“The history of typhus,” wrote August Hirsch in his classic nineteenthcentury Handbook of Geographical and Historical Pathology, “is written in those dark pages of the world's story which tell of the grievous visitations of mankind by war, famine, and misery of every kind.” Besides its association with poor conditions in temperate climates, typhus fever remained mysterious even after enthusiastic applications of the germ theory had clarified the inner workings of many other diseases. By the time Nicolle adopted the disease for special attention in the first decade of the twentieth century, it had been more clearly differentiated from typhoid fever (with which it was often confused) and, for the most part, had been banished from western Europe. It did, however, continue to exist in both endemic and epidemic forms in countries near Europe’s borders.

One region that typhus continued to menace was North Africa. The epidemics in Tunisia in the 1860s had made history, as we have seen, for helping to ensure the country's bankruptcy. Still, such occurrences were subsequently rare. Typhus was endemic in neighboring Algeria but not, it seemed, in Tunisia. Indeed, in 1894, Lucien Bertholon, best known for his anthropological studies of North Africa (and for his position as head doctor to prisons in Tunisia), published a statistical study of disease distribution among French colonists in Tunisia. Although several diseases were described as presenting challenges, typhus did not even merit a mention: it was not regarded as a problem in Tunisia. Indeed, Bertholon judged the country to be relatively healthy—“une terre de colonisation par excellence.” Even the IPT's own Adrien Loir, in his subsequent listing of diseases fatal to the inhabitants of Tunis, made no mention of typhus.