Ebola virus

   Ebola
Picture courtesy of wikipedia.com

    The Ebola virus is a very deadly disease.  It causes Ebola hemorrhagic fever which is classified within the taxonomy of group V under the order Mononegavirales, family Filoviridae, and genus Ebolavirus (wikipedia).  The pathogenesis of the Ebola virus can be broken down into three categories including:

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    Reservoir: The reservoirs for the Ebola virus are not quite known.  "Filoviruses do not persist in experimentally infected nonhuman primates; therefore, nonhuman primates are likely not the natural reservoir (cdc)." 

    Mode of Transmission: Because the reservoirs for the Ebola virus are unknown, this makes the mode of transmission for the virus harder to describe.  It is well known that the virus can pass through zoonosis.  “Like humans, these species are probably infected when direct or indirect contact is made with the natural host (cdc).”  “Among humans, the virus is transmitted by direct contact with infected body fluids, or to a lesser extent, skin or mucus membrane contact.  There is very limited evidence for human-to-human airborne transmission of any reported epidemics (wikipedia).” 

    Tissue tropism: The tissue tropism of the Ebola virus is extremely vast.  “Filoviruses replicate well in a wide range of organs and cell types such as hepatocytes, epithelial cells, fibroblasts, fibroblastic reticular cells and adrenal cortical cells (wikipedia).” 

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    Epidemiology: Lastly, the epidemiology of the Ebola virus is extremely deadly.  It is responsible for sever outbreaks of Ebola hemorrhagic fever ranging from with mortality rates ranging from 23% to 88%.  Some studies say that the mortality rates are ranging severely high from 80%-90% (wikipedia).  The extent of the mortality rate depends on the location at which the disease was transmitted.

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    Signs and Symptoms: The signs and symptoms associated with the Ebola virus are actually associated with Ebola hemorrhagic fever.  Symptoms tend to appear quite suddenly yet are usually mistaken for other infectious diseases such as Malaria, typhoid fever, dysentery, influenza, or various other bacterial infections.  They include high fever, severe headache, muscle, joint, or abdominal pain, severe weakness, exhaustion, soar throat,  nausea, and dizziness.  As the virus continues to replicate, symptoms tend to become more sever.  They progress into diarrhea, dark or bloody feces, vomiting blood, red eyes due to distention and hemorrhage of the sclerotic arterioles, petechia, maculopapular rash , and purpura (wikipedia).  Sequelae that can occur are, "hypovolemia, tachycardia, organ damage (especially the kidneys, spleen, and liver) as a result of disseminated systemic necrosis, and proteinuria.  Occasionally, internal and external hemorrhage from orifices, such as the nose and mouth may also occur, as well as from incompletely healed injuries such as needle-puncture sites.  The Ebola virus can infect platelets and disrupting clotting.  Fewer than 50% of patients will develop hemorrhaging” (wikipedia).  Although, the virus is highly contagious and infected skin cells can be shed for up to 61 day, thankfully there is no latent organisms that remain.  This rules out the possibility of reactivation.

      Diagnosis: Diagnosis of the Ebola virus and Ebola hemorrhagic fever can be very difficult without diagnostic testing.  The clearest sign would be the travel patterns of the patient.  There have been noted outbreaks and transportation of the virus from places such as Sudan as well as Zaire.  “However, a history of exposure to tropical African forests is more frequent in patients with Ebola than is a history of working within cities in the same region (wikipedia)”.  Without looking at travel patterns of the patient as well as diagnostic testing, there would be no other way to determine the presence of the Ebola virus.

 

EBOLA

Picture from: Medline Plus available at : http://www.nlm.nih.gov/medlineplus/ency/imagepages/17160.htm

 


Test
Reference Range
Expected Results
Screening Test/Confirmatory Test
ELISA detecting IgM
45-150 mg/dL negative
Confirmatory
ELISA detecting IgG 7.0-16.0 mg/dL
negative
Confirmatory
Electron microscopy none
negative
Screening
Indirect fluorescent antibody test none
negative
Screening
Antigen-detection ELISA none
negative
Confirmatory

 


           Extra information about tests from: http://www.emedicine.com/med/byname/Immunoglobulin-M-Deficiency.htm and http://www.xs4all.nl/~ednieuw/IgGsubclasses/subkl3.htm

      Treatment and Prevention: Lastly, the recommended preventions are to stay away from such tropical rain forests where natural reservoirs of the virus are unknown.  Successful vaccines have yet to be reported even though they are a work in progress.  So far, recombinant Vesicular stomatitis virus or a recombinant Adenovirus carrying the Ebola spike protein on its surface has fully protected a group of monkeys.  Treatments are very weak for such a strong and contagious disease.  They include “minimizing invasive procedures, balancing electrolytes, replacing lost coagulation factors to help stop bleeding, maintaining oxygen and blood levels, and treating any complicating infections” (wikipedia).

 

 

 References:


      CDC. Emerging Infectious Disease. Reemergence of Ebola Virus in Africa [serial online] 1995; July-Sept.  Available at: http://www.cdc.gov/ncidod/eid/vol1no3/sanchez.htm.

eMedicine. Ebola Virus. eMedicine from WebMD.  Available at: http://www.emedicine.com/MED/topic626.htm.

Wikipedia. Ebola. Wikipedia the free encyclopedia.  Available at: http://en.wikipedia.org/wiki/Ebola.

 

The Ebola Virus at eMedicine

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