372
Epizootic Plague.
With special reference to Epimuic Plague.
Throughout the past year, the examination of rats, found dead, or caught alive, has been systematically carried out.
(a.) Total No. of Victoria rats examined,
:7
Kowloon
27
Total No. of Hongkong rats examined,
(b.) Total No. of Victoria rats found infected,
57
Kowloon
"
.22,449
8,439
.30,888
942
508
Total No. of Hongkong rates found infected,..................................1,450
Comparing these results with those of the year 1904, one finds that there is an increase in the number of rats caught by 8,981. This figure, notwithstanding the presence of a mild outbreak of plague, is very satisfactory. It shows that "rat catching" is receiving more and more support from the general public. Although a mild epidemic of plague occurred during the past year, the amount of the epizootic was considerable, the epimnic being represented by 1.450 cases, compared with 993 cases during the year 1904.
From the results obtained during the past four years, it would appear that the amount of Rat Plague, instead of diminishing, is gradually increasing. The following figures are interesting:
1902,
1903,
1904,
1905,
Year.
No. of Rats Examined.
No. of Rats found infected.
Percentage found infected.
117,839
2,015
1.7%
101,056
3,744
3.7%
21,907
993
4.5%
30,$88
1.450
4.7%
In addition to rats a number of other animals, sick or found dead, have been examined for the presence or absence of plague.
11 Fowls.
3 Cats,....
2 Ducks,
2 Geese,
1 Monkey,
.All Negative.
21
1:
カラ
31
The role played by the rat in the dissemination of plague infection would appear to be gaining gradually more recognition. The continuous observations of the epimuic during the past four years, and its relation to the epidemic, has led me to believe, that, in the rat we have the fons et origo of plague infection. In 1905, although the amount of available material is small, the epizootic preceded the first cases of plague which occurred in man. Judging from my experience of former years, such a preliminary epimuic must be looked for in every endemic plague centre previous to the appearance of widespread human plague.
Again, the experience gained in Hongkong is, that the area of the epimuic is practically co-extensive with that of the epidemic, and a diminution of the former is co-incident with a fall of the latter.
The publication of my Report on Epidemic and Epizootic Plague in 1904, setting forth the important role played by rats in disseminating plague, has evoked considerable discussion both locally and elsewhere. The criticism offered has, in my opinion, been fair, and I have anxiously awaited the results of investigators in other parts of the world, who have had ample opportunities of verifying or refuting the Rat Theory of Plague Epidemics.