The document provides information on the Ebola virus. It discusses that Ebola virus disease first appeared in 1976 in simultaneous outbreaks in Sudan and Zaire. It belongs to the filovirus family and species Zaire ebolavirus which caused the 2014 West African outbreak. The virus infects and kills its host efficiently by attacking the lymph nodes and bloodstream. While there is no proven cure, several vaccine candidates and antiviral treatments are being studied.

1. EBOLA VIRUS
BY- SHREYA AHUJA
ROLL NO. 11

3. • The virus family Filoviridae includes 3 genera: Cuevavirus, Marburgvirus, and Ebolavirus.
• Three species of Ebolavirus have been found so far, Bundibugyo ebolavirus, Zaire ebolavirus, and Sudan ebolavirus.
The virus causing the 2014 west African outbreak belongs to the Zaire species
• Ebola virus disease (EVD) first appeared in 1976 in 2 simultaneous outbreaks, one in Sudan, and the other in Zaire.
The latter occurred in a village near the Ebola River, from which the disease takes its name.
• In 1989, Veterinary staff in Virginia had first noticed numerous deaths in monkeys in one animal room and suspected
it to be Simian Hemorrhagic Fever (SHF). Tested samples were shown to contain a filovirus in high concentrations
along with SHF virus. This was later identified as a strain of the Ebola virus and was clearly responsible for much of
the morbidity.
• A recent study suggests that the virus may have passed into its first human victim, a child, from a small insect-eating
bat, an animal so diminutive that it is hunted by children but not by adults.

5. • Ebola virions are pleomorphic, appearing as either long
filamentous forms or in shorter U-shaped or circular
configurations.
• Virions have a uniform diameter of 80nm and vary greatly in length
(up to 14,000nm)
• They are composed of a helical nucleocapsid, a membrane
envelope derived from host cell plasma membrane, and a surface
projection layer composed of 10nm long peplomers.
• Ebola virus infectivity is stable at room temperature and is
destroyed in 30mins at 60°C. Infectivity can also be destroyed by
ultraviolet and gamma radiation, lipid solvents, and phenolic
disinfectants.

8. • The nucleocapsid in the center of the virion is made of a RNA wound helically with the proteins NP,
VP35, VP30, and last but not least L. The viral proteins VP40 and VP24 are found in the viral
tegument or the area between the envelope and nucleocapsid.
• Each virion of Ebola virus has a single stranded, negative sense RNA linear genome. There are
seven sequentially arranged genes contained in a single molecule approximately 19kb in length.
• The virus codes for seven structural proteins and one non-structural protein.
• Having a negative sense polarity, the virus’ RNA structure begins in the 3’ position and ends in the
5’ position. Following the 3’ position is a non-transcribed region known as the leader.

9. • The transcriptional signals of Filoviruses contain a common sequence, 3’UAAUU at the 5’ end of start
sites and 3’end of stop sites, a property that is so far unique to these viruses.
• The 5’end of the genome has a transcriptional stop (Polyadenylation) site. Termination of
transcription occurs at a series of five or six U’s where repeated copying by the polymerase results in
addition of long poly (A) tails to the transcripts.
UAAUUCUUUUU

10. Processing of GP protein

11. • Glycoprotein: It makes up the virion surface spikes that mediate virus entry into susceptible host cells
through receptor binding.
• VP40: This protein is believed to have a matrix protein function and maintains viral structure integrity. It
may facilitate the budding of the virion at the plasma membrane by facilitating interaction between
nucleocapsid proteins (NP and VP30) and envelope proteins (GP and VP24)
• VP24: Membrane associated protein which may function in the un-coating of the virion during infection.
• Nucleoprotein: It is the primary structural protein associated with Filovirus nucleocapsids. Interacts with
matrix protein during virus packaging and assembly.
• VP30 (Also known as minor nucleoprotein): It is tightly bound in the nucleocapsid and it can bind to the
RNA non-specifically. It is involved in transcription activation and re-initiation.
• Polymerase (L protein): It is the RNA Dependent RNA Polymerase required for transcription and
translation. Caps and poly-adenylates mRNA’s. Uses +ssRNA as templates for synthesizing copies of –
ssRNA.
• VP35: It acts as a cofactor for L polymerase. It is responsible for binding a host double stranded RNA and
inhibiting the host cells alpha/beta interferon

13. Host Entry – Through mucus
membranes or directly into
blood
Adsorption – Glycoprotein binds
cellular receptor (Lectin protein)
Endocytosis
(Macropinocytosis)
Late Endosomal Events –
Acidification activates Cathepsin B
and L
Protein synthesis – Synthesis
of structural and non-
structural proteins
Genome Replication
GP Modification in ER and Golgi and
transport in vesicles to plasma membrane
Assembly and
release by budding

14. The virus isn't what ends up killing you. It's your own immune system

15. Fever, headache and chills are caused by an overt cytokine response to
virus
Bleeding from the eyes, ears and mouth is caused by loss of vascular
integrity due to endothelial cell death and dysregulation of clotting factors
because of hepatocellular necrosis
Impaired kidney and liver function due to death (apoptosis) of renal and
hepatic cells
Virus evades the immune response by causing rapid destruction of
lymphoid tissue, including B and T cells, and disrupting the interferon
response
Watery diarrhea, nausea, vomiting and abdominal pain is due to necrotic
infection of the gastrointestinal tract - loss of the ciliated cells required for
absorption of nutrients - gastrointestinal bleeding
Muscle pain and weakness is likely due to the cytokine response to the
virus
Haemorrhagic rashes, bruising, and oozing caused by loss of vascular
integrity due to endothelial cell death and hepatocellular necrosis

16. The methods used are:
 ELISA
• Ebola Virus lysates used
• Four dilutions – 1/4, 1/16, 1/64, 1/256
 RT-PCR
• Primer used: 5’-GAGACAACGGAAGCTAATGC-3’
• 30 min at 50°C to allow RT followed by 2 min at 94°C to allow enzyme inactivation and denaturation. This is
then followed by 38 cycles of denaturing at 94°C for 30 s, annealing at 50°C for 30 s, and elongation at 68°C for 1
min.
 PLAQUE ASSAY
• Dilutions of virus are adsorbed to a monolayer of cells and incubated. The monolayers are overlaid with 1%
agarose and the virus plaques were counted after incubation
 NUCLEOTIDE SEQUENCING
• DNA products purified after PCR are sequenced and analyzed
 REDS – Rapid Ebola Detection Strips
• Nanoparticles linked to antibodies which recognize Ebola antigen

17.  SUB-UNIT VACCINES
• EBOV genes inserted into a DNA plasmid can be injected directly into a patient’s muscle, where expression of the
antigen can elicit an immune response to the corresponding virus particle.
• GP, NP, VP40, VP35 used
• Low survival rates
 VECTOR BASED VACCINES
• Viruses can be used as vaccine vectors when genes encoding antigens of EBOV are inserted and expressed from the
viral carrier.
• Vaccinia Virus, Adenovirus, Vesiculovirus, VEE virus have been used
• Adenoviruses have shown success in non-human primates and are undergoing phase 1 trial
 HIV DRUG used out of sheer desperation
• Lamivudine
• Dr. Gobee Logan, treated 15 Ebola patients with this drug and 13 survived
• Lamivudine is a Cytidine analog reverse-transcriptase inhibitor
• The HIV-1 RT enzyme recognizes and incorporates Lamivudine Triphosphate in the place of Cytidine Triphosphate.
• Cytidine (C) is present in both DNA chains (base pairs GCAT) and RNA chains (GCAU)
• Lamivudine competes with Cytidine as a nucleic acid base for Ebola RNA Replicase in human macrophages
There is no proven cure for Ebola at this time

18.  FAVIPIRAVIR
• 6-fluoro-3-hydroxy-2-pyrazinecarboxamide is an antiviral drug that selectively inhibits the RNA-dependent RNA
polymerase
• The drug was found effective in patients with low to moderate Ebola infection, however it had no effect in people
who were heavily infected
 TKM-EBOLA
• This drug is based on RNAi therapy
• Targets viral proteins – L, VP35 and VP24
• Deliver the siRNA through stable nucleic acid lipid particles (SNALPs)
• It has been granted emergency use approval by the US Food and Drug Administration
 HEMOPURIFIER
• It filters the blood to remove virus particles when connected to a dialysis machine.
• The United States Food and Drug Administration (FDA) granted approval in January 2015 for a clinical trial of a
device
 TETRANDRINE
• Modifies pore channels in the host cell membrane needed for Ebola infection
• Most potent compound tested with low cytotoxicity

19. What makes Ebola so different than other viruses is it’s ability to attack and overcome its
host so efficiently. It quickly migrates throughout the lymph nodes and the blood stream to
infect the parenchyma of most organs. The only cells it will not infect are skeletal/cardiac
muscle and bone.
Although this is a truly morbid subject, Ebola serves as one of the most efficient viruses in
nature. So efficient and so deadly, that frequently contamination wipes out the host
population before the virus can spread to a wider demographic.
One of natures most deadly killing machines!!

20. • http://www.who.int/mediacentre/factsheets/fs103/en/
• http://news.nationalgeographic.com/news/2014/12/141230-ebola-virus-origin-insect-bats-meliandou-reservoir-
host/
• http://www.operonlabs.com/?q=node/7
• http://www.uptodate.com/contents/clinical-manifestations-and-diagnosis-of-ebola-virus-disease
• https://www.internationalsos.com/ebola/index.cfm?content_id=442&language_id=ENG
• http://www.npr.org/blogs/goatsandsoda/2014/08/26/342451672/how-ebola-kills-you-its-not-the-virus
• Jonathan S. Towner et al (2004) Rapid Diagnosis of Ebola Hemorrhagic Fever by Reverse Transcription-PCR in an
Outbreak Setting and Assessment of Patient Viral Load as a Predictor of Outcome. J. of Virology. 78:8,4330-4341
• Jason S. Richardson (2010) Recent advances in Ebolavirus vaccine development. Human Vaccines 6:6, 439-449
• Fields Viology

21. THANK YOU!