Anopheles sacharovi

Anopheles sacharovi was the first malaria mosquito reported to develop resistance to DDT, and its changing behavior in Greece gave an early, concrete warning that chemical control could lose its effectiveness. Spraying begun in 1946 initially appeared successful. By 1949, however, the mosquitoes were resting in places the campaign had not treated; within months they could remain inside treated buildings. The sequence turns resistance from an abstract possibility into an unfolding contest between a control method and the insect’s capacity to survive it.

First Reported Resistance

The account identifies Anopheles sacharovi in Greece as the first malaria mosquito to develop resistance to DDT. This specific case appears amid a broader account of insecticide resistance spreading across mosquito populations and regions. Its importance lies not only in the appearance of resistance, but in the observable stages through which it became apparent: a shift in resting sites, followed by the mosquitoes’ return to treated interiors.

The Greek episode begins with extensive spraying in 1946 and early success. By 1949, observers noticed adult mosquitoes resting in large numbers beneath road bridges, even though they were absent from houses and stables that had been treated. The contrast between the treated buildings and the occupied bridges made the apparent success less secure: mosquitoes had not simply vanished, but were concentrated where the poison had not reached them.

A Change in Where Mosquitoes Rest

The mosquitoes’ outside resting places expanded beyond road bridges. The same behavior appeared in caves, outbuildings, and culverts, and among the foliage and trunks of orange trees. These varied refuges shared a practical advantage in the narrative of the episode: they lay outside the treated interiors where the spraying had first been directed.

The account presents this movement as an apparent response to growing tolerance of DDT. Adult mosquitoes could escape sprayed buildings, rest and recover in the open, and thereby avoid the immediate effects of treatment. The sequence matters: the early absence of mosquitoes from houses and stables was not evidence that spraying had solved the problem if adults had shifted to untreated shelter nearby.

Return to Treated Buildings

A few months after the outside-resting behavior was observed, the mosquitoes were again found inside houses, resting on treated walls. This was a further change from their earlier avoidance of treated buildings. The account describes them as sufficiently tolerant of DDT to remain on those walls, making the treated interior no longer an effective barrier.

The progression from bridges and other outdoor refuges to treated walls gives the Greek case its force. At first the mosquitoes seemed to evade exposure by leaving treated places; later they could remain where the insecticide had been applied. The change did not merely relocate the problem. It signaled that the method’s protective distinction between treated and untreated space was breaking down.

Warning of a Wider Problem

The return to treated walls is described as a portent of the serious situation that followed. The book places this observation within a wider rise in resistance among mosquitoes of the anophelene group, presenting the development as rapid and alarming. Anopheles sacharovi’s Greek history thus serves as an early instance in a larger account of resistance, rather than an isolated oddity.

The episode also complicates the meaning of early success. Spraying in 1946 initially worked, but that result did not remain stable: by 1949 the mosquitoes were resting beyond the buildings, and only months later they were found on the treated walls themselves. The narrative’s emphasis falls on this changing relationship between insect and control measure. A chemical campaign could produce an initial result while simultaneously confronting an insect population whose behavior and tolerance undermined the campaign’s continuing effectiveness.