A private security guard patrols the apartment building in Dallas where Ebola patient Thomas Duncan stayed. The family that hosted him is quarantined. Tom Pennington/Getty Images hide caption itoggle caption Tom Pennington/Getty Images Shots - Health News Here's How An Ebola Quarantine Works In The U.S. October 3, 2014 The family that hosted Ebola patient Thomas Duncan in Dallas is under quarantine. It's a time-honored public health tool to stop the spread of infectious disease. But it can be abused.