Officials have emphasized that people are only infectious if they have symptoms of Ebola. There is no risk of transmission from people who have been exposed to the virus but are not yet showing symptoms. You are not likely to catch Ebola just by being in proximity to someone who has the virus. It is not spread through the air like the flu or respiratory viruses such as SARS.
Instead, Ebola spreads through direct contact with bodily fluids. If an infected person’s blood or vomit gets in another person’s eyes, nose or mouth, the infection may be transmitted. In the current outbreak, most new cases are occurring among people who have been taking care of sick relatives or who have prepared an infected body for burial.
Health care workers are at high risk, especially if they have not been properly equipped with protective gear or correctly trained to use and decontaminate it.
The virus can survive on surfaces, so any object contaminated with bodily fluids, like a latex glove or a hypodermic needle, may spread the disease.
How does the disease progress?
Symptoms usually begin about eight to 10 days after exposure to the virus, but can appear as late as 21 days after exposure, according to the C.D.C. At first, it seems much like the flu: a headache, fever and aches and pains. Sometimes there is also a rash. Diarrhea and vomiting follow.
Then, in about half of the cases, Ebola takes a severe turn, causing victims to hemorrhage. They may vomit blood or pass it in urine, or bleed under the skin or from their eyes or mouths. But bleeding is not usually what kills patients. Rather, blood vessels deep in the body begin leaking fluid, causing blood pressure to plummet so low that the heart, kidneys, liver and other organs begin to fail.