Obama issued Executive Order 13674, July 31, 2014, revising the list of Quarantinable Communicable Diseases to include common respiratory disease such as pneumonia. It also provides for the quarantining of healthy persons who may have been exposed to such diseases.
The E.O. as it appears on the Whitehouse website:
http://www.whitehouse.gov/the-press-office/2014/07/31/executive-order-revised-list-quarantinable-communicable-diseases
As the E.O. appears in the Federal Register:
http://www.gpo.gov/fdsys/pkg/FR-2014-08-06/pdf/2014-18682.pdf