It was a truism among 19th-century physicians that, in the words of German epidemiologist August Hirsch, “[t]he history of typhus … is the history of human misery.” … An 1836 outbreak of typhus in Philadelphia led to important changes in how physicians understood the disease, with important lessons for epidemiology in the age of COVID-19.
During the 1800s in the United States doctors had relatively few chances to witness true epidemic typhus firsthand, and historical references to “typhus” could refer to any number of afflictions, further muddying the historical record of how pervasive the disease was.
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In departing from the common wisdom of his era, [American doctor William Wood] Gerhard attributed the spread of disease to physical proximity rather than moral corruption, laying the groundwork for new approaches to epidemiology.
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Gerhard and his colleagues did not know that typhus spreads through body lice, but they recognized anecdotally that proximity to patients put them at risk of contracting the disease. …
“Social distancing” as a phrase did not exist in Gerhard’s time, but the concept was well-established. For centuries, leper colonies and lazarettos had sequestered bodies and cargos suspected of carrying disease. …Gerhard’s somewhat more expansive definition of contagion, which included transmission through bodily fluids like sweat, alerted him to the potential dangers of being in close proximity with someone suffering from typhus.