About Ebola

by LiamBean

The Facts and figures on Ebola Disease Virus, its lethality, and just how contagious it actually is.

This West African virus is big news in the United States with a lot of associated panic. This article will attempt to dispel rumor with truth, assumptions with fact, and speculation with actuality.

Though Ebola Disease Virus was discovered in 1976 in the Republic of Congo, it is not well known in the U.S.

News Coverage

November 11, 2014 (first Published October 24, 2014)

There is near constant news coverage of Ebola, or Ebola Virus Disease, since the first case made its way to the United States.

Ebola, named after a river near the site of its discovery, was first isolated as a new viron* in Zaire in 1975. In that year, there were three hundred eighteen (318) confirmed cases with a mortality rate of sixty-eight percent (68%) or two hundred eighty (280) confirmed deaths. Only thirty-eight of those confirmed cases survived.

As of this date (above) nine people in the U.S. have contracted the virus. Seven have been released back home after being deemed clear of the virus, one is undergoing treatment (in New York), and one has died.

Though it this not confirmed, it is believed that Ebola originated in fruit bats and was transferred to humans via the consumption or preparation of "bush meat" or by consuming food that was peppered by bat droppings.

This article will cover what is known about the virus, from various sources, and attempt to dispel rumor and the resulting fear.


* a viron is a complete virus particle

Relevant Data

History
Ebola, or Ebola Virus Disease, first recognized in 1976 in Zaire, Democratic Republic of Congo. It was co-discovered by Peter Piot. Piot sent a blood sample from an infected nun when he could not identify what was causing her illness. Once the viron was identified, Piot returned to Zaire where he and his team were instrumental in halting the disease after three months and three hundred deaths.

Signs and Symptoms
Ebola is not infectious unless the human host is displaying symptoms of the infection. Those symptoms include fever, headache, sore muscles and joints, and sore throat. As the illness progresses, the host can then display vomiting, diarrhea, and stomach pain.

In rarer instances Ebola disease can cause rashes, red eyes, hiccups, and internal & external bleeding.

If an exposed person contracts the disease symptoms will become apparent after two to twenty-one* days. After the twenty-one day incubation period, if no symptoms are present, then the person being watched is not at risk of contracting or displaying the symptoms of Ebola.

Transmission Vectors
A vector is an intermediate source or host to the virus. A vector is typically an animal that humans come into contact with. Initially, it was thought that Ebola was contracted by eating gorilla meat procured in the wild. It is now thought that bats carry the virus, without being affected by it, and that "bush meat" in the form of wild caught gorilla that have come into contact with bat droppings is the true source of the viron.

Other animals that can serve as vectors include chimpanzee, gorilla, forest antelope, and monkey all of which can have or might have eaten items laced with bat droppings.

Once a human has become infected and is displaying symptoms, others can contract the disease from the sufferer via bodily fluids. This includes, blood, sweat, tears, saliva, snot, and runny stool. Semen also contains the viron, where it seems to linger the longest.

Those at highest risk of contracting the disease are health workers who tend to those already infected.

* Piot found that if people exposed to the virus did not display symptoms after fifteen days, they were not going to contract the disease. An additional seven days was added to be safe.

Infections in Africa

From 1976 until the date at the top of this article, there have been approximately four thousand cases of Ebola Virus Disease with twenty-four hundred fatalities. Most of these have occurred in poorer regions of Africa where health care can be sub-standard to non-existent.

Many of the cases contracted in Africa came about when family members prepared their dead for burial by washing and preparing the body of the deceased. It is also a virtual certainty that EVD can be contracted from tainted bush meat.

Infections in the United States

So far, the only two cases of Ebola being contracted in the United States occurred when two nurses cared for a patient in Dallas. That patient later died. All other cases, so far, in the United States originated outside the country, most often in people coming from countries in West Africa.

Please note that the single patient who died, Thomas Eric Duncan, went to a hospital on September 25th, the day after he started running a fever. Duncan was sent home the same day. On September 28th, three days later, Duncan returned to the hospital when his fever did not break. It was not until September 30th that tests proved Duncan had the disease. Duncan was already at high risk of transmission when he checked into hospital. On October 8th, nine days after being diagnosed, Duncan died.

Note that Duncan was infectious from the time he began running a fever until the day he died. None of the forty-three other persons Duncan had contact with, other than the two nurses mentioned below, have contracted Ebola.

Protective gear was not worn by health workers until Duncan's diagnosis was made. This means Duncan was infectious and interacting with unprotected hospital personnel for two and a half days.

Nina Pham, one of the nurses who treated Duncan, tested positive for EVD* eleven days after Duncan was diagnosed. Amber Vinson, another nurse who cared for Duncan, was diagnosed with EVD sixteen days after Duncan was diagnosed.

Both nurses have now been declared virus free.

Dr. Martin Salia was admitted to the Nebraska Medical Center on the 15th of November 2014 and died on the 17th of November that same year. Hospital reports indicate that Dr. Salia was already in critical condition upon admission to the hospital.

This means, so far, that the mortality rate of EVD in the U.S. is near 20%, with eight survivors out of ten infections.

Ebola in Africa

Since 1976, over four thousand people have contracted EVD, four hundred of which are health care workers. Of the four hundred health care workers, two hundred thirty-three have died.That's a fatality rate approaching 60%.

According to the World Health Organization, this is likely due to limited funds for equipment, improper use of protective equipment that is available, not enough trained medical personnel, and long working hours in isolation wards.

Ebola Immunity

Survivors of the disease carry antibodies which help the immune system recognize and fight off the disease.

Survivors are often encouraged to aid in health-care work due to their immunity. Plasma from these survivors has helped other infected people fight off the disease if given early enough. However that plasma must match the blood-type of the afflicted.

Ebola Cure

To date, the best means of fighting off the Ebola virus is from antibodies derived from the plasma of an Ebola survivor. However, this means that the patient receiving the plasma must be the same blood-type as the donor. So far, every patient receiving plasma has fought off the virus rapidly and successfully.

Though a vaccine that cleared Ebola from apes and monkeys was created nearly two years ago, the vaccine was never tested on humans due to funding limitations. This lack of funding, in turn, was likely due to the fact that the disease had not yet made it to the United States until this year. In the last month (October 2014) there have been renewed efforts to mount human trials for this vaccine.

See Ebola Vaccine for News

How Contagious is Ebola

Transmission is not possible unless the infected person is showing symptoms. Ebola spreads only through direct contact with body fluids. A cough from a sick person could infect someone who has been sprayed with saliva particularly if that saliva lands in the other person's eye, is inhaled, lands in an open cut or wound, or lands in the mouth.

Emory University Hospital in Atlanta also found that the viron is present on the surface of the skin of the afflicted once that person develops symptoms. Touching the sweat of a victim and then touching the mouth or other opening is enough to transfer the viron.

The Centers for Disease Control found that the virus can remain viable, and infectious, for a two or three hour period on dry surfaces like doorknobs, telephones, sink handles, and counter-tops. It can survive for two to three days in the wet environment of standing water.

Bleach solutions and ultra violet rays (sunlight) can kill the virus. This is true for all viruses.

Why is Ebola so Deadly

Ebola (blue) invading a cell (yellow)There are many reasons, not the least of which is the relative "newness" of the disease. The viron that causes EVD is quite large at fourteen hundred nanometers in length and seventy to ninety nanometers in diameter. Compare this to seventy to eighty nanometers for the rhino-virus, (the common cold) and Ebola Virus is quite large.

Every external part of an Ebola viron can attach to a cell. Because Ebola is so large it presents much more surface area to a cell, where it attaches and then invades the cell. Once invasion is complete the virus uses cell components to reproduce thus weakening or killing the infected cell. It then breaks out of the infected cell, and moves through the blood stream to infect other cells.

For this reason, rapid, whole body infection, happens quickly. In some cases, at the time of death, the infected individual can have as many as a billion Ebola virons per cubic centimeter of blood. Compare this to an HIV infection which may have as many as a billion viron particles in the five point five liters (5,500 centimeters) of blood.

EVD attacks all cells in the body, but can (depending on the patient) have an affinity for liver cells, the cells that line and seal blood vessels, and the cells that form muscles.

Viron Surface Area

Viron
Surface Area in nanometers
Rhinovirus
25,446
Ebolavirus
4,090,000

Relative Sizes in Nanometers

A nanometer is one billionth of a meter
Scale Item
0.1 Diameter of a hydrogen atom
0.8 Amino Acid
2 Diameter of a DNA Alpha helix
20 Ribosome
30 Rhinoviruses (cold)
80 Influenza (flu)
100 HIV
150 Small bacteria such as Mycoplasma
1400 Marburg / Ebola (length only)

Hemorrhagic Fever

As with all diseases, EVD can affect different people different ways depending on an individual's overall health and immune response. EVD may attack the cell lining of blood vessels including arteries. For these people, symptoms include bleeding from the mouth, eyes, and intestines. For people so affected, EVD causes blood to seep through those vessels into surrounding tissues. The result is pink or blood red whites of the eyes, bloody mouth, and blood in urine and stool. For this reason EVD was originally called Ebola Hemorrhagic Fever.

Only a small percentage of the infected respond this way. But looking for the presence of blood in the whites of the eye, in the mouth, or in urine or stool is one possible way to make an early diagnosis. For most others, "flu-like" symptoms are the best indicator.

Ebola Detection

December 4, 2014

Until recently, detecting Ebola Viron particles has taken the better part of a day in a laboratory setting.  This test is not designed to replace laboratory tests, but instead, allow health-care workers to implement treatment sooner while awaiting lab results.

The test can be conducted, with results, within fifteen minutes while in the field. As of this writing the test and protocol will be limited to Guinea will be conducted by researchers with the Pasteur Institute in Dakar, Senegal. Funding for the test and the trials are paid for by The Wellcome Trust and the UK government.

Not much more is known about this test, so far, however Wellcome Trust states that it is "briefcase" sized.

Ebola Vaccine

December 4, 2014

Dr. Anthony Fauci, director of NIH's National Institute of Allergy and Infectious Diseases, announced human trials of a newly created vaccine for EVD. The vaccine is the outgrowth of research that had begun more than ten years ago for treatment against Ebola-Zaire. Initially the vaccine was developed for treating chimpanzees and proved quite effective.

The vaccine works by modifying a chimpanzee cold virus (chimp adenovirus type 3 (ChAd3)1 to carry a limited segment of Ebola Virus genetic material. This spurs the body to create anti-bodies to fight off infection. Because only a limited amount of Ebola genetic material is used, there is no chance of infection.

In initial tests, twenty volunteers received the vaccine in varying doses; one deemed "normal" and the other "high."  The ten receiving the "high" dose created more antibodies much more rapidly than the ten who received the "normal" dose. Antibody production reached a plateau within four weeks of the vaccine being administered. Interestingly, the vaccine not only spurred the creation of Ebola antibodies, it kick-started a rise in T-Cell production.

There were no serious side effects to the test subjects, however two of the volunteers had brief levels of high fever. That high fever lasted less than a day. Half of the test group received a higher-dose and those people produced more antibodies, said the study published in the New England Journal of Medicine.

With this twenty volunteer trial, the National Institute of Allergy and Infectious Diseases is now looking for volunteers for a much larger trial. This means that many months remain for testing before a vaccine will be available for general use. Also, should there be problems during these trials, it could delay the release of the vaccine or halt its development entirely.

 

1 Ebola Vaccine Questions and Answers NIAID/GSK

 

Ebola Treatment

Beyond the use of plasma from survivors, treatment usually consists of the following:

  • balancing fluids
  • maintaining oxygen levels
  • maintaining blood pressure
  • treatment for secondary infections

Note that two version of vaccine are currently in testing (see above). One, developed at the University of Washington1 for simians (monkeys and apes) clears the virus in these animals, but no human trials have been conducted. A second vaccine which consists only of the outer shell of the virus and antibodies and not the infective agent is also in development at Scripps Research Institute2. This vaccine has not been tested on humans either, but has been shown to clear the virus in mice..

1. University of Washington Ebola Vaccine

2. Scripps Research Institute via The Scientist

Keep Calm
Keep Calm
author supplied

Ebola Age and Evolution Rate

How long has it been around. How fast does it change.
Ebola's Age

One of the first questions that science asks about a new-found viron is, how long has this been around? Why haven't we seen it until now? Where did it come from?

All these questions can be addressed, if not answered, by sequencing the RNA or DNA that make up what is being studied. Since Ebola, and it's sister virus Marburg, belong to the same class of viruses, figuring out its age is fairly easy. To determine the age, one first determines the rate of mutation that results in viable change. Also, in this instance, science assume that Marburg and Ebola were the same virus sometime in the past.

With these assumptions in hand and determining the rate of evolution of the virus, the best "guess" on age is two or three thousand years. This figure was derived by working backward along a evolutionary rate that results in both Ebola and Marburg having the exact same structure. In other words, the assumption being that they both evolved from the same virus.

Since humans have not been affected by this virus until 1976, when it was first discovered, science must assume that the virus has been present in animals all this time. Most likely in bats.

Ebola Evolution

Ebola seems to be evolving at the same basic rate as Hepatitis B virus or one hundred times slower than the influenza virus. Assuming that influenza evolves once or twice a year this means Ebola Zaire changes enough to become a new virus every fifty to one hundred years.

Please note that mutations rarely result in evolutionary change. Any structure made up solely of RNA will experience quite a few mutations. Because a mutation rarely replicates or remains viable, it is only one means of evolutionary change.

Source: Oxford Journal - Origin and Evolution of Ebola and Marburg viruses.

Evolutionary Change vs Mutations

United States Patients with Ebola - Statistics

As of Novmber 14, 2014 there is one active cases of Ebola in the United States
Profession Detection Date Status
Kent Brantly (Aid Worker) August 2nd Recovered
Nancy Writebol (Missionary) August 2nd Recovered
Rick Scara (Doctor) September 5th Recovered
Unnamed Doctor September 9th Recovered
Thomas Eric Duncan (Liberian) September 30th Died
Ashoka Mukpo (Cameraman) October 6th Recovered
Nina Pham (Nurse) October 11th Recovered
Amber Joy Vinson (Nurse) October 15th Recovered
Craig Allen Spencer (Doctor/New York) October 23rd Recovered

Dr. Martin Salia (Doctor)

November 14th Died

Ebola vs Human Immunodeficiency Virus

The following paragraphs compare EVD to HIV, a disease Americans know considerably more about.

Mutation
HIV mutates rapidly. A single patient with HIV may have as many as four versions of the virus when he or she finally succumbs. This indicates that HIV can change and evolve fairly easily within the infected body.

Ebola Virus, from Bumba, Republic of Congo, has remained unchanged after nineteen years. For this reason it is highly unlikely that Ebola will transform into an airborne viron.

Transmission
HIV is transmitted via sexual contact, blood, and breast milk.

Ebola is transmitted through body fluids.

Latency
Latency is the time between contracting a virus and displaying symptoms.

HIV can infect a host and remain dormant for up to ten years with no outward signs of infection detectable.

Ebola has almost no latency with sufferers displaying symptoms no later than twenty-one days after exposure and as soon as two days after. In fact, most Ebola sufferers displayed signs of infection within twelve days of contact with an infected individual. The twenty-one day period is the longest period observed by any health professional and is rare. No one, to date, has gone longer than the twenty-one day period from exposure and come down with symptoms or the disease.

Airborne vs Contact Vectors

Often people make assumptions without careful consideration

A bodily fluid includes sputum, blood, urine, sweat, and feces. There have been rumors that both the CDC and WHO lied when they claimed that the virus is NOT airborne. Not only is this untrue is displays a lack of understanding about transmission and what "airborne" actually means.

For example, the droplets from a sneeze are still bodily fluids. Those droplets do not constitute "airborne" by scientific standards. In this way, the droplets from a sneeze are not much different than the droplets from sweat or urine, both fluids of which can fly through the air if sufficient energy is imparted to them.

An airborne contaminant can stay suspended in the air far longer than a drop of liquid affected by gravity. These aerosols can actually stay suspended in the air for minutes or hours or even longer depending on wind conditions.

Anthrax, Chickenpox, Influenza, Measles, Smallpox, Cryptococcosis, and Tuberculosis are all airborne pathogens; Ebola is not.

Notes

This article is subject to frequent changes as more Ebola information becomes available.

Information obtained through the Centers for Disease Control and The World Health Organization unless otherwise noted.

November 17, 2014

Updated list of Ebola patients in the U.S. with Dr. Martin Salia who was admitted to Nebraska Medical Center on November 15th and died in the early morning hours of November 17th. This death changes the statistical probability of death and that change is reflected at twenty percent lethality.

Updated: 12/05/2014, LiamBean
 
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