Q&As; on Transmission

What are body fluids?

Ebola virus has been detected in blood and many body fluids. Body fluids include saliva, mucus, vomit, feces, sweat, tears, breast milk, urine, semen, and vaginal fluids.

What does “direct contact” mean?

Direct contact means that body fluids (including but not limited to blood, saliva, mucus, vomit, urine, or feces) from an infected person (alive or dead) have touched someone’s eyes, nose, or mouth or an open cut, wound, or abrasion.

Can Ebola be spread by coughing or sneezing?

There is no evidence indicating that Ebola virus is spread by coughing or sneezing. Ebola virus is transmitted through direct contact with infected blood or body fluids; the virus is not transmitted through the air (like measles virus). However, droplets (e.g., splashes or sprays) of respiratory or other secretions from a person who is sick with Ebola could be infectious, and therefore certain precautions (called standard, contact, and droplet precautions) are recommended for use in healthcare settings to prevent the transmission of Ebola virus from patients sick with Ebola to healthcare personnel and other patients or family members.

How long does Ebola live outside the body?

Ebola is killed with hospital-grade disinfectants (such as household bleach). Ebola on dry surfaces, such as doorknobs and countertops, can survive for several hours; however, virus in body fluids (such as blood) can survive up to several days at room temperature.

Are patients who recover from Ebola immune for life? Can they get it again – the same or a different strain?

Recovery from Ebola depends on good supportive care and the patient’s immune response. Evidence from previous Ebola outbreaks shows that people who survived the disease had antibodies to the virus that could still be detected 10 years after recovery. We don’t know if people who recover are immune for life or if they can become infected with a different species of Ebola.

Some viruses, including Ebola, can linger for some time after recovery in parts of the body (for example, testes, eyes, spinal column fluid) not easily reached by the immune system. CDC and other researchers continue to study this issue and will share information as it becomes available.

Can Ebola stay in body fluids even after someone recovers?

Scientists know that Ebola virus can stay in some body fluids even after recovery. Ebola has been found in the semen of some men who have recovered from Ebola, and Ebola virus can stay in breast milk for some time after recovery. Ebola virus has also been isolated from the ocular fluid of a recovered Ebola patient.

It is not known how long the virus might be found in these fluids, but CDC and partners are working together to study how long the virus persists in various body fluids among Ebola survivors. They are also conducting viability testing to determine if the disease can be transmitted through these fluids.

The number of survivors from this Ebola outbreak is greater than previous outbreaks. This gives us the chance to understand how the disease affects people who have recovered, and how to advise survivors on ways to protect themselves and their communities. As CDC learns more about Ebola, we will continue to update our guidance.

If someone survives Ebola, can he or she still spread the virus?

Some viruses, including Ebola, can linger for some time after recovery in parts of the body (for example, testes, eyes, spinal column fluid) not easily reached by the immune system. It is possible that Ebola could be spread through sex or other contact with semen. Because it is not known how long Ebola might be found in the semen of male survivors, they should abstain or use a condom for all sexual activity.

There is no known risk of getting Ebola through casual contact with an Ebola survivor. We do not yet know if those who have the virus in certain parts of the body (such as the eyes or spinal column) pose any risk of spreading the virus to others, including healthcare providers, through invasive surgical procedures. CDC and other researchers continue to study this issue and will share information as it becomes available.

Did CDC know that Ebola could reappear in survivors?

Many viruses have long-term effects; some are similar and some differ from the original disease.  A large body of research exists for many viruses and other pathogens that cause illness, but not Ebola.  Because there are now many more Ebola survivors than ever before, we can learn more about the longer term effects of Ebola. We are aware of the possible risk of sustained presence of Ebola virus in body fluids after recovery, which we are thoroughly investigating. Ebola virus has been found in the semen of some men who have recovered from Ebola, and scientists know the Ebola virus can be found in breast milk even after recovery. Ebola virus also has been isolated from the ocular (eye) fluid of a recovered Ebola patient, and it is possible that the virus can linger in the spinal column fluid.

What is the virus persistence study for Ebola?

The Sierra Leone Ministry of Health, CDC, and the World Health Organization are working together to determine how long Ebola virus persists or stays in various body fluids of Ebola survivors.  We are conducting a “Virus Persistence Study,” which includes testing of body fluids in male and female Ebola survivors to determine how long the virus stays in specific fluids after recovery from the disease. The study is also conducting viability testing to determine if the disease can be transmitted through specific body fluids. 

The pilot phase of this study is testing the persistence of Ebola virus in the semen of 100 male Ebola survivors in Freetown, Sierra Leone.  So far, the study found that Ebola can remain in the semen for up to at least 9 months. Previous studies had detected Ebola virus in semen for up to 6 months. CDC is conducting further tests to determine if the virus is live and potentially infectious this long after recovery. The study also shows that the virus in semen reduces over time.

Because of the possible risk of sexual transmission, CDC advises male Ebola survivors to abstain or use condoms unless they know their semen is negative for Ebola.

Can Ebola be spread through mosquitoes?

There is no evidence that mosquitoes or other insects can transmit Ebola virus. Only mammals (for example, humans, bats, monkeys and apes) have shown the ability to spread and become infected with Ebola virus.

Can Ebola be spread through blood transfusions?

Some people in the United States who rely on blood and blood products to maintain their health have raised concerns about blood safety related to Ebola. CDC has systems in place to monitor blood safety.

Scientific evidence indicates that the virus can be passed to others from infected patients only after they start to show symptoms.

To date, there have been no reports of transfusion-transmitted Ebola in countries experiencing widespread outbreaks. However, these countries do not have systems to monitor the safety of blood products. In the United States, the Food and Drug Administration (FDA) has policies in place for whole blood donations that would result in deferral of potential donors from countries in Africa experiencing the Ebola outbreak due to the risk of malaria. In addition, plasma derived products have viral clearance steps that have been demonstrated to be effective for lipid-enveloped viruses. It is likely that Ebola virus would be inactivated by such methods used in the manufacture of plasma derivatives because it is a lipid-enveloped virus.

FDA is considering issuing guidance for blood establishments related to this issue. CDC has no recommendations at this time.

Please also see the following statements from American Association of Blood Banks and Plasma Protein Therapeutics Association.