CONTROL OF MURINE TYPHUS WITH DDT
In the United States, murine typhus, according to Assistant Surgeon General C. L. Williams,1 constitutes an important problem in nine states grouped in the Southeast. These states are: North Carolina, South Carolina, Georgia, Florida, Tennessee, Alabama, Mississippi, Louisiana and Texas. Ninety-two per cent of the human cases of murine typhus in the United States are reported in these nine states. Despite the rat destruction and rat-proofing programs a steady rapid increase has taken place, moving from 1,882 cases in 1940 to 5,401 in 1944. In 1944, personnel of the United States Public Health Service carried out experiments on the control of rodent ectoparasites, using DDT mixed with an inert powder to dust rat runs in buildings. Results indicated that flea indexes in buildings could be reduced by as much as 90 per cent and could be kept at a low level for about