There are five identified subspecies of Ebolavirus. Four of the five have caused disease in humans: Ebola virus (Zaire ebolavirus); Sudan virus (Sudan ebolavirus); Taï Forest virus (Taï Forest ebolavirus, formerly Côte d’Ivoire ebolavirus); and Bundibugyo virus (Bundibugyo ebolavirus). The fifth, Reston virus (Reston ebolavirus), has caused disease in nonhuman primates, but not in humans.
The natural reservoir host of ebolaviruses remains unknown. However, on the basis of available evidence and the nature of similar viruses, researchers believe that the virus is zoonotic (animal-borne) with bats being the most likely reservoir. Four of the five subtypes occur in an animal host native to Africa.
In the initial RESPONSE TO OUTBREAKS, a team of investigators from the CDC Special Pathogens Branch traveled to Uganda. They worked to bring the outbreak under control and learn more about the reservoir hosts for the Ebola and Marburg viruses.Please watch this 6 minute video for valuable information on the Ebola virus and how the CDC responds in an Ebola crises situation.
Please note that a host of similar species is probably associated with Reston virus, which was isolated from infected cynomolgous monkeys imported to the United States and Italy from the Philippines. Several workers in the Philippines and in US holding facility outbreaks became infected with the virus, but did not become ill.
Related Links: Questions and Answers on Ebola:
Source: CDC
B. Ebola Epidemic Fact Sheet
1. Ebola
Ebola hemorrhagic fever (Ebola HF) is one of numerous Viral Hemorrhagic Fevers. Ebola HF is caused by infection with a virus of the family Filoviridae, genus Ebolavirus. When infection occurs, symptoms usually begin abruptly. The first Ebolavirus species was discovered in 1976 in what is now the Democratic Republic of the Congo near the Ebola River. Since then, outbreaks have appeared sporadically.
There are five identified subspecies of Ebolavirus. Four of the five have caused disease in humans: Ebola virus (Zaire ebolavirus); Sudan virus (Sudan ebolavirus); Taï Forest virus (Taï Forest ebolavirus, formerly Côte d’Ivoire ebolavirus); and Bundibugyo virus (Bundibugyo ebolavirus). The fifth, Reston virus (Reston ebolavirus), has caused disease in nonhuman primates, but not in humans. The natural reservoir host of ebolaviruses remains unknown. However, on the basis of available evidence and the nature of similar viruses, researchers believe that the virus is zoonotic (animal-borne) with bats being the most likely reservoir. Four of the five subtypes occur in an animal host native to Africa.
A host of similar species is probably associated with Reston virus, which was isolated from infected cynomolgous monkeys imported to the United States and Italy from the Philippines. Several workers in the Philippines and in US holding facility outbreaks became infected with the virus, but did not become ill.
2. Transmission
Because the natural reservoir of ebolaviruses has not yet been proven, the manner in which the virus first appears in a human at the start of an outbreak is unknown. However, researchers have hypothesized that the first patient becomes infected through contact with an infected animal.
When an infection does occur in humans, there are several ways in which the virus can be transmitted to others. These include:
• direct contact with the blood or secretions of an infected person
• exposure to objects (such as needles) that have been contaminated with infected secretions
The viruses that cause Ebola HF are often spread through families and friends because they come in close contact with infectious secretions when caring for ill persons. During outbreaks of Ebola HF, the disease can spread quickly within health care settings (such as a clinic or hospital). Exposure to ebolaviruses can occur in health care settings where hospital staff are not wearing appropriate protective
equipment, such as masks, gowns, and gloves. Proper cleaning and disposal of instruments, such as needles and syringes, is also important. If instruments are not disposable, they must be sterilized before being used again. Without adequate sterilization of the instruments, virus
transmission can continue and amplify an outbreak.
3. Signs and Symptoms
Symptoms of Ebola HF typically include: Some patients may experience:
• Fever
• Headache
• Joint and muscle aches
• Weakness
• Diarrhea
• Vomiting
• Stomach pain
• Lack of appetite
• A Rash
• Red Eyes
• Hiccups
• Cough
• Sore throat
• Chest pain
• Difficulty breathing
• Difficulty swallowing
• Bleeding inside and outside of the body
Symptoms may appear anywhere from 2 to 21 days after exposure to ebolavirus though 8-10 days is most common. Some who become sick with Ebola HF are able to recover, while others do not. The reasons behind this are not yet fully understood. However, it is known that patients who die usually have not developed a significant immune response to the virus at the time of death.
4. Risk of Exposure
In Africa, confirmed cases of Ebola HF have been reported in:
• Democratic Republic of the Congo (DRC)
• Gabon
• South Sudan
• Ivory Coast
• Uganda
• Republic of the Congo (ROC)
• South Africa (imported)
The natural reservoir host of ebolaviruses, and the manner in which transmission of the virus to humans occurs, remain unknown. This makes risk assessment in endemic areas difficult. Currently, all cases of illness or death have occurred in Africa; no case has been reported in the United States.
During outbreaks of Ebola HF, those at highest risk include health care workers and the family and friends of an infected individual. Health care workers in Africa should consult the Infection Control for Viral Hemorrhagic Fevers In the African Health Care Setting to learn how to prevent and control infections in these setting. Medical professionals in the United States should consult the Interim Guidance for Managing Patients with Suspected Viral Hemorrhagic Fever in U.S. Hospitals.
5. Diagnosis
Diagnosing Ebola HF in an individual who has been infected for only a few days is difficult, because the early symptoms, such as red eyes and a skin rash, are nonspecific to ebolavirus infection and are seen often in patients with more commonly occurring diseases. However, if a person has the early symptoms of Ebola HF and there is reason to believe that Ebola HF should be considered, the patient should be isolated and public health professionals notified. Samples from the patient can then be collected and tested to confirm infection.
Laboratory tests used in diagnosis include:
– Antigen-capture enzyme-linked immunosorbent assay (ELISA) testing
– IgM ELISA
– Polymerase chain reaction (PCR)
– Virus isolation
– PCR
– Virus isolation (Please note that if there is reason to believe that Ebola HF should be considered, the patient should be isolated and public health professionals notified. Supportive therapy can continue with proper protective clothing until samples from the patient are tested to confirm infection).
6. Treatment
Standard treatment for Ebola HF is still limited to supportive therapy. This consists of:
• balancing the patient’s fluids and electrolytes
• maintaining their oxygen status and blood pressure
• treating them for any complicating infections
Timely treatment of Ebola HF is important but challenging since the disease is difficult to diagnose clinically in the early stages of infection. However, if a person has the early symptoms of Ebola HF and there is reason to believe that Ebola HF should be considered, the patient should be isolated and public health professionals notified. Supportive therapy can continue with proper protective clothing until samples from the patient are tested to confirm infection. Experimental treatment has been tested and proven effective in animal models but has not yet been used in humans.
7. Prevention
The prevention of Ebola HF presents many challenges. Because it is still unknown how exactly people are infected with Ebola HF, there are few established primary prevention measures. When cases of the disease do appear, there is increased risk of transmission within health care settings. Therefore, health care workers must be able to recognize a case of Ebola HF and be ready to employ practical viral hemorrhagic fever
isolation precautions or barrier nursing techniques. They should also have the capability to request diagnostic tests or prepare samples for shipping and testing elsewhere.
Barrier nursing techniques include:
• wearing of protective clothing (such as masks (N95 respirators recommended), nitrile gloves, gowns, and disposable face shields)
• the use of infection-control measures (such as complete equipment sterilization and routine use of disinfectant)
• isolation of Ebola HF patients from contact with unprotected persons
The aim of all of these techniques is to avoid contact with the blood or secretions of an infected patient. If a patient with Ebola HF dies, it is equally important that direct contact with the body of the deceased patient be prevented. CDC, in conjunction with the World Health Organization, has developed a set of guidelines to help prevent and control the spread of Ebola HF. Entitled Infection Control for Viral Hemorrhagic Fevers In the African Health Care Setting, the manual describes how to:
• recognize cases of viral hemorrhagic fever (such as Ebola HF)
• prevent further transmission in health care setting by using locally available materials and minimal financial resources
Source CDC : http://www.cdc.gov/vhf/ebola/resources/pdfs/ebola-factsheet.pdf
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8. Ebola Vaccine Research
The Vaccine Research Center (VRC) has developed an Ebola vaccine candidate in collaboration with Okairos, a Swiss-Italian biotech company recently acquired by GSK. The investigational vaccine, which was designed by VRC scientists, contains no infectious Ebola virus material. It is a chimpanzee adenovirus vector vaccine into which two Ebola genes have been inserted. This is a non-replicating viral vector, which means the vaccine enters a cell, delivers the gene inserts and does not replicate further. The gene inserts express a protein to which the body makes an immune response. The investigational vaccine has recently shown promise in a primate model. The VRC vaccine will enter into a phase 1 clinical trial, which could start enrollment as early as fall 2014, pending approval by the FDA. The VRC is also in discussions with governmental and non-governmental partners regarding options for advancing this candidate beyond Phase I clinical evaluation.
Additionally, NIAID’s Division of Microbiology and Infectious Diseases is supporting the Crucell biopharmaceutical company’s development of a multivalent Ebola/Marburg vaccine using recombinant adenovirus vector platforms. A Phase I clinical trial is planned for late 2015 or early 2016. NIAID is also funding Profectus Biosciences to develop and test a recombinant vesicular stomatitis virus vectored vaccine against Ebolavirus. The vaccine is currently in preclinical testing to determine the most promising constructs. In addition, NIAID is working with Bavarian Nordic on development of a recombinant Marburg vaccine candidate that uses the Modified Vaccinia Ankara vector.
Investigators from NIAID’s Division of Intramural Research and Thomas Jefferson University are collaborating to develop a candidate Ebola vaccine based on the established rabies virus vaccine that has demonstrated protection against rabies and Ebola infection in animals. This research team is pursuing an inactivated version of this vaccine for human and veterinary use and a live vaccine for use in wildlife in Africa to help prevent the transmission of Ebolavirus from animals to humans.
Source: http://www.niaid.nih.gov/topics/ebolamarburg/research/pages/default.aspx
9. Information for Clinicians in U.S. Healthcare Settings
Patients with EVD generally have abrupt onset of typically 8-10 days after exposure (mean 4-10 days in previous outbreaks, range 2-21 days). Initial signs and symptoms are nonspecific and may include fever, chills, myalgias, and malaise. Fever, anorexia, asthenia/weakness are the most common signs and symptoms. Patients may develop a diffuse erythematous maculopapular rash by day 5 to 7 (usually involving the face, neck, trunk, and arms) that can desquamate.
Due to these nonspecific symptoms particularly early in the course, EVD can often be confused with other more common infectious diseases such as malaria, typhoid fever, meningococcemia, and other bacterial infections (e.g., pneumonia).
Patients can progress from the initial non-specific symptoms after about 5 days to develop gastrointestinal symptoms such as severe watery diarrhea, nausea, vomiting and abdominal pain. Other symptoms such as chest pain, shortness of breath, headache or confusion, may also develop. Patients often have conjunctival injection. Hiccups have been reported. Seizures may occur, and cerebral edema has been reported. Bleeding is not universally present but can manifest later in the course as petechiae, ecchymosis/bruising, or oozing from venipuncture sites and mucosal hemorrhage. Frank hemorrhage is less common. Pregnant women may experience spontaneous miscarriages.
Patients with fatal disease usually develop more severe clinical signs early during infection and die typically between days 6 and 16 of complications including multi-organ failure and septic shock. In non-fatal cases, patients may have fever for several days and improve, typically around day 6-11. Patients that survive can have a prolonged convalescence. The World Health Organization has estimated the mortality of the current outbreak of EVD in West Africa to be approximately 55%, but appears to be as high as 75% in Guinea.
Pathogenesis
Ebola virus enters the patient through mucous membranes, breaks in the skin, or parenterally and infects many cell types, including monocytes, macrophages, dendritic cells, endothelial cells, fibroblasts, hepatocytes, adrenal cortical cells and epithelial cells. The incubation period may be related to the infection route (i.e., 6 days for injection versus 10 days for contact). Ebola virus migrates from the initial infection site to regional lymph nodes and subsequently to the liver, spleen and adrenal gland. Although not infected by Ebola virus, lymphocytes undergo apoptosis resulting in decreased lymphocyte counts. Hepatocellular necrosis occurs and is associated with dysregulation of clotting factors and subsequent coagulopathy. Adrenocortical necrosis also can be found and is associated with hypotension and impaired steroid synthesis. Ebola virus appears to trigger a release of pro-inflammatory cytokines with subsequent vascular leak and impairment of clotting ultimately resulting in multi-organ failure and shock.
http://www.cdc.gov/vhf/ebola/hcp/clinician-information-us-healthcare-settings.html
Five Strains
Ebola is caused by infection with a virus of the family Filoviridae, genus Ebolavirus. There are five identified Ebola virus species, four of which are known to cause disease in humans: Ebola virus (Zaire ebolavirus); Sudan virus (Sudan ebolavirus); Taï Forest virus (Taï Forest ebolavirus, formerly Côte d’Ivoire ebolavirus); and Bundibugyo virus (Bundibugyo ebolavirus). The fifth, Reston virus (Reston ebolavirus), has caused disease in nonhuman primates, but not in humans. Source: http://www.cdc.gov/vhf/ebola/about.html
In Summary:
*Please note that this flyer has gone through several revisions from the CDC (Center of Disease Control). Visit the CDC website, as listed in the appendix of this course, for the most updated versions if applicable.
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Required Reading:
C. Ebola Outbreaks 2000-2014. Review the 14 Outbreaks
D. August 29, 2014 NIH Release on Ebola Review it
E. CDC Update………………………………………………Review it.
“It is the world’s first Ebola epidemic and it is spiraling out of control. It’s bad now and it’s going to get worse in the very near future,” Frieden of the CDC told reporters. “There is still a window of opportunity to tamp it down, but that window is closing. We really have to act now.”
F. Sept 6, 2014, NYT Update….. …..Review all NYT articles on Ebola.
G. Transmission Guidelines Mapping the outbreak The virus and the disease
http://www.phe.gov/about/OPP/dhsp/Documents/ebola-openletterhealthcareprofessionals.pdf
TEST
TEST 7116 for 3 CE hours course accredited by the California Board of Registered Nursing, PCE 16144: Click here to take the 10-item test online and make payment, and to print your certificate.
Discussion Questions
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Recommendations for you: Visit our “Emergency Preparedness” class at (https://cecourses.org/more/emergency-preparedness/), to learn how to identify basic strategies for surviving a disaster in both a healthcare and non-healthcare setting, specific hazards that can affect all individuals globally, and increase overall awareness for EBOLA.
Reading Recommendations: “Plan B: Rescued from Destruction” by Rudolf Klimes http://www.amazon.com/Plan-
