In the aftermath of the Second World War, millions of displaced persons crowded into refugee camps across Europe where louse infestation led to outbreaks of louse-borne relapsing fever caused by Borrelia recurrentis. The conditions in the liberated concentration camps and refugee settlements were catastrophic, and lice were found in virtually every survivor. Allied forces used DDT to delouse prisoners and refugees — one of the first large-scale applications of chemical insecticide in a humanitarian crisis.

The Holocaust survivors who wrote poetry and memoir — Paul Celan, Primo Levi, Nelly Sachs — all experienced or described conditions in which lice were a daily torment. Primo Levi's If This Is a Man contains harrowing descriptions of louse infestation as part of the systematic dehumanisation of camp life. Paul Celan's 'Death Fugue,' the defining poem of Holocaust literature, emerges from a world in which the body louse was as constant a presence as death itself, and the poem's imagery of degradation and destruction carries this biological horror within it.