Ebola

Classification:

Enveloped -ssRNA.

Ebola Genus:

Filoviridae.

Where did the two simultaneous Ebola outbreaks take place in 1976?

South Sudan and the Democratic Republic of the Congo.

Where was the first recorded case of Ebola?

The village of Yambuku in the Zaire province of the Democratic Republic of Congo.

What was the first recorded case of Ebola thought to be?

Malaria.

How did the virus spread from the first recorded case to others?

To treat Mabalo Lokela, chloroquinone was injected, the needles were not properly sterilized and so other patients the needles were used on got infected.

What did Mabalo die of?

Hemorrhagic shock and fluid loss.

Where was the first actual outbreak of Ebola?

South Sudan, it was called the Sudan Virus (SUDV).

What did Dr. Muyembe do?

He was the first to obtain a blood sample containing Ebola virus taken by a Yambuku nun who had been administering vitamin shots to pregnant women.

What did Dr. Piot do?

He isolated the virus from the first blood sample and the disease was named the “Ebola virus” after the Ebola river.

Ebola incubation time:

Typically 4-10 days, about 5% of cases may take more than 21.

Ebola flu-like symptoms:

Fever (above 38.3^oC, or 101^oF), weakness, joint and muscle pain, lack of appetite, headache, and sore throat.

Severe Ebola symptoms:

Nausea, vomiting, diarrhea, abdominal pain, dehydration, and maculopapular rash (50% of cases).

Ebola 5-7 after symptom offset:

50% experience internal and/or external bleeding.

What do all Ebola patients suffer from during the symptomatic period?

Decreased blood clotting capabilities.

Why can the diagnosis of Ebola be difficult?

Symptoms are similar to other hemorrhagic fevers common to Africa such as Dengue, Malaria, and Crimean-Congo Hemorrhagic Fever (CCHF).

What is one of the most common diagnostic methods in field hospitals used to confirm Ebola diagnosis?

RT-PCR (real time).

What type of Ebola test was developed in 2015?

A rapid antigen test effective at correctly confirming 92% of positive infections, and able to rule out 85% of individuals not infected.

When do patients start to recover from Ebola (if they live)?

Between 7 and 10 days after the start of symptoms.

When do patients usually die from Ebola?

Between 6 and 14 days after symptoms.

What are possible long-term complications of Ebola?

Liver inflammation, ongoing joint and muscle pain, continued weakness, and problems with vision.

What bodily fluids can Ebola be transmitted through?

Blood, feces, sweat, vomit, mucus, tears, urine, semen, breastmilk, and saliva (in very rare cases).

What points of entry does Ebola typically use?

Open cuts/wounds, eyes, nose, mouth, abraded tissue, and via sexual intercourse.

Can contaminated needles and medical equipment pose a serious risk to patients and health care workers?

Yes, worse in poorer areas.

Can the bodies of deceased Ebola patients continue to be infectious?

Yes.

What are the first cells that Ebola targets?

Macrophages, monocytes, dendritic cells, and blood vessel endothelial cells.

When can infection of blood vessel endothelial cells occur in Ebola infection?

As early as 3 days.

When can Ebola replicate in lymph tissue and spread to the rest of the body to cause systemic infection?

Once drainage to lymph nodes occurs.

What are Ebola’s viral characteristics?

Helical, enveloped, (-)ssRNA.

How big are Ebola virions?

Typically about 80nm in diameter.

How is the envelope acquired from host cell membranes?

Via budding.

What is the Ebola envelope studded by?

Glycoprotein spikes.

What do Ebola’s glycoprotein spikes do?

They embed into host cell membranes and anchor the membrane to the virus during maturation, facilitating the theft of the lipid bilayer.

What does the Ebola viral genome have?

A long 5’UTR and a long unadenylated 3’UTR.

What does the Ebola genome lack?

An IRES cloverleaf.

What does the Ebola genome encode?

7 structural proteins and one non-structural protein.

What don’t we know about Ebola?

How it accesses ribosomes, but research has shown that Ebola viral RNA does reduce host translation and is capable of accessing ribosomes for translation of its proteins.

What is the nucleocapsid?

It wraps the genome for protection from nucleases and innate immunity and is part of the Ebola capsid.

What do Ebola glycoprotein spikes bind to?

Two host cell receptors, NPC1 and TIM-1.

What is NPC1?

A cholesterol importer channel.

What is TIM-1?

A T cell receptor that signals to the body that an apoptotic cell is ready to be cleared away, typically found in mucosal tissues.

What are major targets of Ebola infection that TIM-1 can also be found in?

The cornea, trachea, and conjunctiva.

What can Ebola do once it enters the cell?

Shed its envelope, release its genome, and begin manufacturing virions in the cytoplasm of host cells.

How does Ebola progress into a potentially lethal disease state?

By evading host immunity for several days.

What is Viral sGP?

A cleavage product of the glycoprotein genome product.

What does Viral sGP do?

It creates a dimer complex that disrupts neutrophil cell signaling, delaying innate immune response and thus adaptive immunity signaling.

What do Viral VP24 and VP35 do?

Block IFN signaling by blocking STAT1 and binding and inhibiting the function of IFN-b, causing the cell to fail to form the IFNab complex.

What is the mortality rate of Ebola infections in chimpanzees and gorillas?

Often 80%.

What is the likely non-primate reservoir of Ebola?

Bats.

Prevention and Management - Bushmeat:

Proper handling of bushmeat prior to consumption to prevent animal-human transmission.

Prevention and Management - Outbreak:

First line of defense is good hospital PPE and proper sanitation procedures.

Prevention and Management - Infected patients:

Proper isolation of infected patients and disposal and disinfection of bodily fluids, contaminated objects and clothing, and safe burial practices are essential to limit the spread.

Who has an increased risk of contracting Ebola?

Healthcare workers in affected countries.

Primary supportive care for Ebola:

Rehydration using IV fluids, nausea, vomiting, and pain management medications, and the application of blood products (transfusion, platelets, plasma, etc) to replace lost blood.

What are the two US FDA approved Ebola medications that assist in clearing the virus from infected patients?

Atoltivimab and ansuvimab.

Who created the first live attenuated Ebola Virus vaccine?

Scientists working for the Public Health Agency of Canada.

Has there ever been an outbreak of Ebola outside of Africa?

No, but there have been concerning incidents in the United States, Spain, and Scotland.