Malaria control II project, no. 391-0472; external evaluation part II : entomological aspects, report of the external evaluation team

Special evaluation, part two of an external evaluation begun in 5/83, covers the period 5/82-9/83 and is based on site visits and interviews with project personnel. Although (according to doubtfully reliable statistics) 96% of the target number of houses were sprayed in 1983, the spraying was only 30-35% efficient. Operations were generally not guided by entomological data and safety measures were notably neglected. In almost all cases observed, insecticide was prepared near water pumps, occasionally being rinsed into the pump area, and except in Gujranwala record numbers of spraying personnel showed signs of cholinesterase poisoning. Further, houses were seldom fully sprayed, sprayers were often faulty, personnel were issued only one instead of two uniforms, eating utensils were sometimes not removed prior to spraying, and in about half the cases dried insecticide was washed away by the inhabitants. The chief causes of this poor performance were inadequate supervision of spraying personnel, resistance by the population to house spraying, and a shortage of spare parts, particularly nozzle tips. Although the project"s extensive entomological data still largely need to be organized and interpreted, studies show that the two major vectors - An. culicifacies and An. stephensi - are highly resistant to both DDT and dieldrin and have recently shown signs of resistance to organophosphates. Recommendations are to: restrict spraying to active malaria foci and to epidemiologically important structures so as to reduce the amount of insecticide used and retard the development of vector resistance; encourage more systematic surveillance of such resistance; make insecticide procurement for 1985 contingent on an indepth evaluation of 1984 spraying via surprise field visits; use malathion as the insecticide of choice until entomological data indicate a need to change; encourage the long-term use of organophosphates; upgrade insecticide handling practices and safety precautions; initiate research on non-insecticidal control methods; and require urban areas to demonstrate not an 0.5/1,000 malaria incidence but only a functional surveillance system before providing them with equipment and supplies.