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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![Nevertheless, the occurrence came to notice, .and it was learned that 112 carcases had been gathered and disposed of. The result of the search then carried out was collection of fifty-one rats and carcases of rats, all of which turned out lo be healthy except two, in which plague was identified by morphological, cultural, and inoculation tests. Then, after a first f'lmicatini witii sulphurous-sulphuric fumes, a further and larger number of carcases were collected and examined, among which however, plague was identified in nine only. This search was neces.sarily more or less superficial, for the cargo was s'.ill ill the holds, but after a second fumigation the barque was taken alongside, and unloading allowed to begin ; a great many more comparatively fresh carcases were afterwards turned out, but the fact of plague infection having been fully established already, further examinations were not made. Plague first appeared at Rosario (2,')) in September, 1899. The infection must have been carried aboard the barque during seventy-four days, notw ithstanding which a large majority of the rats which were exa,mined were still free from plagi'e. 22 General experience ashore, as distinguished from that derived from particular premises, was to the same effect. Thus the lent^th of the epizootic periods in each of the four years 1903-190G, reckoned from the first day to the last day on which a plague rodent was identified, was 14, 40, 47, and 49 weeks respectively. The total number of rodents examined during each of these terms was 14,671, 43,822, 28,416, and 27,731. Although there were exceptions, they may be regarded as having been all taken on the same small area of the city, and they were collected by the rat-intelligence staff in a regular way, the numbers brought in week by week having been approximately uniform. All of them were examined in the laboratories, and plague was identified in 161, 243, 141, and 174 of them. Some of these identifications were recorded almost in each week of each of the four terms ; although there were some longer intervals, they occurred quite irregularly. The small proportion of plague-rats attracts attention, and is due in part to the account having been restricted to those carcases in which the disease could be bacteriologically recognised. Other carcases were submitted which were too far advanced in putrefaction for that kind of examination, some of which may be presumed to have resulted from plague ; but their number was not large, and if rcckon(!d, would not materially disturb the proportions mentioned, and would not at all disturb the time relations. 23. This evidence show.<», 1 thir.k, that epizootic plague may pursue a chronic course, and that its long continuance mav not be attended at any stage by such a mortality as could not be easily overlooked. Indeed, the figures just quoted show that there is difficulty in proving that any of the epizootics referred to did much damage to the rat-tribe as a whole. But this difficulty owns two cause? at least. As the putrefying bodies of plague-rats arc not a cause of nuisance much more often than are those of the rats which die.from day to day in the natural course, I suppose most of Ihcm die in the nests to which they have retired on first falling ill. The other cause is the conditions which prevent dwellings and warehouses from being thoroughly searched, unless the sanitary staff has taken possession of them ; privacy and the course of business .cannot be so hampered without substantial reason. However, when whole blocks of houses have been taken in hand and systematically cleansed, no remarkable number of rats ever has been turned out. When that course has not liccn taken, then the difficulties in the way of securing plague-rats, save in small number, have lain in the fact that only lualthy rats, active in their search for food, are likely to be, and as a rule are, trapped ; yet trapping is the only means available to an intelligence staff, for systematic poisoning no more leads to discovery of carcases than does plague itself. 24. Under all these circumstances, it will be perceived, rat-plague might easily be overlooked in places where the search cannot be, or is not, systematically and thoroughly carried out, and I have no doubt that it has occasionally escaped detection in this or that isolated area at .Sydney, where the contrary was the case. It will also bo judged, probably, that elaborate rat diagrams are not worth the labour of planning, for the figures on which they are based arc necessarily inconiplet \ and largely result from incalculable chances by which even their relative value i.s vitiated. The fact is that the whole truth concerning epizootic plague cannot be learned, and he who should accei]t the greater or less number of carcases observed in c rcumscribed districts as indicating greater or less need for energetic measures would often be deceived. The best search can at most only enable the limits of the area over which the epizootic has extended to be defined, but that it can do with considerable accuracy. From all this a very important practical nde derives, namely: Discovery of a single infected carcase should be taken as peremptorily indicating the most thorough scavenging and cleansing o'f the neighbourhood in which it was found. Rarely will the labour entailed have been spent in vain. The ca.se is quite different with an imported case in man ; that, as we have already seen, calls for no action in respect of the neighbourhood. 25. Here a note on the species of Mun met with at Sydney, on their susceptibility to jdngue under natural conditions, and on the observed association of the different species with plague in man, may be usefully inserted. The species are M. decumamis, M. rathis, together with its Alexandrine variety which it is unnecessary further to mention separately, and M. musciihis. These comprise all which have become domesticated. Plague has been identified in all of them, and in such numbers as shows, I think, that the proportions of each species enumerated in any year depended rather on local distribution than on any difference in susceptibility. In the first year to which I now refer, plague was identified in 86 D., 26 R., and 49 M. ; in the second, 106 P., 73 R., and 62 M. ; in the third (26), in 78 D., 45 R., and 18 M. ; in the fourth (27), in 46 D., 89 R., and 39 M. I have found each of the two species of rats infected and associated with plague in man by itself, as well as the two together on the same premises. Infected mice have never been found alone in that association, so that I Lave nothing which points to the mouse as an efficient cause of plague in man ; on the other hand, I have not observations sufficiently extensive to show that it does not so act. In a short series of nine houses, infectc<l M. mu-sculus was once actually found alone in association with one ca.sc of plague, but rats had ai the same time died in number on the premises, although none were secured in a state which admitted of identification of the infection ; J/, decumamis ■was associated alone in a second, .1/. musculus and 3f. decumamis together in a third, all three species together in a fourth and fifth, and M. rmisr.ulus with ratlns in the remaining four. All the rats on the troopship Antillcan (see above), on which was one case of plague at arrival, while another (to which it was unnecessary to refer before) occurred in connection with cleansing of the store-room, were decumamis. All those found on the other vessel, the Alsterschwann, were ratfrm in its Alexandrine variety ; in that instance no one was infected, either among the crew or among the many persons engaged in unloading and in disinfecting her. In a rural district, 300 miles from Sydney, where twelve cases occurred in ten houses, all the rats (1,128) taken, whether in the houses or in farm-buildings or on river banks, were decumamis with three exceptions ; all the infected rats (101) were of that species, and there were two infected mice. At an important seaport 70 miles to the north of Sydney, w-here an outbreak consisting in fourteen cases occurred, plague was identified in 206 rodents out of 6,653 examined ; 171 were dccumami.i, 13 were rallus, and there were 22 mice. The association of the infected species with plague in man at this place in the eleven cases which could be so examined was dicnmamiH alone eight times, decumamis and miisculus together twice, and decumamis, raltus, and miiscidiis together once. The species found m connection with two large warehouses at Sydney where eight cases occurred -was rallus; all the patients recovered. That connected with six cases which occurred at a small hotel was also rotlus, and two of these patients died. The records might be further examined with quite similar results, but perhaps enough has now been said. After having mentioned](https://iiif.wellcomecollection.org/image/b21354704_0444.jp2/full/800%2C/0/default.jpg)
