ENG-1959 — Page 170

PUBLIC HEALTH

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Just over 90% of all cases notified were from the unprotected areas and of these 72.6% came from the Sai Kung district in the eastern part of the New Territories. 28% of the Sai Kung notifica- tions emanated from the boat population, the remainder being scattered among the 43 small villages in the district. Of the 24 fresh cases appearing in the urban areas, none could be traced to an infection contracted locally and there was strong presumptive evidence that the infections had not originated in the protected zones. In fact no anopheline mosquitoes or larvae were recovered in these protected zones despite careful routine searches. Of the blood parasites identified 91% were P. vivax, 8% P. falciparium and 1% P. malariae.

In the Sai Kung district a pilot scheme, using prophylactic paludrine, was started in two villages towards the end of March. The paludrine was distributed weekly with the co-operation of the Village Representatives in an attempt to estimate whether or not malaria in the Sai Kung district could be reduced significantly by chemoprophylaxis. It is too early yet to assess the result and the scheme is still in progress.

Two malaria surveys were carried out, one in the urban pro- tected areas and the other in the border zone in the north of the New Territories between Lo Wu and Sha Tau Kok. The former survey was amongst children between 2 and 14 years and was carried out in co-operation with the School Health and Maternal & Child Health Services. Between April and October 1,744 children aged two to five years were examined; the spleen rate was zero. From April to June 6,676 school children aged five to fourteen years were also examined and the number with palpable spleens was 18 or 0.27%. In addition 4,033 blood smears were taken from infants under one year of age attending urban M.C.H. centres. All smears were negative for malaria.

In the border areas 907 children between the ages of two and ten years were investigated in eleven villages of whom 11 or 1.1% had palpable spleens. There were no smears positive for malaria in 1,005 blood smears taken from children under 10 years of age.

The laboratory continued to carry out routine identification and dissection of mosquitoes and the staining and examination of blood smears. Field tests were conducted in the efficacy of insecticides and the susceptibility of anophelines to insecticides, Information