By: Azia Tariq, Staff Editor
The first recorded outbreak of the Ebola Zaire (ZEBOV), a strain of the ebola virus, occurred in 1976. Since then, three additional types of the deadly virus have been discovered: Sudan Ebola virus (SEBOV), Reston Ebola virus (REBOV), and Côte d’Ivoire Ebola virus (CIEBOV).1 The initial outbreak had, until recently, the highest number of recorded deaths, taking approximately 280 lives. With 779 reported cases and 481 fatalities, the sheer number of cases in the 2014 outbreak signifies how deadly the current outbreak in West Africa can be.2 It is the largest outbreak in terms of deaths, number of cases, and geographical spread. The disease has been steadily spreading from Guinea to parts of Liberia and Sierra Leone and the number of cases will continue to increase until the virus has been contained.
Genetic analysis of the virus indicates that it is 97% identical to variants of the Zaire species.3 Researchers identified the strain in a brief report in the New England Journal of Medicine. To detect the causative agent, Filoviridae-specific Real-time Polymerase Chain reaction (RT-PCR) assays that target a conserved region in the L gene were utilized. In addition, the exact strain was confirmed using EBOV-specific real-time RT-PCR assays targeting the glycoprotein (GP) or nucleoprotein (NP) gene. Samples from 15 of the 20 patients tested positive in the conventional L gene PCR assay and the real-time assays, indicating that the virus was indeed Ebola.4
As with the other strains of the Ebola virus, the symptoms are at first nonspecific or may resemble numerous disorders, leading those affected to assume that he or she has an innocuous illness. The incubation period is anywhere from 2 to 21 days. Days after the initial infection, the condition progressively worsens and results in nausea, vomiting, diarrhea, fever, and hemorrhages.5 The case fatality rate was found to be 86% among the early confirmed cases and 71% among clinically suspected cases, which is consistent with the case fatality rates observed in previous EBOV outbreaks.4
The stigma associated with the disease has made it more difficult to trace and contain as many deny being in contact with infected persons when questioned by health workers. As a result, rather than seeking medical attention, infected individuals resort to leaving their homes and traveling to other locations in order to escape the negative perceptions. Thomas Fletcher, M.D, from the Department of Pandemic and Epidemic Diseases at the World Health Organization, who is currently managing Ebola virus infection cases in Conakry, Guinea, explained what his patients experience and what can be done to improve care. “I’ve never encountered such a frightened group of patients,” he said. “Bear in mind they have often seen their family members die, and they can almost chart their progression through the symptoms, especially the healthcare workers who obviously have an increased knowledge.”5 He stresses that combating patient fear is crucial for healthcare delivery and infection control cooperation in the community. Fear can lead to reluctance within the community to identify and isolate possibly infected individuals, which hinders treatment.
Heinz Feldmann, MD, PhD, who studies Ebola and other hemorrhagic fever viruses at the National Institute of Allergy and Infectious Diseases, confirms that there is still a long way to go before a vaccine or treatment is developed for any Ebola virus. Countermeasures against the disease mainly consist of identification and support. A few treatment approaches have shown some promise, though they have yet to reach Phase I of human clinical trials. Therapeutic interventions that demonstrate some potential include antibody treatment and small interfering RNAs or phosphorodiamidate morpholino oligomers. The former treatment has been successful in macaques, any monkey of the genus Macaca, even when antibodies are administered more than 72 hours after infection. Treatment via a small synthetic molecule, BCX4430.5, also seems plausible. The most likely vaccine approaches are based on recombinant technologies, such as virus-like particles produced through plasmid transfection as well as replication-incompetent and replication-competent viral vectors.6
As treatment options are limited, it is vital to remain diligent in identifying and isolating the virus and those infected so that the situation is not further exacerbated. It is equally important to ensure that the community is educated about the misconceptions of the disease and that patients know when to seek care.
- Outbreak Table- Ebola Hemorrhagic Fever. CDC. Available at: http://www.cdc.gov/vhf/ebola/resources/outbreak-table.html. Accessed August 2, 2014.
- Ebola virus disease, West Africa – update. WHO. Available at: http://www.who.int/csr/don/2014_07_03_ebola/en/. Accessed August 2, 2014.
- Outbreak of Ebola in Guinea and Liberia. RxList. Available at: http://www.rxlist.com/script/main/art.asp?articlekey=177838. Accessed August 2, 2014.
- Baize S, Pannetier D, Oestereich L, et al. Emergence of Zaire Ebola virus disease in Guinea – Preliminary Report. New England Journal of Medicine. Available at: http://www.nejm.org/doi/suppl/10.1056/NEJMoa1404505/suppl_file/nejmoa1404505_prelim.pdf Accessed August 2, 2014.
- First-Hand Experience From Guinea Offers New Ebola Insight. Medscape. Available at: http://www.medscape.com/viewarticle/825220#2. Accessed August 2, 2014.
- Feldmann H. Ebola – A Growing Threat? New England Journal of Medicine. Available at: http://www.nejm.org/doi/full/10.1056/NEJMp1405314.
[pubmed_related keyword1=”ebola” keyword2=”virus” keyword3=”africa”]