Epidemics of typhus fever have been associated with war and famine for several centuries. What factor was most impoant in the control of such epidemics following the end of World War II?

The infectious agent for epidemic forms of typhus fever is Rickettsia prowazekii, which is transmitted from person to person by the human body louse, Pediculus humanus corporis. Disruptions of social and economic institutions by war, famine, or natural catastrophes are associated with declining standards of personal hygiene and spread of lice. Even before social and economic recovery after World War II, epidemic typhus was controlled by mass application of DDT powder. This insecticide killed the body lice; thus, the transmission cycle was interrupted. Widespread resistance to DDT and lindane now exists, and other products such as permethrin should be used. Effective antibiotic therapy with chloramphenicol and tetracycline was not available until the early 1950s. Anopheles mosquitoes are vectors in the transmission of malaria, not typhus.