Ebola Virus Hemorrhagic Fever

Ebola Virus

• Hemorrhagic Fever

Outbreaks

• 1976- First Major Outbreak (ZEBOV)

• 1976- Sudan (SEBOV)

• Occur Sporadically

• www.cdc.gov for more information

Where does Ebola hide?

• 2002- Fruit Bats

• Antibodies against Ebola

• Ebola Gene sequences in liver and spleen

• Fruit bats do not show any symptoms

• Best candidate to be the reservoir

• More research needs to be done

Geography

• The link between human infection by the Ebola virus and their proximity to primates is clear.

• -Outbreaks occurred in countries that house 80 percent of the world’s remaining wild gorilla and chimpanzee populations.

• - The outbreaks coincided with the outbreaks in wild animals.

• - The same distinct viral strains were isolated in animal carcasses and in the bodies of those who handled those carcasses.

• - These outbreaks were preceded by an abnormally large death in wild Gorilla populations.

Clinical Observations

• Incubation period: 2-21 days

• Stage I (unspecific):

• -Extreme asthenia (body weakness)

• -diarrhea, nausea and vomiting, anorexia

• abdominal pain

• - headaches

• - arthralgia (neuralgic pain in joints)

• - myalgia (muscular pain or tenderness), back pain

• - mucosal redness of the oral cavity, dysphagia (difficulty in swallowing)

• - conjunctivitis.

• - rash all over body except in face

• ** If the patients don’t recover gradually at this point, there is a high probability that the disease will progress to the second phase, resulting in complications which eventually lead to death (Mupapa et al., 1999).

Stage II (Specific):

• Stage II (Specific):

• - Hemorrhage

• - neuropsychiatric abnormalities

• - anuria (the absence of urine formation)

• - hiccups

• - tachypnea (rapid breathing).

• ** Patients who progressed to phase two EHF almost always die. (Ndambi et al., 1999)

• Late Complications:

• -Arthralgia

• - ocular diseases (ocular pain, photophobia and hyperlacrimation)

• - hearing loss

• - unilateral orchitis( inflammation of one or both of the testes)

• ** These conditions are usually relieved with the treatment of 1% atropine and steroids

Epidemiology

•  Ebola Hemorrhagic Fever was first found in 1976

• It struck two countries within that year

• a.  Sudan – in a town called N’zara

• b.  Zaire, now known as the Democratic Republic of Congo

•   In these two instances the mortality rate was between

• 50 –90%

• Following those epidemics, Ebola hit Africa in many other instances the worst yet being in the year 2000 when it struck Uganda infecting more than 400 people.

Transmission

• contracted through contact of any infected individual’s body fluids

Controlling the spread of Ebola

• a. Hospitals must follow precautionary methods, such as: 

• 1.      wearing gloves

• 2.      isolating infected individuals

• 3.      practicing nurse barrier techniques

• 4.      proper sterilization and disposal of all equipment

• b.  Burials must be done correctly

• 1.      no washing or touching carcass

• 2.      put into body bags and bury outside city

• c. Report any questionable illness to officials                   

Ebola Subtypes

• Ebola-Zaire

• (ZEBOV)

• Ebola-Sudan (SEBOV)

• Ebola Ivory-Coast (ICEBOV)

• Ebola-Reston (REBOV)

MOLECULAR STRUCTURE

• Characterization of the virus

• Order: Mononegavirales
• Family: Filoviridae
• Genus: Ebolavirus
• Species: Ebola-Zaire, Ebola-Sudan, Ebola-Cote d-Ivoire, Ebola-Reston

• Morphology under electron microscope

• filamentous, enveloped RNA virus
• approx. 19 kb in length (1 kb = 1000 RNA
• bases/nucleotides) or 60-80 nm in diameter
• single-stranded, linear, non-segmented
• negative-sense RNA (encoded in a 3’ to 5’ direction)
• appears to have “spikes” due to glycoprotein on
• outside membrane

Structure of Ebola genome and proteins

• Structure of Ebola genome and proteins

• Transcribed into 8 sub-genomic mRNA proteins: 7 structural and 1 nonstructural
• 7 structural proteins:
• nucleoprotein (NP)
• 4 viral/virion proteins (VP35, VP40, VP30, VP24)
• glycoprotein (GP)
• RNA-dependent RNA polymerase (L protein)
• NP, VP35, VP30, L protein: required for transcription & replication
• VP40, GP, VP24: associated with the membrane

Proteins

Ethics

• Biogeograophical Ethics is defined as motivation based on ideas of right and wrong when dealing with the geographical distribution of animals and plants.

• This concept of can be used to explain the world’s shockingly small response to the Ebola Virus.

• Because there was little travel to that region by people of more developed countries, there was not much economic drive for a vaccine, treatment, and aid in prevention.

Bioterrorism

• Since the September 11 bombings in the United States, the locality of this virus has become less isolated as the threat of bioterrorism looms large.

• The Ebola virus is now on the “A” list for hopeful vaccination development.

• Experiments have even been formed to show how Ebola can be used as a bioterror agent.