Dianne Bettick
CNA

Disease

Ebola Hemorrhagic Fever

Causative Agents

The Ebola virus of the Filoviridae family causes severe hemorrhagic fever.  This virus has one, single stranded, negative RNA and has an enveloped pleomorphism (def) shape.  This means it can morph into several different shapes and can measure 80 nm in diameter and can be up to 14,000 nm long.   The primary source of Ebola is unknown and scientists are continually trying to uncover it before another outbreak occurs.

Epidemiology

The only known case of Ebola infection in the United States is a strain known as Ebola Reston.  Although this particular strain was fatal for the research monkeys that brought it with them, it was not for the humans exposed to it.  There are however many cases in the Sub-Saharan Africa region that are extremely lethal to humans.  In fact, one of the four strains of Ebola, each of which is named after the region it has afflicted, EBO-Z has a mortality rate of 89%.  Outbreaks of Ebola Hemorrhagic Fever have been very sporadic throughout the past 34 years when Ebola was first detected.  Anywhere between 1 and several hundred cases were reported in various years in the most prevalent areas of infection.  
    
The mortality rate varied as well for these reported cases.   The highest mortality, as stated before, occurred from the Ebola Virus Zaire which had an average 81.3% mortality rate.  Ebola Virus Sudan had an average mortality rate of 54.5% and Ebola Virus Côte-d’Ivoire did not seem to have any deaths reported as did Ebola Reston.  Although the racial group most affected was black this could merely be because the regions most infected have high populations of this racial group.  There does not seem to be any significance between sex and age group, however children do seem to be less afflicted.  This could be due to no other reason than their lack of exposure to other infected adults.

Transmission

The vector for human acquired Ebola Hemorrhagic Fever is most likely primates.  It can be spread through blood, secretions, or contaminated objects.  Contamination through the air has only been seen in laboratory settings and from monkey to monkey with regard to the Ebola Reston cases. 

Signs and Symptoms

There are early and late stage symptoms of hemorrhagic fever that result from exposure to Ebola Virus.  First signs might include headache, fever, chills, nausea, sore throat, malaise (def), and/or diarrhea.  Late stage symptoms might include external bleeding from the eyes, ears, nose, mouth, and rectum; depression; conjunctivitis (def); genital swelling; rash over the body that may contain blood; feeling of pain in skin; seizures; coma; delirium.  Although earliest cases all presented with bleeding externally, in more recent cases this does not always occur.  Shock is usually the cause of death, not loss of blood.

Prevention and Treatment          

There currently is no known cure for Ebola Hemorrhagic Fever.  In fact it is not always understood why one patient may survive exposure to the virus and another may not.  In addition, anti-viral drugs do not work well on Ebola.  Treatment is to basically prevent dehydration by providing fluids and replenishing any lost blood.  Health care providers are focused on what they can do to prevent the onset of shock and deal with any complications that may arise. 
    
It is also difficult to look at the Ebola Virus from a prevention stand point as the source is unknown.  The only thing that can be done is to handle an outbreak in the proper way to isolate and prevent its spread.  Most important is early diagnosis.  This can prevent any unwanted and unprotected exposure.  Health care workers can employ various barrier measures such as masks, gloves, etc.  Also, patients who survive exposure can carry the disease for weeks and should be isolated properly.  And with an incubation period of 2-21 days after exposure, patients need to be monitored accordingly.
    
With the lack of vaccine or drug treatments, research is currently being done.  Combination drug treatments have been tested in laboratories on primates and have shown some success.  However one combination drug that works for one species may not work on another.  Because of Ebola’s effect on the blood coagulation pathway, that is leading the body to abnormal clotting and eventually hemorrhaging, some scientists are focused on how to change the body’s reaction to the virus.  Another approach is in trying to develop an anti-viral that would work on Ebola, as well as other viruses that may not currently respond to anti-viral drugs.  Scientists have recently begun targeting the envelope (def) that surrounds the viral genome (def) and capsid (def) of viruses such as Ebola, HIV-1, influenza A, and others.  LJ-001, as it is known, has been successfully used in the laboratory by attaching to the viral membrane and blocking its fusion with the host cell membrane.  Of course many years of testing and further studies are needed before it is a viable option for humans.   

Works Cited

Baker, Pam. "Breakthrough Could Lead to Cure for AIDS and Other Deadly Viruses." Tech News World
(2010). Ecommercetimes. ECT News Network, 4 Feb. 2010. Web. 14 Apr. 2010.

Fox, Stuart. "Compound LJ001 Acts Like Antibiotic Against Viruses." Popular Science. Bonnier Corporation, 2 Feb. 2010. Web. 14 Apr. 2010.

Information on Ebola Virus. Atlanta: CDC Special Pathogens Branch, 2009. Health Topics A-Z. Web. 14 Apr. 2010.

King, John W. "Ebola Virus." EMedicine. Medscape. WebMD, 2 Apr. 2008. Web. 14 Apr. 2010.

Vorvick, Linda, and Jatin M. Vyas. "Ebola Hemorrhagic Fever." A.D.A.M. Medical Encyclopedia. Medline Plus, 28 Aug. 2009. Web. 14 Apr. 2010.

Wikipedia. Wikimedia Foundation, Inc., 3 Mar. 2010. Web. 14 Apr. 2010.