Smallpox is a contagious disease caused by a virus. Smallpox virus has been eradicated worldwide through successful vaccination and treatment programs, and now exists only as a stored virus in a few research centers. Symptoms include a severe rash (which leaves scars), fever, headache, vomiting and diarrhea.
Update Date 4/14/2015
Updated by: Kevin Berman, MD, PhD, Atlanta Center for Dermatologic Disease, Atlanta, GA. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.