Ebola - Class 12 biology investigatory project

SOURAV PANDA | Roll No - 40 |

BIOLOGY INVESTIGATORY PROJECT ON RECENT DISEASES - EBOLA

Ebola Proteins

• Initial symptoms are nonspecific - may include fever, chills, myalgias, and malaise.

Symptoms of Ebola

• Patients can progress to gastrointestinal symptoms:

develop

– severe watery diarrhea, vomiting, abdominal pain

nausea,

• Other symptoms: – chest pain, shortness of breath, headache or confusion, conjunctival injection, hiccups, seizures, and cerebral edema

• Bleeding not universally present but can manifest later as petechiae, ecchymosis/ bruising, or oozing. Frank hemorrhage less common. •

Some develop maculopapular desquamate.

diffuse rash

erythematous that can

Source: Centers for Disease Control and Prevention. http://www.cdc.gov/vhf/ebola/hcp/clinician-information-us-healthcare-settings.html Accessed Oct. 14, 2014

Diagonosis Of Ebola •

• Diagnosing Ebola can be difficult at first since early symptoms, such as fever, are nonspecific to Ebola infection. • However, if a person has the early symptoms and has had contact with Ebola they should be isolated and public health professionals notified. •

Samples from the patient can then be collected and tested to confirm infection.

Treatment of Ebola •

• There are no approved treatments available for EVD. • Clinical management focus - supportive care of complications: – Hypovolemia , electrolyte abnormalities, hematologic abnormalities, refractory shock, hypoxia, hemorrhage, septic shock, multi-organ failure, and DIC. • Recommended care includes: – volume repletion – maintenance of blood pressure (with vasopressors if needed) – maintenance of oxygenation – pain control – nutritional support – treating secondary bacterial infections and pre-existing comorbidities • Among patients from West Africa, large volumes of intravenous fluids have often been required to correct dehydration due to diarrhea and vomiting. •

Several investigational therapeutics for Ebola virus disease are in development. There are no approved vaccines available for EVD. Several Source: Centers for Disease Control and Prevention. http://www.cdc.gov/vhf/ebola/hcp/clinician-information-us-healthcare-settings.html investigational Ebola vaccines are in Accessed Oct. 14, 2014

Index 

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Ebola: Upcoming Future Epidemic

Epidemiology

Ebola Subtypes Molecular Structure And Characteristic Features Transmission Of Ebola Symptoms Of Ebola Diagnosis Of Ebola Treatment Of Ebola Checklist For Infected Ebola Virus Disease(EVD) Sequence Of Putting On Personal Protective Equipment(PPE)

Ebola: Upcoming Future Epidemic The Ebola virus is a lipid enveloped virus in the family Filoviridae. Members of this family also include Marburg, Lassa, and other viruses that cause hemorrhagic fever, a group of illnesses that damage the vascular system and in severe cases, lead to bleeding under the skin, in internal organs or from body orifices (e.g. mouth, eyes and ears)1. Infection with the Ebola virus is now referred to as: Ebola virus disease (EVD)2. There is a diagnostic test to determine if the patient has EVD. There is no current FDA approved effective medication or treatment for those who become infected with

Ebola other than supportive hydration, electrolyte balancing and oxygen. The death rate of those infected is between 5090%. There is no vaccine or preventative treatment.

TRANSMISSION OF EBOLA Person-to-person transmission occurs by very close personal contact with an infected individual or with their body fluids during the late stages of infection or after their death 3,4. During the care of an infected individual, spread of the virus can occur through contact with infected body fluids on the patient, on their clothes or bedding, on surfaces such as bedrails, side tables, the floor, or on reused unsterilized syringes, needles, thermometers or other viruscontaminated medical equipment. Humans may also be infected by handling sick or dead

non-human primates and are also at risk when handling the bodies of deceased humans in preparation for funerals 5,6. Virus containing body fluids from individuals infected with the Ebola virus:  Blood  Breast milk  Organs and tissues  Saliva  Semen  Stool  Sweat  Urine  Vaginal secretions  Vomit  Amniotic fluid (possibly)

Note: Ebola virus has been isolated from semen 61 days after the initial symptoms of infection appear. Transmission through semen has occurred 7 weeks after clinical recovery Incubation period: It requires 2 to 21 days (more often 4-9 days) before symptoms of infection occur. The infected individual is not contagious until symptoms appear.

Hemorrhage begins to present 4-5 days after general symptom onset Survival outside the body: The virus can survive and remain infective in liquid or dried material at room temperature for a number of days 10 or at 39°F (4°C) for several days, and is indefinitely stable at -70°C. Infectivity can be preserved by lyophilization (freeze-drying)

How Ebola enters the body: Intact skin is a barrier, but scratches, cuts (large or tiny), rashes, and abrasions, ruin the barrier integrity and become routes for viral entry. Additionally, Ebola virus can enter the body through mucosal tissues after being deposited by contaminated fluids through physical contact, splashes, splatters, sprays, or possibly aerosols. Mucosal tissues include the eyes, mouth, throat, lungs inside of nose, vaginal tissues, intestines, and urinary tract

• Most common symptoms reported during current outbreak: – fever (87%) – fatigue (76%) – vomiting (68%) – diarrhea (66%) – loss of appetite (65%)

• Patients with fatal disease develop more severe clinical signs early during infection and die between days 6 - 16 of complications (mean of 7.5 days). • In non-fatal cases, patients may have fever for several days and improve, around day 6. • The case fatality proportion in West Africa is about 71%

•

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Ebola Subtypes Ebola-Zaire

(ZEBOV)

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Ebola-Zaire

(ZEBOV)

Ebola Ebola-Sudan (SEBOV) Sudan  Ebola Ivory(SEBOV) Coast (ICEBOV)  Ebola Ebola-Reston Ivory-Coast (REBOV) (ICEBOV) Ebola-Reston (REBOV) 

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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

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– 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

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– 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

Epidemiol ogy

First Known Case Of August 26, 1976 in Yambuku, a town in the Ebola north of Zaïre. A 44-year-old school teacher returned from a small hike. His went to the doctor and because of his high fever they gave him a quinine shot which is good against malaria.

A week later, he had uncontrolled vomiting, bloody diarrhea, trouble breathing and then bleeding from his nose, mouth, and anus. 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 --