Source: Centers for Disease Control and Prevention, World Health Organization
What is Ebola virus disease?
Ebola virus disease (formerly known as Ebola haemorrhagic fever) is a severe, often fatal illness, with a death rate of up to 90%. The illness affects humans and nonhuman primates (monkeys, gorillas, and chimpanzees).
Ebola first appeared in 1976 in two simultaneous outbreaks, one in a village near the Ebola River in the Democratic Republic of Congo, and the other in a remote area of Sudan.
The origin of the virus is unknown but fruit bats (Pteropodidae) are considered the likely host of the Ebola virus, based on available evidence.
How do people become infected with the virus?
In the current outbreak in West Africa, the majority of cases in humans have occurred as a result of human-to-human transmission.
Infection occurs from direct contact through broken skin or mucous membranes with the blood, or other bodily fluids or secretions (stool, urine, saliva, semen) of infected people. Infection can also occur if broken skin or mucous membranes of a healthy person come into contact with environments that have become contaminated with an Ebola patient's infectious fluids such as soiled clothing, bed linen, or used needles.
Additional transmission has occurred in communities during funerals and burial rituals. Burial ceremonies in which mourners have direct contact with the body of the deceased person have played a role in the transmission of Ebola. Persons who have died of Ebola must be handled using strong protective clothing and gloves and must be buried immediately. WHO advises that the deceased be handled and buried by trained case management professionals, who are equipped to properly bury the dead.
People are infectious as long as their blood and secretions contain the virus. For this reason, infected patients receive close monitoring from medical professionals and receive laboratory tests to ensure the virus is no longer circulating in their systems before they return home. When the medical professionals determine it is okay for the patient to return home, they are no longer infectious and cannot infect anyone else in their communities. Men who have recovered from the illness can still spread the virus to their partner through their semen for up to 7 weeks after recovery. For this reason, it is important for men to avoid sexual intercourse for at least 7 weeks after recovery or to wear condoms if having sexual intercourse during 7 weeks after recovery.
Who is most at risk?
During an outbreak, those at higher risk of infection are:
What are typical signs and symptoms of infection?
Sudden onset of fever, intense weakness, muscle pain, headache and sore throat are typical signs and symptoms. This is followed by vomiting, diarrhea, rash, impaired kidney and liver function, and in some cases, both internal and external bleeding.
The incubation period, or the time interval from infection to onset of symptoms, is from 2 to 21 days. The patients become contagious once they begin to show symptoms. They are not contagious during the incubation period.
Ebola virus disease infections can only be confirmed through laboratory testing.
What is the treatment?
Severely ill patients require intensive supportive care. They are frequently dehydrated and need intravenous fluids or oral rehydration with solutions that contain electrolytes. There is currently no specific treatment to cure the disease.
Some patients will recover with the appropriate medical care.
To help control further spread of the virus, people that are suspected or confirmed to have the disease should be isolated from other patients and treated by health workers using strict infection control precautions.
What can I do? Can it be prevented? Is there a vaccine?
Currently, there is no licensed medicine or vaccine for Ebola virus disease, but several products are under development.
Can hospitals in the United States care for an Ebola patient?
Any U.S. hospital that is following CDC's infection control recommendations and can isolate a patient in their own roomâ with a private bathroom is capable of safely managing a patient with Ebola.
What does CDC's Travel Alert Level 3 mean to U.S. travelers?
CDC recommends that U.S. residents avoid nonessential travel to Guinea, Liberia, and Sierra Leone. If you must travel (for example, to do for humanitarian aid work in response to the outbreak) protect yourself by following CDC's advice for avoiding contact with the blood and body fluids of people who are ill with Ebola. For more information about the travel alerts, see Travelers' Health Ebola web page.
Travel notices are designed to inform travelers and clinicians about current health issues related to specific destinations. These issues may arise from disease outbreaks, special events or gatherings, natural disasters, or other conditions that may affect travelers' health. A level 3 alert means that there is a high risk to travelers and that CDC advises that travelers avoid nonessential travel.Travelers should avoid all contact with infected patients.
Is there a danger of Ebola spreading in the U.S.?
Ebola is not spread through casual contact; therefore, the risk of an outbreak in the U.S. is very low. We know how to stop Ebola's further spread: thorough case finding, isolation of ill people, contacting people exposed to the ill person, and further isolation of contacts if they develop symptoms. The U.S. public health and medical systems have had prior experience with sporadic cases of diseases such as Ebola. In the past decade, the United States had 5 imported cases of Viral Hemorrhagic Fever (VHF) diseases similar to Ebola (1 Marburg, 4 Lassa). None resulted in any transmission in the United States.
Are there any cases of people contracting Ebola in the U.S.?
CDC confirmed on September 30, 2014, the first travel-associated case of Ebola to be diagnosed in the United States. The person traveled from West Africa to Dallas, Texas, and later sought medical care at Texas Health Presbyterian Hospital of Dallas after developing symptoms consistent with Ebola. The medical facility isolated the patient, who died on October 8. Based on the person's travel history and symptoms, CDC recommended testing for Ebola.
On October 10, a healthcare worker at Texas Presbyterian Hospital who provided care for the index patient reported a low-grade fever and tested positive for Ebola. A second healthcare worker who also cared for the traveller from Liberia was diagonosed with Ebola on October 15, after having travelled from Dallas to Cleveland and back.
Are people who were on the plane with this patient at risk?
A person must have symptoms to spread Ebola to others. The healthcare worker did not have a fever and did not experience nausea or vomiting on the plane. As a precautionary measure since the return flight to Dallas was Monday night and the person reported symptoms the next morning, the CDC asked all 132 passengers on the plane to call a CDC hotline.
Why were the ill Americans with Ebola brought to the U.S. for treatment? How is CDC protecting the American public?
A U.S. citizen has the right to return to the United States. Although CDC can use several measures to prevent disease from being introduced in the United States, CDC must balance the public health risk to others with the rights of the individual. In this situation, the patients who came back to the United States for care were transported with appropriate infection control procedures in place to prevent the disease from being transmitted to others.
Ebola poses no substantial risk to the U.S. general population. CDC recognizes that Ebola causes a lot of public worry and concern, but CDC's mission is to protect the health of all Americans, including those who may become ill while overseas. Ebola patients can be transported and managed safely when appropriate precautions are used.
CDC is implementing enhanced entry screening at five U.S. airports that receive over 94% of travelers from Guinea, Liberia, and Sierra Leone.
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