| malaria along the southernmost fringe of its distribution in africa: epidemiology and control. | after more than thirty years of malaria control in northern transvaal with residual insecticides, malaria prevalence has been reduced to a low level. however, low-grade transmission of plasmodium falciparum continues, with periodic focal outbreaks after abnormally high rainfall. from october 1973 to september 1976, the operational and epidemiological factors involved in this residual transmission were studied in over 17 000 people of an area of northern transvaal. incidence surveys based on the ... | 1977 | 330017 |