Examining trends in epidemic typhus using historical texts.

Abstract

Although associated with conflict, epidemic typhus was endemic across Europe into the modern period. The extent of the problem it caused is uncertain as record keeping for those socio-economic groups most affected was rare. Google's Ngram Viewer details the frequency of word usage in written language over time. The objective was to examine whether use of the word typhus reflected potential patterns in epidemic typhus. The frequency the word 'typhus' was used in British English was studied between 1800 and 2019 and trends examined. Clear differences in word usage were apparent; use increased throughout the 19th century corresponding to increasing industrialisation. Peaks coinciding with WW1 and WW2 were apparent. Strong correlations with the words 'conflict', 'warfare' and 'industry' were seen. Mean shifts corresponded to public health legislation in the UK and the introduction of antibiotics. The study illustrates how examination of word usage can illuminate aspects of disease occurrence where official data sources are lacking.