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jeyporiensis on both banks of the Shing Mun between Pineapple Pass and the P.W.D. Dam, also in some of the A. minimus breeding places. During the year from 150 to 200 labourers were employed by the Engineering staff on anti-malarial works—the great majority of which were engaged on operations of a permanent nature which take time to accomplish.
As well as anti-larval operations other anti-malarial measures directed against mosquitoes were undertaken. Over 33,000 Anophelines were captured in the coolie lines. Such catching could not fail to have a marked effect on the situation.
On the 20th April the provision of mosquito nets was again recommended, also on the 12th May. This was not successful as all the labourers were not provided with nets, and those which were issued were made of poor material, were of insufficient dimensions, and of faulty design being furnished with flaps and also there was insufficient accommodation for their proper arrangement. Only those which were privately owned were satisfactory.
From September onwards attempts were made to screen the lines, defects in the screening were pointed out from time to time. In spite of all this numerous Anophelines were still caught—the screening acting as a trap. A. hyrcanus which formerly had only been captured in small numbers were now obtained in such abundance as to enable a reliable natural infective index to be worked out. Table VIII gives the estimated population month by month and its distribution according to race, and the number of cases treated due to all causes, and to malaria. In considering these figures it must be taken into account that the population—especially Cantonese—was a floating one.
It will be seen that in the month of May when malaria became serious there were 40 cases out of a population of 650, or an incidence of 6.1%. In December when a considerable amount of anti-malarial work had been completed there were 64 cases out of a population of 671, or 9.5%. The blood films were taken by the Resident Medical Officer, forwarded to the Bureau, stained and examined by the Inspectors until the end of September from which time they were done by the Shing Mun Hospital staff. From September onwards the staff in charge of anti-malarial operations and of the Hospital resided on the spot in mosquito-proof houses. None contracted malaria. At the end of the year 14 Europeans were living at Shing Mun. Six of these had suffered from malaria. Two of them twice. On several occasions faults in the screening of their houses were reported. Seven policemen—5 Indians and 2 Cantonese—were in residence from 15th August onwards. One Cantonese suffered from malaria. Screening defects in the Police Barracks were also reported.