168
it was not so prominent in the second, and the resting in an nsual manner was resumed in the third. Mosquitoes, anophelines and culicines, were seen to fall on the floor about half-an-hour after their flights in the treated hut at or after dusk in the first two weeks after the application of the insec- ticide. This period varied in accordance with the age of the spray.
6. Confirmation of species of culicines entering a house to cause a mosquito nuisance in
rural areas,
People domiciled in the New Territories suffered badly from mosquito nuisance compared with those who lived in urban areas. C. tritaeniorhynchus, C. bitaeniorhynchus, C. whitmori, C. vishnui and, sometimes, M. uniformis are the additional species causing mosquito nuisance apart from C. fatigans and Ae. albopictus. An enormous number of the above-mentioned mosquitoes were found moribund or dead on the floor in the hut after the treatment with "Gammexane" confirming our pre- vious observation that the above species are a cause of rural mosquito nuisance.
7. The residual efficacy of Gammexane as shown by the survival rate of mosquitos caught after exposure in the treated hut.
A high mortality was recorded of anopheline mosquitoes kept under observation in holding-boxes and catching bottles. No anophelines were recorded to survive forty-eight hours through- out the period of observation.
MOSQUITO NUISANCES.
Mosquito nuisances were investigated on behalf of the Urban Council at Mt. Cameron, Mt. Nicolson, the Peak, Upper Levels, Felix Villa, Hong Kong University, Pokfulam, Aberdeen, Shouson Hill, Repulse Bay, Stanley, Shek O, North Point, Cause- way Bay, Happy Valley, Kowloon Tong, Kowloon City, Tsim Sha Tsui, Yaumati, Sham Shui Po, Hung Hom and Lai Chi Kok.
Much time had to be spent in checking the vagaries of the ever mounting and moving squatter population, who created a large number of new breeding places.
568 cases were notified by Government Hospitals and Dispensaries and 116 deaths from malaria were recorded by the Registrar of Births and Deaths during the year 1949.
14th April, 1950,
J. B. MACKIE, Malariologist.
169
ANNEXURE P.
Annual Report of the Government Laboratory
for the year 1949,
The comparative table of samples examined (Table 1)
again shows an increase over the work for the previous year.
(ii) Chemico-legal
(iv) Commercial
TABLE 1.
1049
1949
(1) Waters & Waterworks Chemicals (ii) Foods & Drugs
689
722
97
54
607
728
1,886
2,069
3,056
4,547
101
132
173
158
6,609
8,404
(v) Biochemical
(vi) Coal from Department of Supplies,
Trade & Industry
(vii) Miscellaneous from Government
Departments
(i) In addition to the routine control of the public water supply, which has shown the quality of the water to be of a uniformly high standard, a number of samples from new wells in outlying districts has been examined for the Public Works Department. Samples from waterboats supplying shipping in the harbour have been periodically checked for possible salt water contamina- tion.
(ii) Under this heading are included samples of milk for control of pasteurisation, and a number of samples in connection with minor outbreaks of food poisoning. The cause of one of these incidents was traced to the use of a mixture of tung oil and arachis oil, in mistake for arachis oil, for frying purposes.
(iii) Tables 2 & 3 give details of the variety of work under this heading. There were again no cases of homicidal poisoning, but in one murder case a revolver from which the number had been erased by filing, the file which it was alleged had been used for this purpose, and some steel filings, were examined for the Police Department.
An incident of some interest was the explosion on board the s.a. Chaksang in the harbour. (See the Annual Report of the Director of Marine.) As a result of investigations carried out in the Laboratory, in conjunction with the Police Department,
No comments yet.
Private notes are available after approval.