Effect of insecticide spraying for malaria control on the incidence of sandfly fever in Athens, Greece.

Sera from 637 Athens residents of various age groups were examined by plaque reduction neutralization test for antibodies against Naples and Sicilian Phlebotomus fever viruses. A marked change in the prevalence of antibodies to both agents was observed in persons born after 1946, when residual insecticide spraying for malaria control was initiated in Greece. The prevalence of Naples and Sicilian neutralizing antibodies among residents greater than or equal to 30 years of age was 36% and 13%, respectively. In contrast, only 4% of persons less than or equal to 29 years of age had Naples antibodies and all were negative to Sicilian. These serologic data confirm previous clinical observations that sandfly fever becam uncommon in Athens after initiation of the insecticide spraying program. Presumedly the spraying program was effective in reducing the Phlebotomus population to levels where virus transmission was minimal. New information on the specificity and duration of Phlebotomus fever neutralizing antibodies is also presented.