The 1952 outbreak of encephalitis in California; vector control aspects.

The emergency vector control measures used during the summer of 1952 were designed to supplement the normal mosquito control programs of mosquito abatement districts. The emergency measures were aimed at destruction of adult vector mosquitoes in populated areas as contrasted to normal programs which consist of elimination of breeding places or destruction of the aquatic stages of mosquitoes. Experience during 1952 clearly demonstrated the limitations of present techniques for coping with adult mosquitoes and pointed up the need for better understanding of the factors controlling survival of Culex tarsalis over the winter months, as well as the need for better methods of measuring the prospect of a large number of infected vector mosquitoes early enough in the year to permit the establishment of preventive rather than palliative measures.