Anita Nwachuku, Pharm.D. Student, Nina Mezu-Nwaba, Pharm.D., MPH, MSc.
Ebola Virus Disease (EVD), formerly known as Ebola Hemorrhagic Fever (Ebola HF), is a severe infectious disease caused by the viral species Ebolavirus6,7. Four out of five of the identified subspecies of Ebolavirus can cause infection in humans. These include: Zaire ebolavirus, Sudan ebolavirus, Tai’ Forest ebolavirus, and Bundibugyo ebolavirus6,7.
The first outbreak of EVD was reported in 1976 in what is now known as the Democratic Republic of the Congo. This outbreak resulted in 280 deaths4. The current outbreak, which began earlier this year, has claimed the lives of over 1,000 people in West Africa. Most have been in Guinea, Liberia, and Sierra Leone3. Nigeria has confirmed 10 cases of the disease and four deaths.
Exposure to blood and other bodily fluids of ebola-infected animals such as fruit bats and monkeys is believed to have led to the introduction of Ebola into humans13. The disease can be transmitted from person to person through direct contact with blood or bodily fluids of an infected and symptomatic person9. The virus can also be transmitted through exposure to contaminated objects such as needles9. Once inside the body, the virus infects a number of cells including epithelial cells, dendritic cells, and macrophages7. If the virus reaches the lymphatic system the infection can spread to other parts of the body causing complications in multiple organ systems7.
Early presentation of EVD can be confused with other tropical diseases such as malaria and typhoid fever7. Common signs and symptoms include6,7:
These symptoms usually occur 8-10 days after exposure but may appear between 2-21 days after7. Complications of the infection include hypoxia, hypovolemia, hemorrhage, septic shock, and multi-organ failure,7.
A number of laboratory tests are used to diagnose EVD. These include5:
The US Food and Drug Administration (FDA) recently issued an Emergency Use Authorization to allow the use of the US Department of Defense (DoD) Ebola Zaire (Target 1) Real-Time PCR (TaqMan®) or EZ1 rRT-PCR Test to detect the presence of Zaire ebolavirus11,12.
There is NO approved treatment for EVD. The current standard of care is supportive with focus on the management of symptoms. This includes6,7:
A number of pharmaceutical companies are working to develop treatment options for EVD. ZMapp is an investigational drug that is being developed by Mapp Biopharmaceuticals Inc9. The drug contains a combination of monoclonal antibodies and has NOT been tested for safety or effectiveness in humans9. Biocryst Pharmaceuticals is working with the US National Institute of Health (NIH) to develop an antiviral drug treatment for EVD that is scheduled to enter phase 1 clinical trials9. Lastly, Tekmira Pharmaceuticals has developed an Ebola candidate, called TKM-Ebola, which will soon enter phase 1 trial2,9.
Prevention methods are crucial to decreasing the rate of transmission of Ebola. These methods include8,13:
There are NO approved vaccines for EVD9. However, research efforts are being intensified to develop vaccine candidates. The US NIH's National Institute of Allergy and Infectious Diseases is planning to begin phase 1 trials for a vaccine this year9. Crucell, Profectus Biosciences, and the US Department of Defense are working to expedite the approval of vaccine candidates for EVD9.
National and International Responses
In addition to issuing the Emergency Use Authorization for the DoD’s diagnostic test, the FDA is continuing to work with the industry to provide options for infected patients. The organization recently modified a hold on the novel drug, TKM-Ebola, to allow for use in infected patients2.
The US Centers for Disease Control and Prevention
The CDC has taken a number of steps to respond to the outbreak. The organization has activated its Emergency Operations Center and is working with hospitals in the United States to prepare them for the management of potential suspected cases10. Additionally, the CDC is helping to identify individuals who are showing signs and symptoms of the disease and has provided public health workers to help countries in their efforts to contain the outbreak10.
The WHO is taking a leading role in responding to the current Ebola outbreak. In July, the organization provided personal protective equipment to health workers in Liberia1. Recently, WHO approved the use of experimental drugs, following a panel discussion on the ethical implications of using therapies that haven’t been tested in humans.
While there is no cure or vaccine for EVD, there are several initiatives to not only control the spread of the disease but also provide options for individuals who have the infection. It is important that anyone traveling to countries with confirmed cases of Ebola outbreak take the necessary precautions to prevent further spread of the virus.
1. Banluta, C. (2014). WHO supplies personal protective equipment to health workers responding to Ebola. Retrieved from: http://www.who.int/features/2014/ebola-liberia/en/
2. Nickel, R. (2014, August 1). Tekmira Ebola drug gets regulator change for possible human use. Reuters. Retrieved from: http://www.reuters.com/article/2014/08/07/us-health-ebola-tekmira-idUSKBN0G72FQ20140807
3. The Centers for Disease Control and Prevention (2014). 2014 Ebola Outbreak in West Africa. Retrieved from: http://www.cdc.gov/vhf/ebola/outbreaks/guinea/index.html
4. The Centers for Disease Control and Prevention. (2014). Chronology of Ebola Hemorrhagic Fever Outbreaks. Retrieved from:http://www.cdc.gov/vhf/ebola/resources/outbreak-table.html
5. The Centers for Disease Control and Prevention (2014). Diagnosis. Retrieved from http://www.cdc.gov/vhf/ebola/diagnosis/index.html
6. The Centers for Disease Control and Prevention. (2014). Ebola Fact Sheet. Retrieved from: http://www.cdc.gov/vhf/ebola/resources/pdfs/Ebola-FactSheet.pdf
7. The Centers for Disease Control and Prevention (2014). Ebola Virus Disease Information for Clinicians in U.S. Healthcare Settings. Retrieved from http://www.cdc.gov/vhf/ebola/hcp/clinician-information-us-healthcare-settings.html
8. The Centers for Disease Control and Prevention (2014). Infection Prevention and Control Recommendations for Hospitalized Patients with Known or Suspected Ebola Hemorrhagic Fever in U.S. Hospitals. Retrieved from http://www.cdc.gov/vhf/ebola/hcp/infection-prevention-and-control-recommendations.html
9. The Centers for Disease Control and Prevention (2014). Questions and Answers on experimental treatments and vaccines for Ebola. Retrieved from http://www.cdc.gov/vhf/ebola/outbreaks/guinea/qa-experimental-treatments.html
10. The Centers for Disease Control and Prevention (2014). What CDC is Doing. Retrieved from:http://www.cdc.gov/vhf/ebola/what-cdc-doing.html
11. The Food and Drug Administration. (2014). Fact Sheet for Health Care Providers: Interpreting Ebola Zaire (Target 1) Real-Time PCR (TaqMan®) (EZ1 rRT-PCR) Assay Results. Retrieved from:http://www.fda.gov/downloads/medicaldevices/safety/emergencysituations/ucm408332.pdf
12. The Food and Drug Administration. (2014). Fact Sheet for Patients: Understanding Results from the Ebola Zaire (Target 1) Real-Time PCR (TaqMan®) (EZ1 rRT-PCR) Test. Retrieved from:http://www.fda.gov/downloads/medicaldevices/safety/emergencysituations/ucm408333.pdf
13. World Health Organization (2014) Ebola Virus Disease. Retrieved from: http://www.who.int/mediacentre/factsheets/fs103/en/