EbolaQuarantine works against Ebola but over-use risks disaster

By Grant Hill-Cawthorne

Published 3 October 2014

Quarantine, in the form of isolation, is an important component of the response to Ebola infection. As people are infectious only once they develop symptoms, isolating them and having health-care workers use personal protective equipment significantly reduces the risk of onward transmission. While quarantine is an important weapon in our arsenal against Ebola, indiscriminate isolation is counterproductive. The World Health Organization has warned that closing country borders and banning the movement of people is detrimental to the affected countries, pushing them closer to an impending humanitarian catastrophe. Still, this didn’t stop Sierra Leone from imposing a stay-at-home curfew for all of its 6.2 million citizens for three days from 19 to 21 September. Quarantine is an excellent measure for containing infectious disease outbreaks, but its indiscriminate and widespread use will compound this epidemic with another humanitarian disaster.

A man in the United States has become the first known international traveler to be infected in the West Africa Ebola epidemic and carry the virus abroad. He is thought to have been infected in Liberia and developed symptoms six or seven days after arriving in the United States to visit family. He’s being treated in isolation in Dallas, Texas.

Quarantine, in the form of isolation, is an important component of the response to Ebola infection. As people are infectious only once they develop symptoms, isolating them and having health-care workers use personal protective equipment significantly reduces the risk of onward transmission.

The director of the U.S. Centers for Disease Control and Prevention (CDC) says the man will continue to be treated in isolation. In a process known as contact tracing, everyone he has come in contact with since he became symptomatic on 24 September will be located and monitored for twenty-one days (the maximum incubation period of the virus). Anyone who shows symptoms will also be isolated and treated.

The Ebola virus is unlikely to spread further in the United States because these measures are known to be effective. Indeed, their absence has contributed significantly to the spread of the virus in resource-poor nations of West Africa.

The benefits of quarantine
Countries have been practicing this measure against infectious diseases well before we understood what caused and transmitted infections. The earliest mention of isolating people in this way is in the books of the Old Testament, for leprosy and other skin diseases.

The word “quarantine” comes from the Italian “quaranta giorni” which simply means “forty days”. It refers to the 40-day isolation period imposed by the Great Council of the City of Ragusa (modern day Dubrovnik, Croatia) in 1377 on any visitors from areas where the Black Death was endemic. In its most basic form, quarantine is the isolation of people with a disease from unaffected people.

The measure has clear benefits; it was effective during the 2003 pandemic of SARS-coronavirus when the isolation of cases and their contacts for ten days was arguably one of the most significant interventions for containing the outbreak in only five months.

And it has frequently been used to control Ebola outbreaks. Since the virus’ first and most severe outbreak in 2000, Uganda has used quarantine measures to good effect, isolating contacts of cases for up to the twenty-one days of the viral incubation period.