b. Vectors with Physiological Resistance to Insecticides. Some of the most
important malaria vectors have shown physiological resistance to commonly used
insecticides. In other cases, Anopheles vector species have developed behavior
patterns that cause them to avoid lethal contact with residual insecticides. Where either
of these problems seems to be interfering with control measures, the advice of medical
entomologists should be obtained.
c. Residual Sprays. The application of an effective residual insecticide to the
inside of buildings, tents, and other mosquito-frequented shelters is highly effective for
killing adult mosquitoes.
(1) Application. The insecticide solution should be applied as a spray to
walls, ceilings, screens, and other areas where mosquitoes rest. Special attention
should be given to spraying the undersides and backs of furniture and the interiors of
closets. Applications should thoroughly wet the surface but not run off.
(2) Treatment. In a malarious area, it may be advisable to treat all buildings
in nearby towns and villages as well as buildings or tents in the military installation.
Residual treatments, when carefully applied, are effective up to three months on
surfaces protected from weather. However, to establish an effective application
schedule, a qualified representative of the Army Medical Department should be
d. Aerosol Dispensers. A self-discharging, low pressure aerosol dispenser
"bomb' (Figure 5-8) is very useful in treating all types of enclosures. Important points to
remember include these:
The aerosol does not provide any residual effect.
Seven seconds' treatment with an aerosol bomb is adequate for 1,000
cubic feet of space.
It should be carried through the area at a normal walking speed while the
material is allowed to discharge upward toward the ceiling.
Doors, windows, and vents should be closed during application and for at
least 15 minutes thereafter.