In the entomological assessment of the results of malaria eradication operations a distinction should be drawn between parameters of epidemiological significance and those of merely ecological interest. The epidemiological parameters are those of the mosquito’s vectorial capacity, since they chiefly determine the level of the malaria reproduction rate whether in the absence or presence of vector control measures: the incidence of vector infections per case per day, the expectation of infective life of the infected mosquito, and the frequency of bites on man per mosquito. Observation of these factors should receive high priority, as they are the measurements required to place the entomologist in a position to advise the public health authorities as to the planning, assessment, duration, and supplementation or modification of the attack measures directed at the vectors of malaria.

However, there are many technical difficulties in the way of confident evaluation of these factors even where a localized field study can be pursued continuously. They include difficulties of sampling and of interpretation. All the available mosquito sampling methods are biased, so it is necessary constantly to cross check the results of one method by applying another. Research on additional methods, not subject to the same bias, is urgently needed. Moreover the variance in the parameters to be measured is so great that many sets of field data have had to be disregarded for lack of sufficient replication. The problems of interpreting the data to yield the epidemiological indices required arise from our persisting ignorance of aspects of the biology of many malaria vectors.

Although malaria eradication strategy depends primarily on vector control, entomology continues to be treated as a poor relation to the other malaria eradication services. It is employed only on an extremely modest scale, and the handful of scientists involved may be required to undergo little or no special training in the epidemiological aspects of vector populations. This might be corrected after field research shall have yielded a better understanding of vector biology and better operational tools for the quantitative study of the populations to be controlled. Meanwhile, the progress of many national programs is hampered, and the success of some is jeopardized by lack of sufficient technical knowledge.