Scientists think people are initially infected with Ebola virus through contact with an infected animal, such as a fruit bat or nonhuman primate. This is called a spillover event. After that, the virus spreads from person to person, potentially affecting a large number of people.
The virus spreads through direct contact (such as through broken skin or mucous membranes in the eyes, nose, or mouth) with:
- Blood or body fluids (urine, saliva, sweat, feces, vomit, breast milk, amniotic fluid, and semen) of a person who is sick with or has died from Ebola virus disease (EVD).
- Objects (such as clothes, bedding, needles, and medical equipment) contaminated with body fluids from a person who is sick with or has died from EVD.
- Infected fruit bats or nonhuman primates (such as apes and monkeys).
- Semen from a man who recovered from EVD (through oral, vaginal, or anal sex). The virus can remain in certain body fluids (including semen) of a patient who has recovered from EVD, even if they no longer have symptoms of severe illness. There is no evidence that Ebola can be spread through sex or other contact with vaginal fluids from a woman who has had Ebola.
When people become infected with Ebola, they do not start developing signs or symptoms right away. This period between exposure to an illness and having symptoms is known as the incubation period. A person can only spread Ebola to other people after they develop signs and symptoms of Ebola.
Additionally, Ebola virus is not known to be transmitted through food. However, in certain parts of the world, Ebola virus may spread through the handling and consumption of wild animal meat or hunted wild animals infected with Ebola. There is no evidence that mosquitoes or other insects can transmit Ebola virus.
Risk
- Health workers who do not use proper infection control while caring for Ebola patients, and family and friends in close contact with Ebola patients, are at the highest risk of getting sick. Ebola can spread when people come into contact with infected blood or body fluids.
- Ebola poses little risk to travelers or the general public who have not cared for or been in close contact (within 3 feet or 1 meter) with someone sick with Ebola.
Persistence of the virus
The virus can remain in areas of the body that are immunologically privileged sites after acute infection. These are sites where viruses and pathogens, like the Ebola virus, are shielded from the survivor’s immune system, even after being cleared elsewhere in the body. These areas include the testes, interior of the eyes, placenta, and central nervous system, particularly the cerebrospinal fluid. Whether the virus is present in these body parts and for how long varies by survivor. Scientists are now studying how long the virus stays in these body fluids among Ebola survivors.
During an Ebola outbreak, the virus can spread quickly within healthcare settings (such as clinics or hospitals). Clinicians and other healthcare personnel providing care should use dedicated, preferably disposable, medical equipment. Proper cleaning and disposal of instruments such as needles and syringes are important. If instruments are not disposable, they must be sterilized before using again.
Ebola virus can survive on dry surfaces, like doorknobs and countertops for several hours; in body fluids like blood, the virus can survive up to several days at room temperature. Cleaning and disinfection should be performed using a hospital-grade disinfectant.
In the United States, hospital-grade disinfectant refers to U.S. Environmental Protection Agency (EPA)-registered hospital disinfectant pdf icon[PDF – 278KB]external icon with a label claim for a non-enveloped virus.
