In 1944 and 1945 a 5 per cent DDT-kerosene spray was applied to the walls and ceilings of all buildings in specified areas of the Bonifica di Castel Volturno on the Italian coast just north of Naples. Results in 1944 were so promising that in 1945 a more extensive project was launched in an area of approximately 120 square miles in the Tiber Delta, where a 6.5 per cent solution of DDT in kerosene was applied once at a rate of approximately 200 milligrams per square foot to the interiors of all human habitations and animal shelters between February 27 and June 15. The objective was to determine the residual effect of the spray upon anopheline density in the absence of other control measures.
The organization of the field staff, the preparation of the insecticide and the equipment and methods employed in its application are described.
Routine searches for A. labranchiae adults and larvae in Castel Volturno and in the Tiber Delta indicated that density had been greatly reduced. A year after treatment no anopheles were found in previously sprayed buildings examined in the Delta.
In Castel Volturno a significant reduction in the parasite rate of school children occurred during the 16-month period of observation. While malaria morbidity in the Delta in 1945 was higher than in prewar years, its distribution by months showed a rapid rise to a peak in March and a continuous drop thereafter, indicating that most, if not all, of the cases reported came from infections of the previous year. The usual summer rise in incidence failed to appear.