Report on the outbreak of plague at Sydney [1900-1907] / by J. Ashburton Thompson, Chief Medical Officer of the Government and President of the Board of Health.
- New South Wales. Department of Public Health
- Date:
- 1900-1908
Licence: In copyright
Credit: Report on the outbreak of plague at Sydney [1900-1907] / by J. Ashburton Thompson, Chief Medical Officer of the Government and President of the Board of Health. Source: Wellcome Collection.
Provider: This material has been provided by London School of Hygiene & Tropical Medicine Library & Archives Service. The original may be consulted at London School of Hygiene & Tropical Medicine Library & Archives Service.
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![03 17. By following the direction thus pointed out, I found that the required close association between jilague-rats and man did exist in every one of the small number of cases which constituted the outbreak of a later year (12). Theie were but twelve cases, spread over the seven months March to September ; they occurred in nine buildings. In the snial central area, where the epizoiitio had begun before the first case occurred, seven of the buildings stood, yet well, or even widely, separated from each other ; the other two were situated at long distances from it, the one 6 miles towards the south, tlie other 10 miles towards the north. In the two last-mentioned neighbourhoods no plague nor any suspicion of infection had ever existed ; and the only feature by which the}' were distinguished from the rest of tlie r.ietropolitan district (save the central area) was the ascertained presence of plague-rats and of eases in the two buildings. vSo also the central area was distinguished from the rest of the metropolitan district (save the two distant neighbourhoods) solely by the presence of plague-rats and cases in man in the 7 buildings, and of plague-rats unaccompanied l)y cases at other parts of it. The link 1)}' which these three widely-separated neighbourhoods were thus connected was also definitely discovered. Materials which experience has shown to be e.^pecially dangerous in connection with the introduction of plague into clean places, namely, liay, chaflf, and corn in the one case, and gunny-bags and similar wastes to be used in paper-making in the other, had been conveyed to the two houses from premises on the central area which were ascertained to be infected with plague in their rats. This instance should not be undervalued because the number of cases to which it relates is small. In epidemiological investigations accuracy and completeness are the essentials; large numbers introduce confusion and soon render the method impracticable. As it was, the time and labour entailed by quasi-detective inquiries into the circumstances of the patients at home, at work, and at leisure, into those of the businesses with wliich they were connected, into the state of the rats on promises occupied or frequented by them, into tlie state of the neighbourhood of the premises as to rat-infectir n and as to freedom from it, and the establishment of dates by documentary evidence whenever possible, from time to time unduly taxed the attention of a staff not exclusively devoted to the investigation of plague. 18. The next point to which I would draw attention is the fact that ep'zootic plague is likely to be often overlooked. The most important of the obstacles to its easy recognition lies in its character ; there are others which attach merely to the search-condiiions. As regards its character, there is a prevalent idea that the disease is so easily and so rapidly communicated from rat to rat that large numbers must always suffer together, and that in its final stages it usually causes rats to leave the nests to which they have retired at its onset, in accordance w ith the habit of sick animals, so that they die in the open ; and thus, between the two, it is thought the presence of the epizootic cannot escape even the common observer. Both of these features have been noted, but often they are wanting, and oftener still they are indistinct. This appears not merely from my own experience, but from consideration of the evidence indirectly furnished by accounts of rat-plague in many other parts of the world in which the point is not discussed. I give my own precise evidence immediately below ; but before proceeding to recount it, I venture an opinion that the very slow rate at which recognition of the rat as the essential cause of epidemic plague has improved is due, in part at least, to prevalence of this idea and to consequently inadequate searches. If, on the one hand, observed coincidences between plague in rat and in man on the same areas have acc innilated in noteworthy proportions since 1894, and if during the last five or six years increased importance has gradually come to be assigned to the rat, on the other hand it must not be forgotten that occasional admissions of its active agency have been limited, that the infectivity of man and of the rat have lately been spoken of officially (13) almost as though they had equal importance, and that formal statements have from time to time to time been made that ejjidemic plague can occur in absence of rat-plague. The vague and unsatisfactory eliaractcr of these latter seems to have escaped notice. I will not delay to examine them, and will only observe that sometimes they are unsupported by any evidence (14), sometimes they are supported by evidence which cannot but be regarded as inadequate (15) by all who have had practical experience of the difficulties with which demonstration of rat-plague is so often surrounded, and sometimes they have been supported by references to documents which are seen not to have the meaning ascribed to them (If), 17, 18,) as soon as the originals have been consulted. 19. As a rule, plague among rats in any district is so far from ])ossessiug a devastating character that its progress is slow, long-drawn out, and even insidious. The disease picks out individual rats, affects a minority of the horde at any one time, and exhibits its activity only in comparatively small, circumscribed areas which are successively attacked. On individual premises I have occasionally found almost the whole colony dead ; but this has been exceptional, and even there the rule has been that few plague-rats and many more healthy rats have been collected during many consecutive weeks. I have already puljlished .several examples (19, 20) of this, which left little doubt of the fact ; but the evidence was not perfectly good since it was impossible (save in one of those examples) strictly to exclude repeated invasions from the generally infected neighbourhood. Nevertheless, I can show from the cases of two ships that it was probably entitled to its primd facie value ; and the chrouicity of epizootic plague (not as disease, but as epizootic) seems to me a circumstance of so much importance in relation to plans for the prevention of plague, that I shall describe them at some length. 20. The first example (21) is that of the troopship Antilleaii, which sailed from Capetown on 1st February, IfOl, after having lain repeatedly alongside in the docks at South Arm. She first touched at AUiany, Western Australia, where plague has never existed, lay there in the stream for about forty-eight hours from 20th February, and sailed again for Sydney direct after having taken in a little coal. On 22nd February cleansing of the holds was begun preparatory to arrival and the reception of troops, and during these operations about fifteen carcases of rats were discovered and cast overboard ; no definite statement as to their condition was got, but they were not dried up. She arrived at Sydnej' 2nd March, and reported one deck-hand sick ; his case was clinically plague, the disease was iden'ilied by morphological, cultural, and inoculation tests, and he died on the fifth day of illness. The rats on board were destroyed bj'sulphur fumes and, as the vessel was in ballast, no difficulty was found in completely gathering their carcases ; the total number M as less than 100. The great majority were free from disease ; more than two, but very few, were infected. In one of the two plague was identified by morphological, cultui-al, and inoculation tests, and was ascertained to be present in the other by morphological and cultural tests. At Capetown (22, 23), history of unusual mortality among the dock rats reaches back to middle of December, 1900, and the first identified plague-rat was collected there on 4th February, 1901. On 27tli Februarj', 1901, occurred the first case of the epidemic which, as is well-known, comprised 766 cases ; but inquiry revealed (in all probability) two earlier cases, of which the first dated back to 24th January. It may be taken, therefore, that the infection present on board on 2ncl March may have been active since a short time before 1st February, when the vessel sailed, but had certainly begun to take eflect before 22nd February ; yet a majority of the few rats carried were in good health, and this notwithstanding that the single stcra-room must have been a centre of attraction for all the rats. 21. The second case (24) is that of the barque Alsterschwaun, 2,500 tons, which left Buenos Aires 17th May, 1903, after having shipped a full cargo of maize in bags at Rosario, and which arrived at Sydney direct 29th .July. ^Yhen this vessel got alongside, many carcases were found beneath the hatches ; but as the latter had been specially closed tightly with some idea of saving the cargo frrm deterioration, it was supposed by the master that these rats had been stifled. Nevertheless,](https://iiif.wellcomecollection.org/image/b21354704_0443.jp2/full/800%2C/0/default.jpg)
