The author summarizes the information given by 13 governments-Afghanistan, Burma, Ceylon, China, India, Indonesia, Malaya, Netherlands New Guinea, Philippines, Portuguese India, Sarawak, Thailand, and Viet Nam-on their existing and proposed malaria-control programmes in response to a questionnaire prepared by WHO for discussion at the First Asian Malaria Conference, which was held in Bangkok in September 1953.Although in late 1953 nearly 46.5 million of the 271 million people living in malarious regions were protected against the disease, more than 224 million others were still unprotected.It is noted that residual-insecticide spraying-the basis of most campaigns-has significantly reduced spleen- and parasite-rates; that the minor opposition to spraying initially encountered in some places quickly disappeared as the benefits became apparent; that malaria control has resulted in general improvements in public health and has promoted socio-economic development; that anopheline resistance to the insecticides used has not been observed; that ten governments voiced the need for indoctrination of public officials concerning malaria control; and that there is a trend among governments to make financial provision for long-term malaria-control schemes.
In certain areas of Sabah, East Malaysia, local houses are frequently built without walls or with incomplete walls. Also, the people in these areas often refuse permission for their houses to be sprayed inside with insecticide (DDT). These special conditions are the reason for the persistence of malaria transmission under a WHO malaria eradication programme.Field trials were conducted in specially constructed huts, similar to the local houses, in which all-night collections of mosquitos were made, both those biting human baits and those resting on walls, in order to determine (1) the effectiveness of spraying DDT in houses without, or with incomplete, walls; and (2) the best way to protect people against mosquito bites with DDT-spraying where the house-owners have refused indoor spraying.The results indicate that (1) as expected, DDT-spraying inside a hut with incomplete walls is less effective than in a hut with complete walls, especially 6 months or more after spraying; (2) external spraying of walls with DDT at double the normal dose (i.e., 4 g/m(2)) greatly reduced contacts between man and mosquito and thereby limited transmission of malaria.