Pacific Research Section, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Department of Hygiene and Epidemiology, University of Athens Medical School, P.O. Box 1680, Honolulu, Hawaii 96806, 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 ⩾30 years of age was 36% and 13%, respectively. In contrast, only 4% of persons ⩽29 years of age had Naples antibodies and all were negative to Sicilian. These serologic data confirm previous clinical observations that sandfly fever became 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.