M 79
2. ANNUAL REPORT OF THE MALARIA BUREAU
1937.
It has been customary for some years to compile a comprehensive report on the activities of the Malaria Bureau since its inception in 1930 and such reports should be consulted by those interested in the malarial problem in Hong Kong.
2. The present report omits all references to the manifold activities of the Bureau and confines itself to new developments during 1937.
3. Some 696 (+three among the Forces of the Crown) deaths were ascribed to malaria, forming rather over two per centum of deaths registered from all causes. The corresponding figures for 1936 were 503 and just under two per centum respectively.
4. Disturbance of soil has not been found to be a factor of any great consequence in increasing the number of breeding places of the important anophelines.
5. Night catching of anophelines in pigsties and cattle-byres was continued for the purposes of obtaining material for precipitin tests and dissections.
6. Identification of the species found gave the following results:
A. minimus, A. jeyporiensis var. candidiensis, A. maculatus, A. hyrcanus var. sinensis, A. fluviatilis, A. aitkenii var. bengalensis, A. splendidus, A. karwari, A. vagus, and A. lindesayi var. japonicus.
7. The first two species are responsible for serving as vectors in the major number of cases of malaria that occur.
A. maculatus, a malaria vector greatly to be feared in Malaya, is seldom found in dwellings in Hong Kong and (judging from precipitin tests) appears to be zoophyllic rather than homophyllic. Locally it has only been found infected with malaria in the Shing Mun area. The larvae of this species were met with along with those of A. (F) togoi in rock pools by the seashore on Cheung Chau Island. Samples of the water from these pools were submitted to the Government Analyst and were found to contain 0.06%, 0.08%, 0.09%, 0.17% chlorine as chlorides.
8. A. hyrcanus was obtained in large numbers from "screened" lines at Shing Mun and Pat Heung Camps; its infection rate was, as usual, low in comparison with that of...