Natural outbreaks of the Ebola virus, while severe, are typically isolated and usually affect no more than a few hundred people at a time. However, from 2014-2016, infections from this deadly virus caused more than 11,000 deaths in West Africa. During this time, several cases of Ebola virus disease were also diagnosed in other countries, including the United States, due to infected travelers from West Africa that had unknowingly harbored and incubated the virus while en-route to their respective destinations.
By the time a person infected with Ebola virus becomes symptomatic, they are typically starting to shed the virus. During an outbreak, health care workers and family members of patients are often the first to respond and provide care. In this role, they are at a high risk of becoming infected with the virus as well. Therefore, it is important to understand how we can best prevent transmission in both clinical and home settings.
Human to human transmission of the Ebola virus occurs primarily through direct contact and exposure to the blood or other bodily fluids of infected patients. However, there have been new infections that occurred without documented contact between a patient and health care provider or family member. While these cases are uncommon, it is possible that a small fraction of the cases of Ebola virus infection may be the result of exposure to small droplets or aerosols containing the virus.
Laboratory studies have shown that the Ebola virus can remain infectious outside of the body for long periods of time. The virus can survive in blood samples on various surfaces for several days, even in hot and humid conditions that would typically kill most other viruses and bacteria. In an aerosolized form, the Ebola virus can survive for over an hour. Additionally, laboratory experiments have demonstrated that inhaling small amounts of Ebola virus can be fatal [1], and there are examples of Ebola virus disease being transmitted between individuals in close proximity, even though they had never been in direct contact with each other [2].