Thucydides' description of the illness that afflicted Athens in the 4thBC, in his Histories of the Peloponnesian War remains the one of the most compelling captured in history.
"As a rule, however, there was no ostensible cause; but people in good health were all of a sudden attacked by violent heats in the head, and redness and inflammation in the eyes, the inward parts, such as the throat or tongue, becoming bloody and emitting an unnatural and fetid breath. These symptoms were followed by sneezing and hoarseness, after which the pain soon reached the chest, and produced a hard cough. When it fixed in the stomach, it upset it; and discharges of bile of every kind named by physicians ensued, accompanied by very great distress."
Thucydides. The History of the Peloponnesian War (pp. 66-67). Public Domain Books. Kindle Edition.
In "A war like no other", Victor Davis Hanson provides an insight on how this plague weaken the social structure of Athens and distablised its communial solidarity leading to immediate and longterm decline. So in this age of the Coronavirus Virus there might be lessons learn from this and the more recent Spanish flu (100 years past).