Ebola is a viral hemorrhagic (bleeding) illness that has a high fatality rate. The virus was discovered in 1976 near the Ebola River in the present day Democratic Republic of Congo. There are five strains of the Ebola virus -- Tai Forest, Sudan, Bundibugyo, Zaire, and Reston. Four of the strains (Reston is the exception) are responsible for outbreaks in humans. The Ebola virus is harbored by fruit bats, gorillas, monkeys, forest antelope, chimpanzees, and porcupines. Humans can contract the virus by coming into close contact with the body or bodily fluids (including blood) of an infected animal. Once the virus spreads to a human, person-to-person transmission is possible.
Since 1976, outbreaks have occurred sporadically in Zaire, Sudan, Democratic Republic of Congo, Gabon, and Uganda. The largest outbreak, beginning in March 2014, affects Guinea, Liberia, Sierra Leone, Senegal, and Nigeria. The West Africa Ebola outbreak is the largest in history with 28,652 reported cases and 11,325 deaths as of April 2016. Visit the Centers for Disease Control (CDC) website for the latest outbreak statistics.
In between human outbreaks, Ebola is believed to be harbored in animals that act as a “reservoir” for the virus. When a human contracts Ebola by handling an infected animal, person-to-person transmission can then lead to an outbreak. Ebola can be transmitted directly or indirectly. Direct transmission refers to the virus passing from the blood or other bodily fluids of an infected person to another person via sexual contact or by infected body fluids (tears, feces, urine, vomit, for example) that contact the mucous membranes, or broken skin. Indirect transmission refers to a person picking up a virus from a contaminated object, such as infected surgical equipment or a needle.
The signs and symptoms of Ebola virus include fever greater than 101°F, vomiting, diarrhea, sore throat, severe headache, joint/muscle pain, abdominal pain, weakness, rash, and internal bleeding. Some people with the illness may bleed from the eyes, nose, ears, and rectum. Lab tests may reveal abnormal liver and kidney function. Levels of white blood cells and platelets may be elevated. The incubation period of Ebola, defined as the period of time from exposure to the virus until the onset of symptoms, is 21 days. The average time from exposure to symptom development is about 8 – 10 days; bleeding is usually a later symptom that signifies severe infection.
In lab conditions, the Ebola virus has been shown to spread through the air. However, in real-world living conditions and in hospital settings, there is no evidence that Ebola can be transmitted through the air. While there are fears that Ebola could mutate and become more easily transmissible, the director of the CDC, Dr. Tom Frieden, stated that there has been little change in the Ebola virus in the past 40 years. He also said that there is no evidence that Ebola has undergone any changes that would make it easier to spread from person to person.
Every Ebola outbreak is different. Historically, the larger Ebola outbreaks have had a fatality rate of 50% to almost 90%. The reported fatality rate for suspected cases of the West Africa Ebola outbreak that began in March 2014 is about 40% as of April 2016.
There is no cure for Ebola. New therapies are being investigated. Treatment for Ebola consists of supportive care which often includes administering intravenous (IV) fluids and monitoring and maintaining appropriate electrolyte, oxygen, and blood pressure levels. Prevention and treatment of other infections that may develop in the Ebola-infected patient is important as well.
There currently is no FDA-approved vaccine for the Ebola virus. The National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health (NIH), is working to develop an Ebola vaccine. In light of the West Africa Ebola outbreak, scientists from the NIAID, other international health agencies, and pharmaceutical companies, are expediting the research of several potential Ebola vaccines.
An experimental therapy for Ebola is being developed called ZMapp. The therapy consists of three monoclonal antibodies that are designed to treat existing Ebola infection. Monoclonal antibodies work by binding to proteins in the virus and “targeting” them for destruction by the immune system. More research is needed to assess the safety and efficacy of ZMapp before it can be considered for FDA approval and Ebola treatment.
Other potential therapy for Ebola infections are antiviral medications that interfere or stop Ebola virus replication. More studies are needed to determine the potential effectiveness of such experimental drugs.
People in areas known to have cases of Ebola can take the following precautions to minimize the risk of contracting the virus. Meticulous hygiene is necessary. Avoid people and bodily fluids of those known or suspected of having Ebola. Do not have contact with bats and wild animals; do not consume raw or undercooked animals that may have the virus. Only highly specialized, trained professionals with adequate protective gear should administer medical care to Ebola patients and handle the dead bodies of Ebola victims. Should you need medical care while you are in an area known to harbor Ebola, contact your embassy or consulate for a referral for an appropriate facility.
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