A majority of Americans believe the Ebola virus can be spread by sneezing or coughing and more than a third fear that they or someone in their immediate family may contract the deadly disease in the next year, according to a Harvard University poll.

Some 85 percent of people who responded to the Harvard School of Public Health/SSRS poll said they thought the disease spread through sneezing or coughing, despite the fact that the World Health Organization regards that type of transmission as unlikely.

The spread of the disease to nurses in Dallas who treated the first Ebola patient diagnosed in the United States likely raised Americans' concerns about how the virus is transmitted, said Gillian SteelFisher, a Harvard researcher.

"The fact that Ebola has spread in this context raises questions for people," SteelFisher said in an interview. "There is a lot of uncertainty about how Ebola is being spread in the public and they are basically saying they believe it is likely to be spread in any way that seems logical to them, without knowing the mechanics of contagion."

The poll of 1,004 U.S. adults was conducted Oct. 8-12, a period that includes the disclosure of the fact that a Texas nurse was infected with the disease but before Wednesday's revelation that a second nurse had been diagnosed with Ebola.

Ebola is transmitted through contact with the blood or other bodily fluids of a person who is sick with the disease and manifesting symptoms, according to public health officials.

Despite the death of the man the nurses were treating, some 80 percent of respondents said they believed someone in their community was likely to survive Ebola if they received immediate medical care. The poll has a margin of error of 3.6 percentage points.

Some 38 percent of respondents said they are concerned that they or an immediate family member may fall ill with Ebola over the coming year, up from 26 percent who expressed that concern in an August poll.