There's a key distinction that I'd like to point out. Operational safety based risks, such as experienced in direct earthworks, blasting, transport, etc., disp

There's a key distinction that I'd like to point out. Operational safety based risks, such as experienced in direct earthworks, blasting, transport, etc., disproportionately affect front-line workers. Infectious disease based risks are largely indiscriminate between front-line and managerial staff. That is, unskilled labourers and administrative, clerical, officer, etc., staff all largely face a similar threat against vector-transmitted diseases. The only option for the latter is to avoid the location or posting entirely. That may be a subtle shading, and points about the US NRL made by runarberg are well taken, but again, it seems significant. Note that tropical diseases were an issue across the Panamanian isthmus for travelers and transport workers (sailors, teamsters, railroad) who traversed the region even before the canal was built, as an overland leg in the East-to-West-coast route which avoided both the time and perils of going 'round the Cape, encircling all of South America. A railroad was opened across the isthmus in 1855. That effort cost 5-10k workers' lives itself. <https://en.wikipedia.org/wiki/Panama_Canal_Railway https://en.wikipedia.org/wiki/Panama_Canal_Railway> And, somewhat supporting your viewpoint, Adam Smith describes the career duration of workers at his time (~1750--1775): "A carpenter in London, and in some other places, is not supposed to last in his utmost vigor above eight years." -- Adam Smith, Wealth of Nations, Book 1, Chapter 8, "Of the Wages of Labour" <https://en.wikisource.org/wiki/The_Wealth_of_Nations/Book_I/Chapter_8 https://en.wikisource.org/wiki/The_Wealth_of_Nations/Book_I/...> Similarly, prior to the development of modern sanitation and hygiene (fresh water supplies, sewerage systems, regular bathing, handwashing), cities were net population sinks and relied on in-migration from surrounding countryside (often driven by limited employment and income potential there) in order to simply maintain population levels. Infectious disease deaths within cities could top 50 thousand per year in 19th century London and New York, out of populations of 1 million or fewer.