HONG KONG ANNUAL REPORT, 1953
division of the urban area into health districts was revised. There were formerly 5 health areas containing 168 districts with an average of 600 floors to a district. The ultimate aim is to have one Health Inspector in charge of 2 health districts, or 1,200 floors: this aim will not be realized until 1955, when sufficient additional inspectors have been recruited, trained and employed. For the present, a system has been adopted of appointing a special reporting inspector to each of the 7 areas. to deal with complaints and requests from members of the public.
Investigations are continuing into methods of improving the nightsoil collection service. Over half the houses in the urban area have no flush systems, and nightsoil is collected from these houses in buckets, which are then carried manually and by conservancy lorry to the nightsoil barges. An experi- mental vehicle has been designed which combines a large nightsoil collection closed tank with machinery for washing and disinfecting buckets; it is hoped that this vehicle may serve to reduce many of the obvious disadvantages of the present system.
In the sphere of pest control, progress has been made in two fields of particular difficulty. House flies,
House flies, resistant to gamma BHC have been controlled by careful alternate use of pyrethrins (to eliminate resistant strains), and control of cockroaches has been facilitated by the introduction of spot- spraying with dieldrin solution. Investigations have been started with a view to the control of biting midges, minute insects which cause great annoyance in the spring and summer. A point of interest is that, although these midges have been previously recorded as Culicoides edwardsi (a European species), over 50 specimens recently identified at the Commonwealth Institute of Entomology, London, were all found to
to be Lasiohelea stimulans de Meij.-a species apparently not before known to attack man.
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