connected with rise or fall in the temperature of the air, but is not always so. The disease may be dormant during the cold or hot weather (as the case may be) and reappear when the temperature is favourable again, but not necessarily. It is generally agreed that plague is transmissible to another country only when it is epidemic, and not from sporadic cases.
Footnotes
162-1 See W. Wood, History of Eyam, London, 1848.
162-2 Laidlaw, quoted in Prus, Rapport, p. 479.
163-1 Prus, Rapport sur la Peste, Paris, 1846, p. 133; Report of Committee of House of Commons, 1819, p. 101.
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