I. Overview The Ebola virus continues to spread in western Africa, and two infected U.S. doctors have arrived at Emory University Hospital in Atlanta for treatment. It is now of utmost importance that all medical personnel are aware of this progressively worsening outbreak.
Past Ebola outbreaks in western Africa have been regional and well-controlled. This year’s outbreak, which began in March, is much more extensive and unprecedented in its severity. Last week, a traveler took a flight from Liberia to Lagos (Nigeria) on which he already showed symptoms of the virus and died five days after landing. This has led to concerns that the outbreak may spread further.
The U.S. Centers for Disease Control and Prevention (CDC) has a Level 3 travel alert for the area in question, meaning that all non-essential travel should be prohibited. Efforts to contain the spread of the virus are not currently yielding effective results, which requires the international community, including the World Health Organization and the CDC, to work with the United Nations.
A U.S. CDC official said more health care professionals are needed in rural areas and modern equipment to control the virus is essential.
Second, the knowledge of Ebola virus Ebola virus infection, the patient’s morbidity and mortality rate of up to 90 percent. The current outbreak is concentrated in Guinea, Sierra Leone, and Liberia. It has caused more than 1,353 confirmed infections and 729 deaths, with a current mortality rate equivalent to approximately 53%.
The Ebola virus belongs to the filovirus family and was first isolated in 1976. There are currently five recognized subtypes of Ebola virus, four of which can be pathogenic to humans. The Reston subtype (Reston) infects only primates. The most lethal is the Zaire subtype, whose natural host is the fruit bat. The virus has also been isolated in porcupines, primates, and wild antelopes.
The incubation period for Ebola infection in humans is 2-21 days, with most patients becoming critically ill after 8-9 days of infection. Once infected, patients develop symptoms within 1-2 days.
Symptoms of Ebola virus infection include.
1. sudden onset of fever, often as high as 103?-105?F (39,4-40,5°C); 2. extreme weakness, sore throat, and headache; 3. profuse vomiting and diarrhea (1-2 days after the onset of the above symptoms).
More severe symptoms, such as coagulation disorders with thrombocytopenia, can occur within 24-48 hours. This leads to bleeding in the nasal or oral cavity, accompanied by bleeding blisters on the skin. Within 3-5 days, renal failure develops and leads to multi-organ failure and diffuse intravascular coagulation, accompanied by significant fluid loss.
Patients usually die within 8-9 days after the onset of the disease. Patients who survive for more than 2 weeks have a better prognosis for survival.
Third, Ebola is more difficult to diagnose The difficulty in diagnosing Ebola lies in the early stages of viral infection, when the symptoms are similar to those of other types of infectious diseases, such as malaria, Lassa fever, typhoid, cholera, and even meningitis. Only after 3-5 days (or later), with internal bleeding, does the characteristic feature of the disease – hemorrhagic blisters – become apparent.
Ebola cannot be transmitted by droplets and is not as contagious as measles or influenza. In contrast to patients with measles or influenza, who can transmit the virus before the onset of symptoms, Ebola is contagious only after the onset of symptoms in those infected with Ebola.
In addition, direct contact with the secretions of an infected person, such as saliva, is the basic route of Ebola transmission. However, Ebola cannot be transmitted by coughing or sneezing, nor is it transmitted by casual contact.
Instead, it is transmitted by direct contact with the patient’s secretions such as vomit, diarrhea or blood. It can also be transmitted through direct contact with the patient’s saliva, sweat, and tears.
Other routes of transmission include contact with the patient’s skin wounds or healing wounds, or contact with the patient’s secretions, or touching the patient’s eyes, nose, or mouth.
It is important to note that only those patients who are symptomatic are contagious. Those infected by the virus are primarily health care workers who are responsible for caring for the patient and family members who have close contact with the patient. Another way to get infected are those family members who handle the carcasses, and those who eat fruit bats, antelopes, or other animals that may be infected with the virus.
Studies have shown that the virus is present in higher concentrations in blood and vomit and diarrhea than in saliva, sweat, and tears. Disinfecting public places such as restrooms can curb the spread of the virus.
The actual risk of contracting the virus for citizens living and working in the United States is quite low. The public should be aware that U.S. emergency departments (EDs) and critical care units are well equipped to receive patients returning from travel to West Africa with flu and gastrointestinal symptoms.
EDs are often the proverbial “front door” to hospitals. Universal precautions, as well as quarantine and isolation of patients, are now a priority in every emergency department. This program requires health care workers to wear personal protective equipment, including glasses or goggles, masks, gloves and gowns.
Effective disinfection methods for the virus, including steam sterilization, chemical disinfection, and incineration.
Fourth, treatment for Ebola is limited Although human vaccine trials may be promising, the only treatment available for Ebola now is symptomatic supportive therapy (intravenous fluids, blood and platelet transfusions).
According to Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases (NIAID), the National Institutes of Health will begin human trials of a vaccine in September 2014. A human trial of the vaccine was tried earlier in the century, but was not successful.
The current vaccine was developed by the NIAID Vaccine Research Center and it does not contain infectious Ebola virus. It is actually a chimpanzee adenovirus vector vaccine that incorporates 2 Ebola virus genes.
Adenoviral vectors are commonly used to carry the target gene due to the ease of manipulation of this virus. As a non-replicating viral vector, the vaccine delivers new genetic material to the cell. The new gene is expressed to form a protein, which generates an immune response in the body. According to the NIAID, the vaccine has shown promising results in primate models.
Another approach involves transfusion of plasma from recovering healthy Ebola-infected patients. This approach assumes that the plasma of recovered patients contains life-saving neutralizing antibodies. According to the latest reports during this outbreak, this experimental treatment is already in clinical use, although the efficacy of the therapy is unknown.
There is also an experimental compound that was previously published in the April 2014 issue of Nature and is known as BCX4430 that holds some promise. This compound is an RNA-dependent inhibitor of RNA polymerase. Its application in a nonhuman primate model was successful, with 18 macaques using BCX4430 after Ebola exposure and only one death. The compound has not yet been reported for human trials.