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Title: The value of measures for the prevention of the spread of plague by railway traffic in India, together with a brief description of what experience has demonstrated to be the most satisfactory way of organising such measures
Author: Jennings, William Ernest
Awarding Body: University of Edinburgh
Current Institution: University of Edinburgh
Date of Award: 1903
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Abstract:
From a survey of the epidemiological factors which have an aetiological bearing in plague, it would seem to be thoroughly established that plague infectivity as between human beings, and the infectivity of clothing or other personal effects are agencies of very great importance. With regard to the first of these, the extent to which the factor is operative, in individual cases, is necessarily in direct proportion to the degree of opportunity afforded for the escape, from the infected body, of the infective agent. The chances of such escape are limited in cases in which, the organism has not entered the blood stream, or has not infected the respiratory passages, or has not, in primary bubonic cases, gained entrance by a ous surface. Thus, ordinary uncomplicated bubonic cases resulting from skin inoculation are only infective to a slight extent, while the socalled septicaemic cases, pneumonic cases, and uncomplicated bubonic cases in which the point of inoculation is on a mucous surface, are so in a much higher degree. Taking plague cases, generally, in such conditions as obtain in good houses, or places like plague hospitals, where circumstances favouring desiccation are encouraged, chemical disinfectants freely used, and other precautions adopted, the factor does not play an important part in the spread of plague; but the reverse is the case when the escape of the virus takes place under circumstances which are favourable for the preservation of its vitality. As, moreover, such escape may continue to occur for long periods after the establishment of convalescence, as demonstrated by Cayley, l Gotschlich, and others, it is not difficult to estimate how important a focus of infection even one case may become under suitable circumstances. It is apt to be considered that rapidly fatal cases, though of highly infectious types, do not contribute in an important degree to the spread; but it must not be overlooked that enormous numbers of bacilli may escape from such, before death, into surroundings calculated to preserve their vitality and promote their proliferation. As regards the infectivity of infected clothing or other personal effects, there are numerous instances on record which demonstrate that importation, of infected clothing by people (themselves not infected) has given rise to epidemics in un-infected places, starting by rats becoming infected in the houses into which the infected clothing had first been introduced. Besides such particular instances, it has been common experience that plague has continued to occur) among people after evacuation from infected villages' or towns in cases in which their effects had not first been disinfected, and has ceased to occur after thorough and wholesale disinfection. It is also apparent, as far as railway traffic is concerned, that infection is carried less in the persons of travellers, than in their effects, seeing that though the spread occurs chiefly along the railway routes, the numbers of cases detected at inspection posts have been very small in comparison with the numbers of persons travelling. There can, therefore, be no doubt that this is a powerful factor in plague dissemination, especially as fabrics of a porous texture folded away in boxes or bags may retain the infection for a very considerable time on account of difficulty of access', of desiccating factors. It is true that experimental attempts to isolate the virus from probably infected clothing has been attended with practically uniformly negative results; but this is in all probability due to its association with contaminating micro -organisms rendering its separation very difficult by any known method. Artificially introduced on to any fabric, and exposed to the ordinary atmospheric conditions obtaining in Bombay in the dry season, it dies within a week by the influence of desiccation. At lower temperatures, however, even when exposed to desiccating factors, it is capable of surviving for considerable periods. Forster, Loffler, and Gladin recovered it from silk, wool, and cotton respectively after forty-five, fifty-six, and seventy-six days' exposure, under ordinary atmospheric conditions, to a temperature of from 180 to 250 C. The Indian Plague Commission recovered it, under similar conditions after seventy days, and the German Plague Commissions after twenty-eight days. It is very obvious, therefore, that measures for the arrest of travelling foci of infection in the persons of plague cases, and in infected clothing are powerfully indicated as means for preventing the spread of plague by railway passengers. Experience, however, has shown that it is not possible to organize and maintain such without the of concessions which might defeat their purpose; or to bring them to such a state of perfection that all possible means of evading them could be obviated, without practically closing the channels of daily communication and paralysing trade. It is apt to be advanced, therefore, that, as they cannot be made absolute, their utility could never be expected to be commensurate with the expenditure and labour involved in organising and maintaining them. I would, however, strongly submit, as the result of personal experience extending over six years, that, if palliative measures be sufficiently rigorous to deter the infected, and probably infected, from travelling, and those from infected districts from carrying obviously contaminated baggage, they are of the greatest value in limiting the spread of plague; and I shall endeavour, in the course of this thesis to illustrate this fact from the published results of the measures as carried out in the Bombay Presidency under my supervision. Before proceeding to do this, I shall give a brief description of what experience has indicated to be the most satisfactory method of organising such measures; and shall conclude the work by an enumeration of the principal features of the plague bacillus for facilitating recognition, and a summary of the leading points which aid in the diagnosis of doubtful cases among passengers detained under observation.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (M.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.735053  DOI: Not available
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