·M 37-
Plague.
112. For the last six years no cases of plague have been reported in Hong Kong. The disappearance of this disease not only from this Colony but from the greater part of China and its decline throughout the world are due to factors which are not understood.
113. Systematic rat-catching and periodical cleansing of houses were carried out throughout the year. Total number of rats collected was 192,251 of which 21,820 were taken alive, as compared with 175,687 and 21,976 in 1934. The number collected each year shows that there is no diminution in the rat population. All the rats collected were sent to the Public Mortuary for examination. None was found infected.
Cerebro-Spinal Fever.
114. The following table shows the monthly incidence of this disease for the last 5 years:-
Month 1931 1932 1933 1934 1935 January 2 6 15 15 10 February 3 2 39 27 16 March 9 30 69 22 April 1 111 33 53 23 May 8 26 17 25 10 June 1 16 14 15 11 July 1 9 7 11 5 August 2 7 3 1 September 1 5 13 1 October 3 November 1 5 4 7 December 1 8 14 8 6 Total 24 209 191 246 110115. The disease is most prevalent in the cold weather. It dies down when the real summer heat sets in and people sleep more out of doors at night thus lessening overcrowding. Of the 110 cases reported, 54 or 49.09% proved fatal. Ever since the severe outbreak of this disease, which occurred in 1917, a supply of serum, made at the Bacteriological Institute from the local strains of meningococcus, is kept in stock. This serum gives very good results when used early in the disease.
Diphtheria.
116. Cases of this disease occur throughout the year, but the majority of those notified occur during the cold weather of December, January and February.