Ebola

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Organism, Causative agent, Etiologic agent
The infectious agent of Ebola Virus Disease (EVD) is Ebolavirus, which is in the virus family Filoviridae. There are five identified Ebola virus species, four of which cause disease in humans: Zaire, Sudan, Taï Forest, and Bundibugyo.

Transmission
Ebola has been found in certain mammals (primates, bats) in Africa. It is thought that fruit bats of the Pteropodidae family are natural Ebola virus hosts. Ebola is introduced into the human population through close contact with the blood, secretions, organs or other bodily fluids of infected animals, such as chimpanzees, gorillas, fruit bats, monkeys, forest antelope and porcupines found ill or dead.

Once infection occurs in humans, there are several ways it can spread to others. Ebola is spread through direct contact (through broken skin, mucous membranes -eyes, nose, mouth, etc.) with:

• Blood or body fluids (including but not limited to urine, saliva, sweat, feces, vomit, breast milk, semen) of a person who is sick with or has died from Ebola
• Objects contaminated with the virus (e.g., surfaces, bedding, needles, syringes)
• Semen from a man who recovered from EVD through oral, vaginal or anal sex

Risk of transmission is highest during the late stages of the illness, when the infected person has very high levels of virus in their body and is vomiting, having diarrhea, or hemorrhaging. Risk of transmission is also high at the time of death, if unprotected contact with the body of the deceased occurs. Post-mortem transmission has been linked to the preparation of the body for burial and during burial rituals or funeral services.

The Ebola virus CANNOT spread to others when a person shows no signs or symptoms of EVD. It is not typically transmitted by food, except through handling or consumption of contaminated bush meat (wild animals hunted for food).

Symptoms
EVD is a severe acute illness, usually with sudden onset of fever, fatigue, malaise, muscle pain, severe headache, sore throat, vomiting, diarrhea, abdominal pain, rash, symptoms of impaired liver or kidney function, bruising and bleeding. Symptoms may appear anywhere from 2 to 21 days after contact with the virus, with an average of 8 to 10 days. Many common illnesses can have these same symptoms, including influenza (flu) or malaria. EVD is a rare but severe and often deadly disease. Recovery from EVD depends on good supportive clinical care and the patient’s immune response. Some survivors may have long-term complications, such as joint and vision problems. It is not known if people who recover are immune for life or if they can later become infected with a different species of Ebola virus.

Prevention
In the United States, EVD is a very rare disease. In other parts of the world, especially in sub-Saharan Africa, Ebola virus is more common (endemic).

When living in or traveling to a region where Ebola virus is more commonly found, there are a number of ways to protect yourself and prevent the spread of EVD. Practicing good hand hygiene is an effective method in preventing the spread of dangerous germs, like the Ebola virus. Proper hand hygiene means washing hands often with soap and water or an alcohol-based hand sanitizer.

While in an area affected by Ebola, it is important to avoid the following:

• Contact with blood and body fluids (such as urine, feces, saliva, sweat, vomit, breast milk, semen, and vaginal fluids).
• Items that may have come in contact with an infected person’s blood or body fluids (such as clothes, bedding, needles, and medical equipment).
• Funeral or burial rituals that require handling the body of someone who died from EVD.
• Contact with bats and nonhuman primates or blood, fluids and raw meat prepared from these animals (bushmeat) or meat from an unknown source.
• Contact with semen from a man who had EVD until you know the virus is gone from the semen.
  

These same prevention methods apply when living in or traveling to an area affected by an Ebola outbreak. After returning from an area affected by Ebola, monitor your health for 21 days and seek medical care immediately if you develop symptoms of EVD.

There is currently no vaccine licensed by the U.S. Food and Drug Administration (FDA) to protect people from Ebola virus. An experimental vaccine called rVSV-ZEBOV was found to be highly protective against the virus in a trial conducted by the World Health Organization (WHO) and other international partners in Guinea in 2015. FDA licensure for the vaccine is expected in 2018. In the meantime, 300,000 doses have been committed for an emergency use stockpile under the appropriate regulatory mechanism (Investigational New Drug application [IND] or Emergency Use Authorization [EUA]) in the event an outbreak occurs before FDA approval is received. Scientists continue to study the safety of this vaccine. This vaccine has been used during Ebola outbreaks in Africa. Research on other vaccines is also being conducted.

Texas Trends
In 2014, there were three cases of Ebola reported in Texas that were associated with the 2014-2016 West Africa Ebola Epidemic. The initial case was the first travel associated case of EVD diagnosed in the United States. Two nurses who cared for the sick Ebola patient (initial case) contracted EVD, marking the first known transmission of EVD in the United States. The patient died, both nurses recovered.