Remarkably Discerning

Another venerable word, recently in the news, may have religious roots:

The original quarantine, dating back to the medieval era, actually lasted 40 days, and that history is embedded in the word itself. It comes to English from Old Italian “quarantina,” originally from “quadraginta,” the Latin word for the number 40.

In the 14th century, as the bubonic plague ravaged Europe, cities took extreme measures to limit the epidemic....

Historians are unsure why 40 days became the standard European length for a quarantine, giving it its name. While the rationale was tied to observations for how long it took for infected people to die from the plague, it may have had more religious underpinnings.

Forty-day periods show up throughout the Old and New Testaments: from the length of the Great Flood, to Moses’ stay on Mount Sinai, to the time that Jesus spent fasting in the desert. The latter is commemorated in the 40 days of Lent, and the same time period has been used for other expressions of penance and asceticism.

In fact, the first known appearance of “quarantine” in English (from around 1470, according to the Oxford English Dictionary) refers to the place where Jesus is believed to have fasted. In the 16th century, it could mean the 40 days in which a widow was allowed to reside in her late husband’s house.

The use of “quarantine” for infectious diseases made it into English by the time of the Great Plague of London in 1665.

The recommended waiting period for people who may have been exposed to Ebola is 21 days; if symptoms don't appear within that period, the quarantine can be lifted.

If one does have the disease, the quarantine can last much longer. Ebola can be transmitted for weeks, even past death. WHO:

Burial ceremonies in which mourners have direct contact with the body of the deceased person can also play a role in the transmission of Ebola.

People remain infectious as long as their blood and body fluids, including semen and breast milk, contain the virus. Men who have recovered from the disease can still transmit the virus through their semen for up to 7 weeks after recovery from illness.

Considering that micro-organisms weren't observed until the 17th century, and that they weren't established as one source of disease until the 19th, the ancients who developed the rules of quarantine were remarkably discerning.