CDC Downplays Ebola's Threat to the United States
Deadly virus relatively slow to transmit, and travel factors make spread from West Africa unlikely
Public health workers are also discussing whether to step up monitoring at airports. "The idea of whether additional border-based controls can be more effective is actively under discussion by the international community," Monroe said.
But despite these cases, the odds are extremely low that an Ebola infection could reach the United States and spread into a full-fledged outbreak, said Thomas Geisbert, an expert on the deadly virus and a professor of microbiology and immunology at the Institute for Infectious Diseases at the University of Texas Medical Branch in Galveston.
Ebola is not transmitted through the air, which makes it much harder to spread than respiratory diseases like the measles, influenza or SARS, Geisbert explained.
Instead, Ebola is spread through body fluids like blood, vomit or saliva. A person has to come into contact with those fluids to risk infection.
"Because it's not airborne, it would take very close contact with someone who is at an advanced stage of illness to become infected," Geisbert said.
It is possible for someone to be infected with Ebola but initially show no symptoms, allowing them to board a plane with no one knowing they carry the deadly virus. However, the virus can spread only if a person experiences symptoms that spread bodily fluids like vomit and blood, Geisbert noted.
"You have to be sick to shed a large amount of the virus," he said.
And even if Ebola did reach an American airport, this country is much better prepared to deal with an infectious disease than those in West Africa, he added.
"We have a very good public health infrastructure in the United States," he said. "We have isolation wards in hospitals in most parts of the country. I think it would be much easier to contain here."
Brantly tested positive for Ebola and is showing symptoms, Monroe said. A family physician from Fort Worth, Texas, Brantly has been in Liberia since October 2013. He serves as the medical director of the Monrovia case management center for Samaritan's Purse, a North Carolina-based aid agency.
A second American also has been infected with Ebola. Nancy Writebol, a hygienist working for a group allied with Samaritan's Purse, had been focused on decontaminating people who came and went from the Monrovia care center, to prevent further spread of Ebola. She has suffered a fever but showed no other symptoms, Monroe said.