"It seems to be able to hide in some places . . . but eventually the virus does go away," McCormick said. "It can take a month or two."
Duchin noted one instance in which Ebola was found in a man's semen 61 days after infection. The man, a lab worker who contracted Ebola when stuck with a needle, recovered from illness far more severe than that which Brantly and Writebol appear to have suffered, he said.
When both aid workers do make a full recovery, they likely will have one much-envied health advantage over most people, McCormick said -- a naturally acquired immunity to Ebola.
"They absolutely build up immune resistance," he said. "If I were out there right now running the program in West Africa, I would be looking for people who are far enough out of recovery that they feel well again. Those are the people I would be training to take care of patients, because they are the least likely to become reinfected."
The epidemic continues to rage in the West African countries of Guinea, Liberia, Nigeria and Sierra Leone. A total of 1,069 deaths have been reported, according to the World Health Organization, out of 1,975 reported Ebola infections.
For more on Ebola virus, visit the U.S. Centers for Disease Control and Prevention.
SOURCES: Joseph McCormick, M.D., regional dean, University of Texas School of Public Health, Brownsville; Jeffrey Duchin, M.D., chief, Communicable Disease Epidemiology and Immunization Section at Public Health - Seattle and King County, Wash., and chair, Infectious Diseases Society of America's Public Health Committee
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